Heads up:
There are no amended sections in this chapter.
| Adopting agency | BSC | BSC- CG |
SFM | HCD | DSA | OSHPD | BSCC | DPH | AGR | DWR | CEC | CA | SL | SLC | |||||||||
| 1 | 2 | 1/AC | AC | SS | SS/CC | 1 | 1R | 2 | 3 | 4 | 5 | ||||||||||||
| Adopt entire chapter | X | ||||||||||||||||||||||
| Adopt entire chapter as amended (amended sections listed below) |
X | X | X | X | X | X | X | X | X | ||||||||||||||
| Adopt only those sections that are listed below |
X | X | |||||||||||||||||||||
| Chapter / Section | |||||||||||||||||||||||
| 2301.1 | X | ||||||||||||||||||||||
| 2301.1.1 | X | X | X | X | X | X | X | ||||||||||||||||
| 2301.1.2 | X | X | X | X | X | X | X | ||||||||||||||||
| 2301.1.3 | X | X | X | X | |||||||||||||||||||
| 2301.1.3.1 | X | X | X | ||||||||||||||||||||
| 2301.1.3.2 | X | ||||||||||||||||||||||
| 2301.1.4 | X | X | X | X | X | X | X | ||||||||||||||||
| 2301.2, Item 4, Exception | X | X | X | ||||||||||||||||||||
| 2303.1.3.1 | X | X | X | X | X | X | X | ||||||||||||||||
| 2303.1.4.1 | X | X | X | X | X | X | X | ||||||||||||||||
| 2303.2 — 2303.2.9 | X | ||||||||||||||||||||||
| 2303.4.1.4.1, Exception 3 | X | X | X | X | X | X | X | ||||||||||||||||
| 2303.4.3.1 | X | X | X | X | X | X | X | ||||||||||||||||
| 2304.3.1.1 | X | ||||||||||||||||||||||
| 2304.3.4 | X | X | X | X | X | X | X | ||||||||||||||||
| 2304.4.1 | X | X | X | X | X | X | |||||||||||||||||
| 2304.10.1.1 | X | X | X | X | X | X | |||||||||||||||||
| 2304.12.1.1.1 | X | ||||||||||||||||||||||
| 2304.12.1.2, Exception | X | X | X | X | X | X | |||||||||||||||||
| 2304.12.1.4.1 | X | X | X | X | X | X | |||||||||||||||||
| 2304.12.8 | X | ||||||||||||||||||||||
| 2304.12.9 | X | ||||||||||||||||||||||
| 2305.1.2 | X | X | X | X | X | X | X | ||||||||||||||||
| 2308.1 | X | X | |||||||||||||||||||||
| 2308.2.7 | X | X | X | X | X | ||||||||||||||||||
| 2309.1.1 | X | X | X | X | X | ||||||||||||||||||
The Office of the State Fire Marshal's adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
User notes:
About this chapter: Chapter 23 provides minimum requirements for the design of buildings and structures that use wood and wood-based
products. The chapter is organized around three design methodologies: allowable stress design (ASD), load and resistance factor design
(LRFD) and conventional light-frame construction. In addition it allows the use of the American Wood Council Wood Frame Construction Manual
for a limited range of structures. Included in the chapter are references to design and manufacturing standards for various wood and
wood-based products; general construction requirements; design criteria for lateral force-resisting systems and specific requirements for the
application of the three design methods.
Code development reminder: Code change proposals to this chapter will be considered by the IBC—Structural Code Development Committee during the 2019 (Group B) Code Development Cycle. See explanation on page ix.
Code development reminder: Code change proposals to this chapter will be considered by the IBC—Structural Code Development Committee during the 2019 (Group B) Code Development Cycle. See explanation on page ix.
The provisions of this division shall govern the materials, design, construction and quality of wood members and their fasteners.
Hillside buildings (buildings constructed upon slopes steeper than one unit vertical in three units horizontal [33.3% slope]) shall comply with LAMC Subsection 91.1613.9 (seismic design provisions for hillside buildings) and this division.
Hillside buildings (buildings constructed upon slopes steeper than one unit vertical in three units horizontal [33.3% slope]) shall comply with LAMC Subsection 91.1613.9 (seismic design provisions for hillside buildings) and this division.
For the purposes of this chapter, where dimensions of lumber are specified, they shall be deemed to be nominal dimensions unless specifically designated as actual dimensions (see Section 2304.2).
The design of structural elements or systems, constructed partially or wholly of wood or wood-based products, shall be in accordance with one of the following methods:
- Allowable stress design in accordance with Sections 2304, 2305 and 2306.
- Load and resistance factor design in accordance with Sections 2304, 2305 and 2307.
- Conventional light-frame construction in accordance with Sections 2304 and 2308.
- AWC WFCM in accordance with Section 2309.
- The design and construction of log structures in accordance with the provisions of ICC 400.
Structural sawn lumber; end-jointed lumber; prefabricated wood I-joists; structural glued-laminated timber; wood structural panels; fiberboard sheathing (where used structurally); hardboard siding (where used structurally); particleboard; preservative-treated wood; structural log members; structural composite lumber; round timber poles and piles; fire-retardant-treated wood; hardwood plywood; wood trusses; joist hangers; nails; and staples shall conform to the applicable provisions of this section.
Sawn lumber used for load-supporting purposes, including end-jointed or edge-glued lumber, machine stress-rated or machine-evaluated lumber, shall be identified by the grade mark of a lumber grading or inspection agency that has been approved by an accreditation body that complies with DOC PS 20 or equivalent. Grading practices and identification shall comply with rules published by an agency approved in accordance with the procedures of DOC PS 20 or equivalent procedures.
In lieu of a grade mark on the material, a certificate of inspection as to species and grade issued by a lumber grading or inspection agency meeting the requirements of this section is permitted to be accepted for precut, remanufactured or rough-sawn lumber and for sizes larger than 3 inches (76 mm) nominal thickness.
Approved end-jointed lumber is permitted to be used interchangeably with solid-sawn members of the same species and grade. End-jointed lumber used in an assembly required to have a fire-resistance rating shall have the designation "Heat Resistant Adhesive" or "HRA" included in its grade mark.
Structural capacities and design provisions for prefabricated wood I-joists shall be established and monitored in accordance with ASTM D5055.
Glued-laminated timbers shall be manufactured and identified as required in ANSI/AITC A 190.1 and ASTM D3737.
[DSA-SS, DSA-SS/CC and OSHPD 1, 1R, 2, 4 & 5] The construction
documents shall indicate the following:
The design of fasteners and connections shall comply with AITC 117, Section I, Item 6 (Connection Design), and NDS Appendix E.
- Dry or wet service conditions.
- Laminating combinations and stress requirements.
- Species group.
- Preservative material and retention, when preservative treatment is required.
- Provisions for protection during shipping and field handling, such as sealing and wrapping in accordance with AITC 111.
The design of fasteners and connections shall comply with AITC 117, Section I, Item 6 (Connection Design), and NDS Appendix E.
Cross-laminated timbers shall be manufactured and identified in accordance with ANSI/APA PRG 320.
[DSA-SS & DSA-SS/CC & OSHPD 1, 1R, 2, 4 & 5] Requirements in
Section 2303.1.3.1 shall apply to glued cross-laminated
timber.
Wood structural panels, where used structurally (including those used for siding, roof and wall sheathing, subflooring, diaphragms and built-up members), shall conform to the requirements for their type in DOC PS 1, DOC PS 2 or ANSI/APA PRP 210. Each panel or member shall be identified for grade, bond classification, and Performance Category by the trademarks of an approved testing and grading agency. The Performance Category value shall be used as the "nominal panel thickness" or "panel thickness" whenever referenced in this code. Wood structural panel components shall be designed and fabricated in accordance with the applicable standards listed in Section 2306.1 and identified by the trademarks of an approved testing and inspection agency indicating conformance to the applicable standard. In addition, wood structural panels where permanently exposed in outdoor applications shall be of exterior type, except that wood structural panel roof sheathing exposed to the outdoors on the underside is permitted to be Exposure 1 type.
Fiberboard for its various uses shall conform to ASTM C208. Fiberboard sheathing, where used structurally, shall be identified by an approved agency as conforming to ASTM C208.
To ensure tight-fitting assemblies, edges shall be manufactured with square, shiplapped, beveled, tongue-and-groove or U-shaped joints.
Where used as roof insulation in all types of construction, fiberboard shall be protected with an approved roof covering.
Where installed and fireblocked to comply with Chapter 7, fiberboards are permitted as wall insulation in all types of construction. In fire walls and fire barriers, unless treated to comply with Section 803.1 for Class A materials, the boards shall be cemented directly to the concrete, masonry or other noncombustible base and shall be protected with an approved noncombustible veneer anchored to the base without intervening airspaces.
Fiberboard wall insulation applied on the exterior of foundation walls shall be protected below ground level with a bituminous coating.
Hardboard siding shall conform to the requirements of ANSI A135.6 and, where used structurally, shall be identified by the label of an approved agency. Hardboard underlayment shall meet the strength requirements of 7/32-inch (5.6 mm) or 1/4-inch (6.4 mm) service class hardboard planed or sanded on one side to a uniform thickness of not less than 0.200 inch (5.1 mm). Prefinished hardboard paneling shall meet the requirements of ANSI A135.5. Other basic hardboard products shall meet the requirements of ANSI A135.4. Hardboard products shall be installed in accordance with manufacture's recommendations.
Particleboard shall conform to ANSI A208.1. Particleboard shall be identified by the grade mark or certificate of inspection issued by an approved agency. Particleboard shall not be utilized for applications other than indicated in this section unless the particleboard complies with the provisions of Section 2306.3.
Particleboard floor underlayment shall conform to Type PBU of ANSI A208.1. Type PBU underlayment shall be not less than 1/4-inch (6.4 mm) thick and shall be installed in accordance with the instructions of the Composite Panel Association.
Lumber, timber, plywood, piles and poles supporting permanent structures required by Section 2304.12 to be preservative treated shall conform to AWPA U1 and M4. Lumber and plywood used in permanent wood foundation systems shall conform to Chapter 18.
Wood required by Section 2304.12 to be preservative treated shall bear the quality mark of an inspection agency that maintains continuing supervision, testing and inspection over the quality of the preservative-treated wood. Inspection agencies for preservative-treated wood shall be listed by an accreditation body that complies with the requirements of the American Lumber Standards Treated Wood Program, or equivalent. The quality mark shall be on a stamp or label affixed to the preservative-treated wood, and shall include the following information:
- Identification of treating manufacturer.
- Type of preservative used.
- Minimum preservative retention (pcf).
- End use for which the product is treated.
- AWPA standard to which the product was treated.
- Identity of the accredited inspection agency.
Where preservative-treated wood is used in enclosed locations where drying in service cannot readily occur, such wood shall be at a moisture content of 19 percent or less before being covered with insulation, interior wall finish, floor covering or other materials.
Structural capacities for structural composite lumber shall be established and monitored in accordance with ASTM D5456.
Stress grading of structural log members of nonrectangular shape, as typically used in log buildings, shall be in accordance with ASTM D3957. Such structural log members shall be identified by the grade mark of an approved lumber grading or inspection agency. In lieu of a grade mark on the material, a certificate of inspection as to species and grade issued by a lumber grading or inspection agency meeting the requirements of this section shall be permitted.
Round timber poles and piles shall comply with ASTM D3200 and ASTM D25, respectively.
Engineered wood rim boards shall conform to ANSI/APA PRR 410 or shall be evaluated in accordance with ASTM D7672. Structural capacities shall be in accordance with ANSI/APA PRR 410 or established in accordance with ASTM D7672. Rim boards conforming to ANSI/APA PRR 410 shall be marked in accordance with that standard.
Fire-retardant-treated wood is any wood product that, when impregnated with chemicals by a pressure process or other means during manufacture, shall have, when tested in accordance with ASTM E84 or UL 723, a listed flame spread index of 25 or less and show no evidence of significant progressive combustion when the test is continued for an additional 20-minute period. Additionally, the flame front shall not progress more than 101/2 feet (3200 mm) beyond the centerline of the burners at any time during the test.
For wood products impregnated with chemicals by a pressure process, the process shall be performed in closed vessels under pressures not less than 50 pounds per square inch gauge (psig) (345 kPa).
For wood products impregnated with chemicals by other means during manufacture, the treatment shall be an integral part of the manufacturing process of the wood product. The treatment shall provide permanent protection to all surfaces of the wood product. The use of paints, coating, stains or other surface treatments is not an approved method of protection as required in this section.
For wood products produced by other means during manufacture, other than a pressure process, all sides of the wood product shall be tested in accordance with and produce the results required in Section 2303.2. Wood structural panels shall be permitted to test only the front and back faces.
In addition to the labels required in Section 2303.1.1 for sawn lumber and Section 2303.1.5 for wood structural panels, each piece of fire-retardant-treated lumber and wood structural panels shall be labeled. The label shall contain the following items:
- The identification mark of an approved agency in accordance with Section 1703.5.
- Identification of the treating manufacturer.
- The name of the fire-retardant treatment.
- The species of wood treated.
- Flame spread and smoke-developed index.
- Method of drying after treatment.
- Conformance with appropriate standards in accordance with Sections 2303.2.5 through 2303.2.8.
- For fire-retardant-treated wood exposed to weather, damp or wet locations, include the words "No increase in the listed classification when subjected to the Standard Rain Test" (ASTM D2898).
Design values for untreated lumber and wood structural panels, as specified in Section 2303.1, shall be adjusted for fire-retardant-treated wood. Adjustments to design values shall be based on an approved method of investigation that takes into consideration the effects of the anticipated temperature and humidity to which the fire-retardant-treated wood will be subjected, the type of treatment and redrying procedures.
The effect of treatment and the method of redrying after treatment, and exposure to high temperatures and high humidities on the flexure properties of fire-retardant-treated softwood plywood shall be determined in accordance with ASTM D5516. The test data developed by ASTM D5516 shall be used to develop adjustment factors, maximum loads and spans, or both, for untreated plywood design values in accordance with ASTM D6305. Each manufacturer shall publish the allowable maximum loads and spans for service as floor and roof sheathing for its treatment.
For each species of wood that is treated, the effects of the treatment, the method of redrying after treatment and exposure to high temperatures and high humidities on the allowable design properties of fire-retardant-treated lumber shall be determined in accordance with ASTM D5664. The test data developed by ASTM D5664 shall be used to develop modification factors for use at or near room temperature and at elevated temperatures and humidity in accordance with ASTM D6841. Each manufacturer shall publish the modification factors for service at temperatures of not less than 80°F (27°C) and for roof framing. The roof framing modification factors shall take into consideration the climatological location.
Where fire-retardant-treated wood is exposed to weather, or damp or wet locations, it shall be identified as "Exterior" to indicate there is no increase in the listed flame spread index as defined in Section 2303.2 when subjected to ASTM D2898.
Interior fire-retardant-treated wood shall have moisture content of not over 28 percent when tested in accordance with ASTM D3201 procedures at 92-percent relative humidity. Interior fire-retardant-treated wood shall be tested in accordance with Section 2303.2.5.1 or 2303.2.5.2. Interior fire-retardant-treated wood designated as Type A shall be tested in accordance with the provisions of this section.
Fire-retardant-treated wood shall be dried to a moisture content of 19 percent or less for lumber and 15 percent or less for wood structural panels before use. For wood kiln-dried after treatment (KDAT), the kiln temperatures shall not exceed those used in kiln drying the lumber and plywood submitted for the tests described in Section 2303.2.5.1 for plywood and 2303.2.5.2 for lumber.
See Section 603.1 for limitations on the use of fire-retardant-treated wood in buildings of Type I or II construction.
Hardwood and decorative plywood shall be manufactured and identified as required in HPVA HP-1.
Wood trusses shall be designed in accordance with the provisions of this code and accepted engineering practice. Members are permitted to be joined by nails, glue, bolts, timber connectors, metal connector plates or other approved framing devices.
The written, graphic and pictorial depiction of each individual truss shall be provided to the building official for approval prior to installation. Truss design drawings shall be provided with the shipment of trusses delivered to the job site. Truss design drawings shall include, at a minimum, the following information:
- Slope or depth, span and spacing.
- Location of all joints and support locations.
- Number of plies if greater than one.
- Required bearing widths.
Design loads as applicable, including:
- Other lateral loads, including drag strut loads.
- Adjustments to wood member and metal connector plate design value for conditions of use.
- Maximum reaction force and direction, including maximum uplift reaction forces where applicable.
- Joint connection type and description, such as size and thickness or gage, and the dimensioned location of each joint connector except where symmetrically located relative to the joint interface.
- Size, species and grade for each wood member.
- Truss-to-truss connections and truss field assembly requirements.
- Calculated span-to-deflection ratio and maximum vertical and horizontal deflection for live and total load as applicable.
- Maximum axial tension and compression forces in the truss members.
- Required permanent individual truss member restraint location and the method and details of restraint/bracing to be used in accordance with Section 2303.4.1.2.
Where permanent restraint of truss members is required on the truss design drawings, it shall be accomplished by one of the following methods:
- Permanent individual truss member restraint/bracing shall be installed using standard industry lateral restraint/bracing details in accordance with generally accepted engineering practice. Locations for lateral restraint shall be identified on the truss design drawing.
- The trusses shall be designed so that the buckling of any individual truss member is resisted internally by the individual truss through suitable means (for example, buckling reinforcement by T-reinforcement or L-reinforcement, proprietary reinforcement). The buckling reinforcement of individual members of the trusses shall be installed as shown on the truss design drawing or on supplemental truss member buckling reinforcement details provided by the truss designer.
- A project-specific permanent individual truss member restraint/bracing design shall be permitted to be specified by any registered design professional.
The owner or the owner's authorized agent shall contract with any qualified registered design professional for the design of the temporary installation restraint/bracing and the permanent individual truss member restraint/bracing for all trusses with clear spans 60 feet (18 288 mm) or greater.
The individual or organization responsible for the design of trusses.
Where required by the registered design professional, the building official or the statutes of the jurisdiction in which the project is to be constructed, each individual truss design drawing shall bear the seal and signature of the truss designer.
Exceptions:
- Where a cover sheet and truss index sheet are combined into a single sheet and attached to the set of truss design drawings, the single cover/truss index sheet is the only document required to be signed and sealed by the truss designer.
- Where a cover sheet and a truss index sheet are separately provided and attached to the set of truss design drawings, the cover sheet and the truss index sheet are the only documents required to be signed and sealed by the truss designer.
- [DSA-SS, DSA-SS/CC and OSHPD 1, 1R, 2, 4 & 5] Exceptions 1 and 2 are not permitted by DSA and OSHPD.
The truss manufacturer shall provide a truss placement diagram that identifies the proposed location for each individually designated truss and references the corresponding truss design drawing. The truss placement diagram shall be provided as part of the truss submittal package, and with the shipment of trusses delivered to the job site. Truss placement diagrams that serve only as a guide for installation and do not deviate from the permit submittal drawings shall not be required to bear the seal or signature of the truss designer.
The truss submittal package provided by the truss manufacturer shall consist of each individual truss design drawing, the truss placement diagram, the permanent individual truss member restraint/bracing method and details and any other structural details germane to the trusses; and, as applicable, the cover/truss index sheet.
[DSA-SS, DSA-SS/CC and OSHPD 1, 1R, 2, 4 & 5] In addition to Sections
2303.4.1 and 2303.4.2, the following requirements
apply:
- Construction documents. The construction documents
prepared by the registered engineer or
licensed architect for the project shall indicate
all requirements for the truss design, including:
- Deflection criteria.
- Connection details to structural and nonstructural elements (e.g. non-bearing partitions).
- Requirements for approval. The truss design drawings and engineering analysis shall be provided to the enforcement agency and approved prior to truss fabrication, in accordance with the California Administrative Code (Title 24, Part 1). Alterations to the approved truss design drawings or manufactured trusses are subject to the approval of the enforcement agency.
The design for the transfer of loads and anchorage of each truss to the supporting structure is the responsibility of the registered design professional.
Truss members and components shall not be cut, notched, drilled, spliced or otherwise altered in any way without written concurrence and approval of a registered design professional. Alterations resulting in the addition of loads to any member (for example, HVAC equipment, piping, additional roofing or insulation) shall not be permitted without verification that the truss is capable of supporting such additional loading.
In addition to Sections 2303.4.1 through 2303.4.5, the design, manufacture and quality assurance of metal-plate-connected wood trusses shall be in accordance with TPI 1. Job-site inspections shall be in compliance with Section 110.4, as applicable.
Trusses not part of a manufacturing process in accordance with either Section 2303.4.6 or a referenced standard, which provides requirements for quality control done under the supervision of a third-party quality control agency, shall be manufactured in compliance with Sections 1704.2.5 and 1705.5, as applicable.
Joist hangers shall be in accordance with ASTM D7147.
Nails and staples shall conform to requirements of ASTM F1667, including Supplement 1. Nails used for framing and sheathing connections shall have minimum average bending yield strengths as follows: 80 kips per square inch (ksi) (551 MPa) for shank diameters larger than 0.177 inch (4.50 mm) but not larger than 0.254 inch (6.45 mm), 90 ksi (620 MPa) for shank diameters larger than 0.142 inch (3.61 mm) but not larger than 0.177 inch (4.50 mm) and 100 ksi (689 MPa) for shank diameters of not less than 0.099 inch (2.51 mm) but not larger than 0.142 inch (3.61 mm). Staples used for framing and sheathing connections shall have minimum average bending moments as follows: 3.6 in.-lbs (0.41 N-m) for No. 16 gage staples, 4.0 in.-lbs (0.45 N-m) for No. 15 gage staples, and 4.3 in.-lbs (0.49 N-m) for No. 14 gage staples.
Consideration shall be given in design to the possible effect of cross-grain dimensional changes considered vertically that may occur in lumber fabricated in a green condition.
The provisions of this section apply to design methods specified in Section 2302.1.
Computations to determine the required sizes of members shall be based on the net dimensions (actual sizes) and not nominal sizes.
The framing of exterior and interior walls shall be in accordance with the provisions specified in Section 2308 unless a specific design is furnished.
Studs shall have full bearing on a 2-inch-thick (actual 11/2-inch, 38 mm) or larger plate or sill having a width not less than equal to the width of the studs.
Annular spaces
around pipes, electric cables, conduits or other openings
in bottom/sole plates at exterior walls shall be protected
against the passage of rodents by closing such
openings in accordance with the California Green
Building Standards Code (CALGreen), Chapter 4,
Division 4.4.
Wood walls and bearing partitions shall not support more than two floors and a roof unless an analysis satisfactory to the building official shows that shrinkage of the wood framing will not have adverse effects on the structure or any plumbing, electrical or mechanical systems or other equipment installed therein due to excessive shrinkage or differential movements caused by shrinkage. The analysis shall show that the roof drainage system and the foregoing systems or equipment will not be adversely affected or, as an alternate, such systems shall be designed to accommodate the differential shrinkage or movements.
[DSA-SS, DSA-SS/CC
and OSHPD 1, 1R, 2, 4 & 5] The following additional
requirements apply:
- Engineering analysis shall be furnished that demonstrates compliance of wall framing elements and connections with Section 2302.1, Item 1 or 2.
-
Construction documents shall include detailing of sill
plate anchorage to supporting masonry or concrete
for all exterior and interior bearing, nonbearing and
shear walls. Unless specifically designed in accordance
with Item 1 above, sills under exterior walls,
bearing walls and shear walls shall be bolted to
masonry or concrete with 5/8 inch diameter by 12-inch
(16 mm by 305 mm) bolts spaced not more than four
(4) feet (1219 mm) on center, with a minimum of two
(2) bolts for each piece of sill plate. Anchor bolts
shall have a 4 inch minimum and a 12-inch maximum
clearance to the end of the sill plate, and 7-inch minimum
embedment into concrete or masonry.
Unless specifically designed in accordance with Item 1 above, sill plates under nonbearing interior partitions on concrete floor slabs shall be anchored at not more than four (4) feet (1219 mm) on center to resist a minimum allowable stress shear of 100 pounds per linear foot (1.4 kN/m) acting either parallel or perpendicular to the wall. - Construction documents shall include detailing and limitations for notches and bored holes in wall studs, plates and sills.
The framing of wood-joisted floors and wood-framed roofs shall be in accordance with the provisions specified in Section 2308 unless a specific design is furnished.
[DSA-SS, DSA-SS/CC
and OSHPD 1, 1R, 2, 4 & 5] The following additional
requirements apply:
- Engineering analysis shall be furnished that demonstrates compliance of floor, roof and ceiling framing elements and connections with Section 2302.1, Items 1 or 2.
- Construction documents shall include detailing and limitations for notches and bored holes in floor and roof framing members.
Combustible framing shall be not less than 2 inches (51 mm), but shall be not less than the distance specified in Sections 2111 and 2113 and the California Mechanical Code, from flues, chimneys and fireplaces, and 6 inches (152 mm) away from flue openings.
Wall sheathing on the outside of exterior walls, including gables, and the connection of the sheathing to framing shall be designed in accordance with the general provisions of this code and shall be capable of resisting wind pressures in accordance with Section 1609.
Where wood structural panel sheathing is used as the exposed finish on the outside of exterior walls, it shall have an exterior exposure durability classification. Where wood structural panel sheathing is used elsewhere, but not as the exposed finish, it shall be of a type manufactured with exterior glue (Exposure 1 or Exterior). Wood structural panel sheathing, connections and framing spacing shall be in accordance with Table 2304.6.1 for the applicable wind speed and exposure category where used in enclosed buildings with a mean roof height not greater than 30 feet (9144 mm) and a topographic factor (Kz t) of 1.0.
MAXIMUM ALLOWABLE STRESS DESIGN WIND SPEED, Vasd PERMITTED FOR WOOD STRUCTURAL PANEL WALL SHEATHING USED TO RESIST WIND PRESSURESa, b, c
| MINIMUM NAIL | MINIMUM WOOD STRUCTURAL PANEL SPAN RATING | MINIMUM NOMINAL PANEL THICKNESS (inches) | MAXIMUM WALL STUD SPACING (inches) | PANEL NAIL SPACING | MAXIMUM ALLOWABLE STRESS DESIGN WIND SPEED, Vasd d (MPH) | ||||
| Size | Penetration (inches) | Edges (inches o.c.) | Field (inches o.c.) | Wind exposure category | |||||
| B | C | D | |||||||
| 6d common (2.0" × 0.113") | 1.5 | 24/0 | 3/8 | 16 | 6 | 12 | 110 | 90 | 85 |
| 24/16 | 7/16 | 16 | 6 | 12 | 110 | 100 | 90 | ||
| 6 | 150 | 125 | 110 | ||||||
| 8d common (2.5" × 0.131") | 1.75 | 24/16 | 7/16 | 16 | 6 | 12 | 130 | 110 | 105 |
| 6 | 150 | 125 | 110 | ||||||
| 24 | 6 | 12 | 110 | 90 | 85 | ||||
| 6 | 110 | 90 | 85 | ||||||
For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s.
- Panel strength axis shall be parallel or perpendicular to supports. Three-ply plywood sheathing with studs spaced more than 16 inches on center shall be applied with panel strength axis perpendicular to supports.
- The table is based on wind pressures acting toward and away from building surfaces in accordance with Section 30.7 of ASCE 7. Lateral requirements shall be in accordance with Section 2305 or 2308.
- Wood structural panels with span ratings of wall-16 or wall-24 shall be permitted as an alternative to panels with a 24/0 span rating. Plywood siding rated 16 on center or 24 on center shall be permitted as an alternative to panels with a 24/16 span rating. Wall-16 and plywood siding 16 on center shall be used with studs spaced not more than 16 inches on center.
- Vasd shall be determined in accordance with Section 1609.3.1.
Softwood wood structural panels used for interior paneling shall conform to the provisions of Chapter 8 and shall be installed in accordance with Table 2304.10.1. Panels shall comply with DOC PS 1, DOC PS 2 or ANSI/APA PRP 210. Prefinished hardboard paneling shall meet the requirements of ANSI A135.5. Hardwood plywood shall conform to HPVA HP-1.
Structural floor sheathing and structural roof sheathing shall comply with Sections 2304.8.1 and 2304.8.2, respectively.
ALLOWABLE SPANS FOR LUMBER FLOOR AND ROOF SHEATHING
| SPAN (inches) | MINIMUM NET THICKNESS (inches) OF LUMBER PLACED | |||
| Perpendicular to supports | Diagonally to supports | |||
| Surfaced drya | Surfaced unseasoned | Surfaced drya | Surfaced unseasoned | |
| Floors | ||||
| 24 | 3/4 | 25/32 | 3/4 | 25/32 |
| 16 | 5/8 | 11/16 | 5/8 | 11/16 |
| Roofs | ||||
| 24 | 5/8 | 11/16 | 3/4 | 25/32 |
For SI: 1 inch = 25.4 mm.
- Maximum 19-percent moisture content.
| SOLID FLOOR OR ROOF SHEATHING | SPACED ROOF SHEATHING | GRADING RULES |
| Utility | Standard | NLGA, WCLIB, WWPA |
| 4 common or utility | 3 common or standard | NLGA, WCLIB, WWPA, NSLB or NELMA |
| No. 3 | No. 2 | SPIB |
| Merchantable | Construction common | RIS |
ALLOWABLE SPANS AND LOADS FOR WOOD STRUCTURAL PANEL SHEATHING AND SINGLE-FLOOR GRADES CONTINUOUS OVER TWO OR MORE SPANS WITH STRENGTH AXIS PERPENDICULAR TO SUPPORTSa
| SHEATHING GRADES | ROOFb | FLOORc | ||||
| Panel span rating roof/ floor span | Panel thickness (inches) | Maximum span (inches) | Loadd(psf) | Maximum span (inches) | ||
| With edge supporte | Without edge support | Total load | Live load | |||
| 16/0 | 3/8 | 16 | 16 | 40 | 30 | 0 |
| 20/0 | 3/8 | 20 | 20 | 40 | 30 | 0 |
| 24/0 | 3/8, 7/16, 1/2 | 24 | 20f | 40 | 30 | 0 |
| 24/16 | 7/16, 1/2 | 24 | 24 | 50 | 40 | 16 |
| 32/16 | 15/32, 1/2, 5/8 | 32 | 28 | 40 | 30 | 16g |
| 40/20 | 19/32, 5/8, 3/4, 7/8 | 40 | 32 | 40 | 30 | 20g,h |
| 48/24 | 23/32, 3/4, 7/8 | 48 | 36 | 45 | 35 | 24 |
| 54/32 | 7/8, 1 | 54 | 40 | 45 | 35 | 32 |
| 60/32 | 7/8, 11/8 | 60 | 48 | 45 | 35 | 32 |
| SINGLE FLOOR GRADES | ROOFb | FLOORc | ||||
| Panel span rating | Panel thickness (inches) | Maximum span (inches) | Loade (psf) | Maximum span (inches) | ||
| With edge supporte | Without edge support | Total load | Live load | |||
| 16 o.c. | 1/2, 19/32, 5/8 | 24 | 24 | 50 | 40 | 16g |
| 20 o.c. | 19/32, 5/8, 3/4 | 32 | 32 | 40 | 30 | 20g,h |
| 24 o.c. | 23/32, 3/4 | 48 | 36 | 35 | 25 | 24 |
| 32 o.c. | 7/8, 1 | 48 | 40 | 50 | 40 | 32 |
| 48 o.c. | 13/32, 11/8 | 60 | 48 | 50 | 40 | 48 |
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kN/m2.
- Applies to panels 24 inches or wider.
- Uniform load deflection limitations 1/180 of span under live load plus dead load, 1/240 under live load only.
- Panel edges shall have approved tongue-and-groove joints or shall be supported with blocking unless 1/4-inch minimum thickness underlayment or 11/2 inches of approved cellular or lightweight concrete is placed over the subfloor, or finish floor is 3/4-inch wood strip. Allowable uniform load based on deflection of 1/360 of span is 100 pounds per square foot except the span rating of 48 inches on center is based on a total load of 65 pounds per square foot.
- Allowable load at maximum span.
- Tongue-and-groove edges, panel edge clips (one midway between each support, except two equally spaced between supports 48 inches on center), lumber blocking or other. Only lumber blocking shall satisfy blocked diaphragm requirements.
- For 1/2-inch panel, maximum span shall be 24 inches.
- Span is permitted to be 24 inches on center where 3/4-inch wood strip flooring is installed at right angles to joist.
- Span is permitted to be 24 inches on center for floors where 11/2 inches of cellular or lightweight concrete is applied over the panels.
ALLOWABLE SPAN FOR WOOD STRUCTURAL PANEL COMBINATION SUBFLOOR-UNDERLAYMENT (SINGLE FLOOR)a (Panels Continuous Over Two or More Spans and Strength Axis Perpendicular to Supports)
| IDENTIFICATION | MAXIMUM SPACING OF JOISTS (inches) | ||||
| 16 | 20 | 24 | 32 | 48 | |
| Species groupb | Thickness (inches) | ||||
| 1 | 1/2 | 5/8 | 3/4 | — | — |
| 2, 3 | 5/8 | 3/4 | 7/8 | — | — |
| 4 | 3/4 | 7/8 | 1 | — | — |
| Single floor span ratingc | 16 o.c. | 20 o.c. | 24 o.c. | 32 o.c. | 48 o.c. |
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kN/m2.
- Spans limited to value shown because of possible effects of concentrated loads. Allowable uniform loads based on deflection of 1/360 of span is 100 pounds per square foot except allowable total uniform load for 11/8-inch wood structural panels over joists spaced 48 inches on center is 65 pounds per square foot. Panel edges shall have approved tongue-and-groove joints or shall be supported with blocking, unless 1/4-inch minimum thickness underlayment or 11/2 inches of approved cellular or lightweight concrete is placed over the subfloor, or finish floor is 3/4-inch wood strip.
- Applicable to all grades of sanded exterior-type plywood. See DOC PS 1 for plywood species groups.
- Applicable to Underlayment grade, C-C (Plugged) plywood, and Single Floor grade wood structural panels.
ALLOWABLE LOAD (PSF) FOR WOOD STRUCTURAL PANEL ROOF SHEATHING CONTINUOUS OVER TWO OR MORE SPANS AND STRENGTH AXIS PARALLEL TO SUPPORTS (Plywood structural panels are five-ply, five-layer unless otherwise noted)a
| PANEL GRADE | THICKNESS (inch) | MAXIMUM SPAN (inches) | LOAD AT MAXIMUM SPAN (psf) | |
| Live | Total | |||
| Structural I sheathing | 7/16 | 24 | 20 | 30 |
| 15/32 | 24 | 35b | 45b | |
| 1/2 | 24 | 40b | 50b | |
| 19/32, 5/8 | 24 | 70 | 80 | |
| 23/32, 3/4 | 24 | 90 | 100 | |
| Sheathing, other grades covered in DOC PS 1 or DOC PS 2 | 7/16 | 16 | 40 | 50 |
| 15/32 | 24 | 20 | 25 | |
| 1/2 | 24 | 25 | 30 | |
| 19/32 | 24 | 40b | 50b | |
| 5/8 | 24 | 45b | 55b | |
| 23/32, 3/4 | 24 | 60b | 65b | |
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kN/m2.
Structural floor sheathing shall be designed in accordance with the general provisions of this code.
Floor sheathing conforming to the provisions of Table 2304.8(1), 2304.8(2), 2304.8(3) or 2304.8(4) shall be deemed to meet the requirements of this section.
Structural roof sheathing shall be designed in accordance with the general provisions of this code and the special provisions in this section.
Roof sheathing conforming to the provisions of Table 2304.8(1), 2304.8(2), 2304.8(3) or 2304.8(5) shall be deemed to meet the requirements of this section. Wood structural panel roof sheathing shall be of a type manufactured with exterior glue (Exposure 1 or Exterior).
Lumber decking shall be designed and installed in accordance with the general provisions of this code and Sections 2304.9.1 through 2304.9.5.3.
Section 2304.9.1 of the 2019 CBC is adopted by reference.
Connections for wood members shall be designed in accordance with the appropriate methodology in CBC Section 2301.2. The number and size of fasteners connection wood members shall not be less than that set forth in LAMC Table 2304.10.1. Staple fasteners in LAMC Table 2304.10.1 shall not be used to resist or transfer seismic forces in structure assigned to Seismic Design Category D, E or F.
EXCEPTION:
Staples may be used to resist or transfer seismic forces when the allowable shear values are substantiated by cyclic testing and approved by the Superintendent of Building.
Lumber decking is permitted to be laid up following one of five standard patterns as defined in Sections 2304.9.2.1 through 2304.9.2.5. Other patterns are permitted to be used provided that they are substantiated through engineering analysis.
All pieces shall be supported on their ends (in other words, by two supports).
All pieces shall be supported by three supports, and all end joints shall occur in line on alternating supports. Supporting members shall be designed to accommodate the load redistribution caused by this pattern.
Courses in end spans shall be alternating simple-span pattern and two-span continuous pattern. End joints shall be staggered in adjacent courses and shall bear on supports.
The decking shall extend across not fewer than three spans. Pieces in each starter course and every third course shall be simple span pattern. Pieces in other courses shall be cantilevered over the supports with end joints at alternating quarter or third points of the spans. Each piece shall bear on one support or more.
The decking shall extend across not fewer than three spans. End joints of pieces within 6 inches (152 mm) of the end joints of the adjacent pieces in either direction shall be separated by not fewer than two intervening courses. In the end bays, each piece shall bear on one support or more. Where an end joint occurs in an end bay, the next piece in the same course shall continue over the first inner support for not less than 24 inches (610 mm). The details of the controlled random pattern shall be as specified for each decking material in Section 2304.9.3.3, 2304.9.4.3 or 2304.9.5.3.
Decking that cantilevers beyond a support for a horizontal distance greater than 18 inches (457 mm), 24 inches (610 mm) or 36 inches (914 mm) for 2-inch (51 mm), 3-inch (76 mm) and 4-inch (102 mm) nominal thickness decking, respectively, shall comply with the following:
- The maximum cantilevered length shall be 30 percent of the length of the first adjacent interior span.
- A structural fascia shall be fastened to each decking piece to maintain a continuous, straight line.
- End joints shall not be in the decking between the cantilevered end of the decking and the centerline of the first adjacent interior span.
Mechanically laminated decking shall comply with Sections 2304.9.3.1 through 2304.9.3.3.
Mechanically laminated decking consists of square-edged dimension lumber laminations set on edge and nailed to the adjacent pieces and to the supports.
The length of nails connecting laminations shall be not less than two and one-half times the net thickness of each lamination. Where decking supports are 48 inches (1219 mm) on center or less, side nails shall be installed not more than 30 inches (762 mm) on center alternating between top and bottom edges, and staggered one-third of the spacing in adjacent laminations. Where supports are spaced more than 48 inches (1219 mm) on center, side nails shall be installed not more than 18 inches (457 mm) on center alternating between top and bottom edges and staggered one-third of the spacing in adjacent laminations. For mechanically laminated decking constructed with laminations of 2-inch (51 mm) nominal thickness, nailing in accordance with Table 2304.9.3.2 shall be permitted. Two side nails shall be installed at each end of butt-jointed pieces. Laminations shall be toenailed to supports with 20d or larger common nails. Where the supports are 48 inches (1219 mm) on center or less, alternate laminations shall be toenailed to alternate supports; where supports are spaced more than 48 inches (1219 mm) on center, alternate laminations shall be toenailed to every support. For mechanically laminated decking constructed with laminations of 2-inch (51 mm) nominal thickness, toenailing in accordance with Table 2304.9.3.2 shall be permitted.
| MINIMUM NAIL SIZE (Length x Diameter) (inches) | MAXIMUM SPACING BETWEEN FACE NAILS a, b (inches) | NUMBER OF TOENAILS INTO SUPPORTSc | |
| Decking Supports ≤ 48 inches o.c. | Decking Supports > 48 inches o.c. | ||
| 4 × 0.192 | 30 | 18 | 1 |
| 4 × 0.162 | 24 | 14 | 2 |
| 4 × 0.148 | 22 | 13 | 2 |
| 31/2 × 0.162 | 20 | 12 | 2 |
| 31/2 × 0.148 | 19 | 11 | 2 |
| 31/2 × 0.135 | 17 | 10 | 2 |
| 3 × 0.148 | 11 | 7 | 2 |
| 3 × 0.128 | 9 | 5 | 2 |
| 23/4 × 0.148 | 10 | 6 | 2 |
| 23/4 × 0.131 | 9 | 6 | 3 |
| 23/4 × 0.120 | 8 | 5 | 3 |
For SI: 1 inch = 25.4 mm
- Nails shall be driven perpendicular to the lamination face, alternating between top and bottom edges.
- Where nails penetrate through two laminations and into the third, they shall be staggered one-third of the spacing in adjacent laminations. Otherwise, nails shall be staggered one-half of the spacing in adjacent laminations.
- Where supports are 48 inches on center or less, alternate laminations shall be toenailed to alternate supports; where supports are spaced more than 48 inches on center, alternate laminations shall be toenailed to every support.
There shall be a minimum distance of 24 inches (610 mm) between end joints in adjacent courses. The pieces in the first and second courses shall bear on not fewer than two supports with end joints in these two courses occurring on alternate supports. Not more than seven intervening courses shall be permitted before this pattern is repeated.
Two-inch (51 mm) sawn tongue-and-groove decking shall comply with Sections 2304.9.4.1 through 2304.9.4.3.
Two-inch (51 mm) decking shall have a maximum moisture content of 15 percent. Decking shall be machined with a single tongue-and-groove pattern. Each decking piece shall be nailed to each support.
Each piece of decking shall be toenailed at each support with one 16d common nail through the tongue and face-nailed with one 16d common nail.
There shall be a minimum distance of 24 inches (610 mm) between end joints in adjacent courses. The pieces in the first and second courses shall bear on not fewer than two supports with end joints in these two courses occurring on alternate supports. Not more than seven intervening courses shall be permitted before this pattern is repeated.
Three- and four-inch (76 mm and 102 mm) sawn tongue-and-groove decking shall comply with Sections 2304.9.5.1 through 2304.9.5.3.
Three-inch (76 mm) and four-inch (102 mm) decking shall have a maximum moisture content of 19 percent. Decking shall be machined with a double tongue-and-groove pattern. Decking pieces shall be interconnected and nailed to the supports.
Each piece shall be toenailed at each support with one 40d common nail and face-nailed with one 60d common nail. Courses shall be spiked to each other with 8-inch (203 mm) spikes at maximum intervals of 30 inches (762 mm) through predrilled edge holes penetrating to a depth of approximately 4 inches (102 mm). One spike shall be installed at a distance not exceeding 10 inches (254 mm) from the end of each piece.
There shall be a minimum distance of 48 inches (1219 mm) between end joints in adjacent courses. Pieces not bearing on a support are permitted to be located in interior bays provided that the adjacent pieces in the same course continue over the support for not less than 24 inches (610 mm). This condition shall not occur more than once in every six courses in each interior bay.
Connections for wood members shall be designed in accordance with the appropriate methodology in Section 2302.1. The number and size of fasteners connecting wood members shall be not less than that set forth in Table 2304.10.1.
| DESCRIPTION OF BUILDING ELEMENTS | NUMBER AND TYPE OF FASTENER | SPACING AND LOCATION | |
| Roof | |||
| 1. Blocking between ceiling joists, rafters or trusses to top plate or other framing below | 3-8d common (21/2" × 0.131"); or 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3"14 gage staples, 7/16" crown |
Each end, toenail | |
| Blocking between rafters or truss not at the wall top plate, to rafter or truss | 2-8d common (21/2" × 0.131") 2-3" × 0.131" nails 2-3" 14 gage staples |
Each end, toenail | |
| 2-16 d common (31/2" × 0.162") 3-3" × 0.131" nails 3-3" 14 gage staples |
End nail | ||
| Flat blocking to truss and web filler | 16d common (31/2" × 0.162") @ 6" o.c. 3" × 0.131" nails @ 6" o.c. 3" × 14 gage staples @ 6" o.c |
Face nail | |
| 2. Ceiling joists to top plate | 3-8d common (21/2" × 0.131"); or 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
Each joist, toenail | |
| 3. Ceiling joist not attached to parallel rafter, laps over partitions (no thrust) (see Section 2308.7.3.1, Table 2308.7.3.1) |
3-16d common (31/2" × 0.162"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown |
Face nail | |
| 4. Ceiling joist attached to parallel rafter (heel joint) (see Section 2308.7.3.1, Table 2308.7.3.1) |
Per Table 2308.7.3.1 | Face nail | |
| 5. Collar tie to rafter | 3-10d common (3" × 0.148"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown |
Face nail | |
| 6. Rafter or roof truss to top plate (See Section 2308.7.5, Table 2308.7.5) |
3-10 common (3" × 0.148"); or 3-16d box (31/2" × 0.135"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131 nails; or 4-3" 14 gage staples, 7/16" crown |
Toenailc | |
| 7. Roof rafters to ridge valley or hip rafters; or roof rafter to 2-inch ridge beam | 2-16d common (31/2" × 0.162"); or 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown; or |
End nail | |
| 3-10d common (3" × 0.148"); or 4-16d box (31/2" × 0.135"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown |
Toenail | ||
| Wall | |||
| 8. Stud to stud (not at braced wall panels) | 16d common (31/2" × 0.162"); | 24" o.c. face nail | |
| 10d box (3" × 0.128"); or 3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
16" o.c. face nail | ||
| 9. Stud to stud and abutting studs at intersecting wall corners (at braced wall panels) | 16d common (31/2" × 0.162"); or | 16" o.c. face nail | |
| 16d box (31/2" × 0.135"); or | 12" o.c. face nail | ||
| 3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
12" o.c. face nail | ||
| 10. Built-up header (2" to 2" header) | 16d common (31/2" × 0.162"); or | 16" o.c. each edge, face nail | |
| 16d box (31/2" × 0.135") | 12" o.c. each edge, face nail | ||
| 11. Continuous header to stud | 4-8d common (21/2" × 0.131"); or 4-10d box (3" × 0.128") |
Toenail | |
| 12. Top plate to top plate | 16d common (31/2" × 0.162"); or | 16" o.c. face nail | |
| 10d box (3" × 0.128"); or 3" × 0.131" nails; or 3" 14 gage staples, 7/16" crown |
12" o.c. face nail | ||
| 13. Top plate to top plate, at end joints | 8-16d common (31/2" × 0.162"); or 12-10d box (3" × 0.128"); or 12-3" × 0.131" nails; or 12-3" 14 gage staples, 7/16" crown |
Each side of end joint, face nail (minimum 24" lap splice length each side of end joint) | |
| 14. Bottom plate to joist, rim joist, band joist or blocking (not at braced wall panels) | 16d common (31/2" × 0.162"); or | 16" o.c. face nail | |
| 16d box (31/2" × 0.135"); or 3" × 0.131" nails; or 3" 14 gage staples, 7/16" crown |
12" o.c. face nail | ||
| 15. Bottom plate to joist, rim joist, band joist or blocking at braced wall panels | 2-16d common (31/2" × 0.162"); or 3-16d box (31/2" × 0.135"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown |
16" o.c. face nail | |
| 16. Stud to top or bottom plate | 4-8d common (21/2" × 0.131"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown; or |
Toenail | |
| 2-16d common (31/2" × 0.162"); or 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
End nail | ||
| 17. Top plates, laps at corners and intersections | 2-16d common (31/2" × 0.162"); or 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
Face nail | |
| 18. 1" brace to each stud and plate | 2-8d common (21/2" × 0.131"); or 2-10d box (3" × 0.128"); or 2-3" × 0.131" nails; or 2-3" 14 gage staples, 7/16" crown |
Face nail | |
| 19. 1" × 6" sheathing to each bearing | 2-8d common (21/2" × 0.131"); or 2-10d box (3" × 0.128") |
Face nail | |
| 20. 1" × 8" and wider sheathing to each bearing | 3-8d common (21/2" × 0.131"); or 3-10d box (3" × 0.128") |
Face nail | |
| Floor | |||
| 21. Joist to sill, top plate, or girder | 3-8d common (21/2" × 0.131"); or floor 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
Toenail | |
| 22. Rim joist, band joist, or blocking to top plate, sill or other framing below | 8d common (21/2" × 0.131"); or 10d box (3" × 0.128"); or 3" × 0.131" nails; or 3" 14 gage staples, 7/16" crown |
6" o.c., toenail | |
| 23. 1" × 6" subfloor or less to each joist | 2-8d common (21/2" × 0.131"); or 2-10d box (3" × 0.128") |
Face nail | |
| 24. 2" subfloor to joist or girder | 2-16d common (31/2" × 0.162") | Face nail | |
| 25. 2" planks (plank & beam — floor & roof) | 2-16d common (31/2" × 0.162") | Each bearing, face nail | |
| 26. Built-up girders and beams, 2" lumber layers | 20d common (4" × 0.192") | 32" o.c., face nail at top and bottom staggered on opposite sides | |
| 10d box (3" × 0.128"); or 3" × 0.131" nails; or 3" 14 gage staples, 7/16" crown |
24" o.c. face nail at top and bottom staggered on opposite sides | ||
| And: 2-20d common (4" × 0.192"); or 3-10d box (3" × 0.128"); or 3-3" × 0.131" nails; or 3-3" 14 gage staples, 7/16" crown |
Ends and at each splice, face nail | ||
| 27. Ledger strip supporting joists or rafters | 3-16d common (31/2" × 0.162"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown |
Each joist or rafter, face nail | |
| 28. Joist to band joist or rim joist | 3-16d common (31/2" × 0.162"); or 4-10d box (3" × 0.128"); or 4-3" × 0.131" nails; or 4-3" 14 gage staples, 7/16" crown |
End nail | |
| 29. Bridging or blocking to joist, rafter or truss | 2-8d common (21/2" × 0.131"); or 2-10d box (3" × 0.128"); or 2-3" × 0.131" nails; or 2-3" 14 gage staples, 7/16" crown |
Each end, toenail | |
| Wood structural panels (WSP), subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framinga | |||
| Edges (inches) |
Intermediate supports (inches) |
||
| 30. 3/8" — 1/2" | 6d common or deformed (2" × 0.113") (subfloor and wall) | 6 | 12 |
| 8d common or deformed (21/2" × 0.131") (roof) or RSRS-01 (23/8" × 0.113") nail (roof)d | 6 | 12 | |
| 23/8" × 0.113" nail (subfloor and wall) | 6 | 12 | |
| 13/4" 16 gage staple, 7/16" crown (subfloor and wall) |
4 | 8 | |
| 23/8" × 0.113" nail (roof) | 4 | 8 | |
| 13/4" 16 gage staple, 7/16" crown (roof) | 3 | 6 | |
| 31. 19/32" — 3/4" | 8d common (21/2" × 0.131"); or 6d deformed (2" × 0.113") (subfloor and wall) |
6 | 12 |
| 8d common or deformed (21/2" × 0.131") (roof) or RSRS-01 (23/8" × 0.113") nail (roof)d |
6 | 12 | |
| 23/8" × 0.113" nail; or 2" 16 gage staple, 7/16" crown |
4 | 8 | |
| 32. 7/8" — 11/4" | 10d common (3" × 0.148"); or 8d deformed (21/2" × 0.131") |
6 | 12 |
| Other exterior wall sheathing | |||
| 33. 1/2" fiberboard sheathingb | 11/2" galvanized roofing nail (7/16" head diameter); or 11/4" 16 gage staple with 7/16" or 1" crown |
3 | 6 |
| 34. 25/32" fiberboard sheathingb | 13/4" galvanized roofing nail (7/16" diameter head); or 11/2" 16 gage staple with 7/16" or 1" crown |
3 | 6 |
| Wood structural panels, combination subfloor underlayment to framing | |||
| 35. 3/4" and less | 8d common (21/2" × 0.131"); or 6d deformed (2" × 0.113") |
6 | 12 |
| 36. 7/8" — 1" | 8d common (21/2" × 0.131"); or 8d deformed (21/2" × 0.131") |
6 | 12 |
| 37. 11/8" — 11/4" | 10d common (3" × 0.148"); or 8d deformed (21/2" × 0.131") |
6 | 12 |
| Panel siding to framing | |||
| 38. 1/2" or less | 6d corrosion-resistant siding (17/8" × 0.106"); or 6d corrosion-resistant casing (2" × 0.099") |
6 | 12 |
| 39. 5/8" | 8d corrosion-resistant siding (23/8" × 0.128"); or 8d corrosion-resistant casing (21/2" × 0.113") |
6 | 12 |
| Interior paneling | |||
| 40. 1/4" | 4d casing (11/2" × 0.080"); or 4d finish (11/2" × 0.072") |
6 | 12 |
| 41. 3/8" | 6d casing (2" × 0.099"); or 6d finish (Panel supports at 24 inches) |
6 | 12 |
For SI: 1 inch = 25.4 mm.
- Nails spaced at 6 inches at intermediate supports where spans are 48 inches or more. For nailing of wood structural panel and particleboard diaphragms and shear walls, refer to Section 2305. Nails for wall sheathing are permitted to be common, box or casing.
- Spacing shall be 6 inches on center on the edges and 12 inches on center at intermediate supports for nonstructural applications. Panel supports at 16 inches (20 inches if strength axis in the long direction of the panel, unless otherwise marked).
- Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule and the ceiling joist is fastened to the top plate in accordance with this schedule, the number of toenails in the rafter shall be permitted to be reduced by one nail.
- Staples shall not be used to resist or transfer seismic forces in structures assigned to Seismic Design Category D, E or F.
[DSA-SS and
OSHPD 1, 1R, 2, 4 & 5] Fasteners used for the attachment
of exterior wall coverings shall be of hot-dipped
zinc-coated galvanized steel, mechanically deposited
zinc-coated steel, stainless steel, silicon bronze or copper.
The coating weights for hot-dipped zinc-coated
fasteners shall be in accordance with ASTM A153. The
coating weights for mechanically deposited zinc coated
fasteners shall be in accordance with ASTM B695,
Class 55 minimum.
Sheathing nails or other approved sheathing connectors shall be driven so that their head or crown is flush with the surface of the sheathing.
Connections depending on joist hangers or framing anchors, ties and other mechanical fastenings not otherwise covered are permitted where approved. The vertical load-bearing capacity, torsional moment capacity and deflection characteristics of joist hangers shall be determined in accordance with ASTM D7147.
Fasteners, including nuts and washers, and connectors in contact with preservative-treated and fire-retardant-treated wood shall be in accordance with Sections 2304.10.5.1 through 2304.10.5.4. The coating weights for zinc-coated fasteners shall be in accordance with ASTM A153. Stainless steel driven fasteners shall be in accordance with the material requirements of ASTM F1667.
Fasteners, including nuts and washers, in contact with preservative-treated wood shall be of hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Staples shall be of stainless steel. Fasteners other than nails, staples, timber rivets, wood screws and lag screws shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B695, Class 55 minimum. Connectors that are used in exterior applications and in contact with preservative-treated wood shall have coating types and weights in accordance with the treated wood or connector manufacturer's recommendations. In the absence of manufacturer's recommendations, not less than ASTM A653, Type G185 zinc-coated galvanized steel, or equivalent, shall be used.
Exception: Plain carbon steel fasteners, including nuts and washers, in SBX/DOT and zinc borate preservative-treated wood in an interior, dry environment shall be permitted.
Fastenings, including nuts and washers, for wood foundations shall be as required in AWC PWF.
Fasteners, including nuts and washers, for fire-retardant-treated wood used in exterior applications or wet or damp locations shall be of hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Staples shall be of stainless steel. Fasteners other than nails, staples, timber rivets, wood screws and lag screws shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B695, Class 55 minimum.
Fasteners, including nuts and washers, for fire-retardant-treated wood used in interior locations shall be in accordance with the manufacturer's recommendations. In the absence of manufacturer's recommendations, Section 2304.10.5.3 shall apply.
Where wall framing members are not continuous from the foundation sill to the roof, the members shall be secured to ensure a continuous load path. Where required, sheet metal clamps, ties or clips shall be formed of galvanized steel or other approved corrosion-resistant material not less than 0.0329-inch (0.836 mm) base metal thickness.
Wood columns and posts shall be framed to provide full end bearing. Alternatively, column-and-post end connections shall be designed to resist the full compressive loads, neglecting end-bearing capacity. Column-and-post end connections shall be fastened to resist lateral and net induced uplift forces.
Where a structure, portion thereof or individual structural elements are required by provisions of this code to be of heavy timber, the building elements therein shall comply with the applicable provisions of Sections 2304.11.1 through 2304.11.4. Minimum dimensions of heavy timber shall comply with the applicable requirements in Table 2304.11 based on roofs or floors supported and the configuration of each structural element, or in Sections 2304.11.2 through 2304.11.4. Lumber decking shall be in accordance with Section 2304.9.
MINIMUM DIMENSIONS OF HEAVY TIMBER STRUCTURAL MEMBERS
| MINIMUM NOMINAL
SOLID SAWN SIZE
|
MINIMUM GLUED-
LAMINATED NET SIZE
|
MINIMUM STRUCTURAL
COMPOSITE LUMBER NET SIZE
|
|||||
| SUPPORTING | HEAVY TIMBER STRUCTURAL
ELEMENTS
|
Width, inch | Depth, inch | Width, inch | Depth, inch | Width, inch | Depth, inch |
| Floor loads only
or combined floor
and roof loads |
Columns;
Framed sawn or glued-laminated
timber arches that spring from the
floor line;
Framed timber trusses |
8 | 8 | 63/4 | 81/4 | 7 | 71/2 |
| Wood beams and girders | 6 | 10 | 5 | 101/2 | 51/4 | 91/2 | |
| Roof loads only | Columns (roof and ceiling loads);
Lower half of: wood-frame
or glued-laminated arches
that spring from the floor
line or from grade |
6 | 8 | 5 | 81/4 | 51/4 | 71/2 |
| Upper half of: wood-frame
or glued-laminated arches
that spring from the floor
line or from grade
|
6 | 6 | 5 | 6 | 51/4 | 51/2 | |
| Framed timber trusses and other
roof framing; a
Framed or glued-laminated
arches that spring from the top
of walls or wall abutments |
4b | 6 | 3b | 67/8 | 31/2b | 51/2 | |
For SI: 1 inch = 25.4 mm.
- Spaced members shall be permitted to be composed of two or more pieces not less than 3 inches nominal in thickness where blocked solidly throughout their intervening spaces or where spaces are tightly closed by a continuous wood cover plate of not less than 2 inches nominal in thickness secured to the underside of the members. Splice plates shall be not less than 3 inches nominal in thickness.
- Where protected by approved automatic sprinklers under the roof deck, framing members shall be not less than 3 inches nominal in width.
Heavy timber structural members shall be detailed and constructed in accordance with Sections 2304.11.1 through 2304.11.1.3.
Minimum dimensions of columns shall be in accordance with Table 2304.11. Columns shall be continuous or superimposed throughout all stories and connected in an approved manner. Girders and beams at column connections shall be closely fitted around columns and adjoining ends shall be cross tied to each other, or intertied by caps or ties, to transfer horizontal loads across joints. Wood bolsters shall not be placed on tops of columns unless the columns support roof loads only. Where traditional heavy timber detailing is used, connections shall be by means of reinforced concrete or metal caps with brackets, by properly designed steel or iron caps, with pintles and base plates, by timber splice plates affixed to the columns by metal connectors housed within the contact faces, or by other approved methods.
Minimum dimensions of floor framing shall be in accordance with Table 2304.11. Approved wall plate boxes or hangers shall be provided where wood beams, girders or trusses rest on masonry or concrete walls. Where intermediate beams are used to support a floor, they shall rest on top of girders, or shall be supported by an approved metal hanger into which the ends of the beams shall be closely fitted. Where traditional heavy timber detailing is used, these connections shall be permitted to be supported by ledgers or blocks securely fastened to the sides of the girders.
Minimum dimensions of roof framing shall be in accordance with Table 2304.11. Every roof girder and not less than every alternate roof beam shall be anchored to its supporting member to resist forces as required in Chapter 16.
Exterior walls shall permitted to be cross-laminated timber meeting the requirements of Section 2303.1.4.
Interior walls and partitions shall be of solid wood construction formed by not less than two layers of 1-inch (25 mm) matched boards or laminated construction 4 inches (102 mm) thick, or of 1-hour fire-resistance-rated construction.
Floors shall be without concealed spaces. Wood floors shall be constructed in accordance with Section 2304.11.3.1 or 2304.11.3.2.
Cross-laminated timber shall be not less than 4 inches (102 mm) in actual thickness. Cross-laminated timber shall be continuous from support to support and mechanically fastened to one another. Cross-laminated timber shall be permitted to be connected to walls without a shrinkage gap providing swelling or shrinking is considered in the design. Corbelling of masonry walls under the floor shall be permitted to be used.
Sawn or glued-laminated plank floors shall be one of the following:
- Sawn or glued-laminated planks, splined or tongue-and-groove, of not less than 3 inches (76 mm) nominal in thickness covered with 1-inch (25 mm) nominal dimension tongue-and-groove flooring, laid crosswise or diagonally, 15/32-inch (12 mm) wood structural panel or 1/2-inch (12.7 mm) particleboard.
- Planks not less than 4 inches (102 mm) nominal in width set on edge close together and well spiked and covered with 1-inch (25 mm) nominal dimension flooring or 15/32-inch (12 mm) wood structural panel or 1/2-inch (12.7 mm) particleboard.
The lumber shall be laid so that continuous lines of joints will occur only at points of support. Floors shall not extend closer than 1/2 inch (12.7 mm) to walls. Such 1/2-inch (12.7 mm) space shall be covered by a molding fastened to the wall and so arranged that it will not obstruct the swelling or shrinkage movements of the floor. Corbelling of masonry walls under the floor shall be permitted to be used in place of molding.
Roofs shall be without concealed spaces and roof decks shall be constructed in accordance with Section 2304.11.4.1 or 2304.11.4.2. Other types of decking shall be an alternative that provides equivalent fire resistance and structural properties. Where supported by a wall, roof decks shall be anchored to walls to resist forces determined in accordance with Chapter 16. Such anchors shall consist of steel bolts, lags, screws or approved hardware of sufficient strength to resist prescribed forces.
Cross-laminated timber roofs shall be not less than 3 inches (76 mm) nominal in thickness and shall be continuous from support to support and mechanically fastened to one another.
Sawn, wood structural panel, or glued-laminated plank roofs shall be one of the following:
- Sawn or glued laminated, splined or tongue-and-groove plank, not less than 2 inches (51 mm) nominal in thickness.
- 11/8-inch-thick (32 mm) wood structural panel (exterior glue).
- Planks not less than 3 inches (76 mm) nominal in width, set on edge close together and laid as required for floors.
Wood used above ground in the locations specified in Sections 2304.12.1.1 through 2304.12.1.5, 2304.12.3 and 2304.12.5 shall be naturally durable wood or preservative-treated wood using waterborne preservatives, in accordance with AWPA U1 for above-ground use.
Wood joists or wood structural floors that are closer than 18 inches (457 mm) or wood girders that are closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated areas located within the perimeter of the building foundation shall be of naturally durable or preservative-treated wood.
[SPCB] There shall be a clearance of
at least 18 inches (457 mm) between the underside
of wood floor joists and the finished surface of the
ground, and at least 12 inches (305 mm) between the
underside of any other wood horizontal framing
member and the finished surface of the ground. The
ground underneath floor joists shall be leveled or
smoothed off so as to maintain a reasonably even
surface.
Exception: For purposes of structural pest control
inspection, a minimum of 12 inches (305 mm) of clearance under-floor joists shall be considered
adequate except that such clearance shall
not be necessary where the subarea soil is of such
a nature as to prevent excavation or where excavation
would create a hazard from shifting soil or
other causes.
Wood framing members, including wood sheathing, that are in contact with exterior foundation walls and are less than 8 inches (203 mm) from exposed earth shall be of naturally durable or preservative-treated wood.
Exception: [DSA-SS and OSHPD 1, 1R, 2, 4 & 5]
At exterior walls where the earth is paved with an
asphalt or concrete slab at least 18 inches (457 mm)
wide and draining away from the building, the bottom
of sills are permitted to be 6 inches (152 mm)
above the top of such slab. Other equivalent means
of termite and decay protection may be accepted by
the enforcement agency.
Wood framing members and furring strips in direct contact with the interior of exterior masonry or concrete walls below grade shall be of naturally durable or preservative-treated wood.
Sleepers and sills on a concrete or masonry slab that is in direct contact with earth shall be of naturally durable or preservative-treated wood.
[DSA-SS
and OSHPD 1, 1R, 2, 4 & 5] Stud walls or partitions
at shower or toilet rooms with more than two
plumbing fixtures, excluding floor drains, and stud
walls adjacent to unroofed paved areas shall rest on
a concrete curb extending at least 6 inches (152
mm) above finished floor and pavement level.
Clearance between wood siding and earth on the exterior of a building shall be not less than 6 inches (152 mm) or less than 2 inches (51 mm) vertical from concrete steps, porch slabs, patio slabs and similar horizontal surfaces exposed to the weather except where siding, sheathing and wall framing are of naturally durable or preservative-treated wood.
Wood used in the locations specified in Sections 2304.12.2.1 through 2304.12.2.5 shall be naturally durable wood or preservative-treated wood in accordance with AWPA U1. Preservative-treated wood used in interior locations shall be protected with two coats of urethane, shellac, latex epoxy or varnish unless waterborne preservatives are used. Prior to application of the protective finish, the wood shall be dried in accordance with the manufacturer's recommendations.
The ends of wood girders entering exterior masonry or concrete walls shall be provided with a 1/2-inch (12.7 mm) airspace on top, sides and end, unless naturally durable or preservative-treated wood is used.
Posts or columns supporting permanent structures and supported by a concrete or masonry slab or footing that is in direct contact with the earth shall be of naturally durable or preservative-treated wood.
Exception: Posts or columns that meet all of the following:
- Are not exposed to the weather, or are protected by a roof, eave, overhang, or other covering if exposed to the weather.
- Are supported by concrete piers or metal pedestals projected not less than 1 inch (25 mm) above the slab or deck and are separated from the concrete pier by an impervious moisture barrier.
- Are located not less than 8 inches (203 mm) above exposed earth.
Naturally durable or preservative-treated wood shall be utilized for those portions of wood members that form the structural supports of buildings, balconies, porches or similar permanent building appurtenances where such members are exposed to the weather without adequate protection from a roof, eave, overhang or other covering to prevent moisture or water accumulation on the surface or at joints between members.
Exception: Buildings located in a geographical region where experience has demonstrated that climatic conditions preclude the need to use durable materials where the structure is exposed to the weather.
The portions of glued-laminated timbers that form the structural supports of a building or other structure and are exposed to weather and not fully protected from moisture by a roof, eave or similar covering shall be pressure treated with preservative or be manufactured from naturally durable or preservative-treated wood.
Wood structural members that support moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, shall be of naturally durable or preservative-treated wood unless separated from such floors or roofs by an impervious moisture barrier. The impervious moisture barrier system protecting the structure supporting floors shall provide positive drainage of water that infiltrates the moisture-permeable floor topping.
Enclosed framing in exterior balconies and elevated walking surfaces that are exposed to rain, snow or drainage from irrigation shall be provided with openings that provide a net free cross-ventilation area not less than 1/150 of the area of each separate space.
Wood used in contact with exposed earth shall be naturally durable for both decay and termite resistance or preservative treated in accordance with AWPA U1 for soil or fresh water use.
Exception: Untreated wood is permitted where such wood is continuously and entirely below the ground-water level or submerged in fresh water.
Posts and columns that are supporting permanent structures and embedded in concrete that is exposed to the weather or in direct contact with the earth shall be of preservative-treated wood.
In geographical areas where hazard of termite damage is known to be very heavy, wood floor framing in the locations specified in Section 2304.12.1.1 and exposed framing of exterior decks or balconies shall be of naturally durable species (termite resistant) or preservative treated in accordance with AWPA U1 for the species, product preservative and end use or provided with approved methods of termite protection.
Wood installed in retaining or crib walls shall be preservative treated in accordance with AWPA U1 (Commodity Specifications A or F) for soil and fresh water use. Wood shall not be used in retaining walls or cribs for structures assigned to Seismic Design Category D, E or F.
For under-floor ventilation (crawl space), see Section 1202.4.
[SPCB] Correct the
conditions in frame and stucco walls and similar appurtenant
construction so that the wood framing is separate
from the main structure by a complete concrete or
masonry plug with no voids that will allow infestations to
enter the structure from the wall. If there is no plug, the
foundation shall be 2 inches (51 mm) or more above the
grade levels and at least as high as the adjoining slabs or
4-inch (102 mm) concrete barrier seat off installed.
[SPCB] Separate the earth fills such
as under porches or paving from all woodwork by concrete,
masonry, good quality cement plaster or other material
approved by local building codes. Chemical treatment of
earth fills is considered adequate if the foundation adjoining
the fill meets standards of the current building codes.
Wood members supporting concrete, masonry or similar materials shall be checked for the effects of long-term loading using the provisions of the ANSI/AWC NDS. The total deflection, including the effects of long-term loading, shall be limited in accordance with Section 1604.3.1 for these supported materials.
Exception: Horizontal wood members supporting masonry or concrete nonstructural floor or roof surfacing not more than 4 inches (102 mm) thick need not be checked for long-term loading.
Structures using wood-frame shear walls or wood-frame diaphragms to resist wind, seismic or other lateral loads shall be designed and constructed in accordance with AWC SDPWS and the applicable provisions of Sections 2305, 2306 and 2307.
[DSA-SS, DSA-SS/CC
and OSHPD 1, 1R, 2, 4 & 5] See Section 2301.1.4 for
modifications to AWC SDPWS.
The deflection of wood-frame diaphragms shall be determined in accordance with AWC SDPWS. The deflection (Δdia) of a blocked wood structural panel diaphragm uniformly fastened throughout with staples is permitted to be calculated in accordance with Equation 23-1. If not uniformly fastened, the constant 0.188 (For SI: 1/1627) in the third term shall be modified by an approved method.
For SI: Δdia = 0.052vL3/EAW + vL/4Gt + Len/1627 + Σ(xΔc)/2W
Δdia = 5vL3/8EAW + vL/4Gt + 0.188Len + Σ(xΔc)/2W
(Equation 23-1)
For SI: Δdia = 0.052vL3/EAW + vL/4Gt + Len/1627 + Σ(xΔc)/2W
| where: | ||
| A | = | Area of chord cross section, in square inches (mm2). |
| E | = | Modulus of elasticity of diaphragm chords, in pounds per square inch (N/mm2). |
| en | = | Staple slip, in inches (mm) [see Table 2305.2(1)]. |
| Gt | = | Panel rigidity through the thickness, in pounds per inch (N/mm) of panel width or depth [see Table 2305.2(2)]. |
| L | = | Diaphragm length (dimension perpendicular to the direction of the applied load), in feet (mm). |
| v | = | Induced unit shear in pounds per linear foot (plf) (N/mm). |
| W | = | Diaphragm width [in the direction of applied force, in feet (mm)]. |
| x | = | Distance from chord splice to nearest support, in feet (mm). |
| Δc | = | Diaphragm chord splice slip at the induced unit shear, in inches (mm). |
| Δdia | = | Maximum mid-span diaphragm deflection determined by elastic analysis, in inches (mm). |
| LOAD PER FASTENERb (pounds) | FASTENER DESIGNATIONS |
| 14-Ga staple × 2 inches long | |
| 60 | 0.011 |
| 80 | 0.018 |
| 100 | 0.028 |
| 120 | 0.04 |
| 140 | 0.053 |
| 160 | 0.068 |
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 4.448 N.
| PANEL TYPE | SPAN RATING | VALUES OF Gt (lb/in. panel depth or width) | |||||||
| Structural Sheathing | Structural I | ||||||||
| Plywood | OSB | Plywood | OSB | ||||||
| 3-ply | 4-ply | 5-plya | 3-ply | 4-ply | 5-plya | ||||
| Sheathing | 24/0 | 25,000 | 32,500 | 37,500 | 77,500 | 32,500 | 42,500 | 41,500 | 77,500 |
| 24/16 | 27,000 | 35,000 | 40,500 | 83,500 | 35,000 | 45,500 | 44,500 | 83,500 | |
| 32/16 | 27,000 | 35,000 | 40,500 | 83,500 | 35,000 | 45,500 | 44,500 | 83,500 | |
| 40/20 | 28,500 | 37,000 | 43,000 | 88,500 | 37,000 | 48,000 | 47,500 | 88,500 | |
| 48/24 | 31,000 | 40,500 | 46,500 | 96,000 | 40,500 | 52,500 | 51,000 | 96,000 | |
| Single Floor | 16 o.c. | 27,000 | 35,000 | 40,500 | 83,500 | 35,000 | 45,500 | 44,500 | 83,500 |
| 20 o.c. | 28,000 | 36,500 | 42,000 | 87,000 | 36,500 | 47,500 | 46,000 | 87,000 | |
| 24 o.c. | 30,000 | 39,000 | 45,000 | 93,000 | 39,000 | 50,500 | 49,500 | 93,000 | |
| 32 o.c. | 36,000 | 47,000 | 54,000 | 110,000 | 47,000 | 61,000 | 59,500 | 110,000 | |
| 48 o.c. | 50,500 | 65,500 | 76,000 | 155,000 | 65,500 | 85,000 | 83,500 | 155,000 | |
| Structural Sheathing | Structural I | ||||||
| Thickness (in.) | A-A, A-C | Marine | All Other Grades | A-A, A-C | Marine | All Other Grades | |
| Sanded Plywood | 1/4 | 24,000 | 31,000 | 24,000 | 31,000 | 31,000 | 31,000 |
| 11/32 | 25,500 | 33,000 | 25,500 | 33,000 | 33,000 | 33,000 | |
| 3/8 | 26,000 | 34,000 | 26,000 | 34,000 | 34,000 | 34,000 | |
| 15/32 | 38,000 | 49,500 | 38,000 | 49,500 | 49,500 | 49,500 | |
| 1/2 | 38,500 | 50,000 | 38,500 | 50,000 | 50,000 | 50,000 | |
| 19/32 | 49,000 | 63,500 | 49,000 | 63,500 | 63,500 | 63,500 | |
| 5/8 | 49,500 | 64,500 | 49,500 | 64,500 | 64,500 | 64,500 | |
| 23/32 | 50,500 | 65,500 | 50,500 | 65,500 | 65,500 | 65,500 | |
| 3/4 | 51,000 | 66,500 | 51,000 | 66,500 | 66,500 | 66,500 | |
| 7/8 | 52,500 | 68,500 | 52,500 | 68,500 | 68,500 | 68,500 | |
| 1 | 73,500 | 95,500 | 73,500 | 95,500 | 95,500 | 95,500 | |
| 11/8 | 75,000 | 97,500 | 75,000 | 97,500 | 97,500 | 97,500 | |
The deflection of wood-frame shear walls shall be determined in accordance with AWC SDPWS. The deflection (Δsw) of a blocked wood structural panel shear wall uniformly fastened throughout with staples is permitted to be calculated in accordance with Equation 23-2.
Δsw = 8vh3/EAb + vh/4Gt + 0.75hen + dah/b
(Equation 23-2)
| where: | ||
| A | = | Area of end-post cross section in square inches (mm2). |
| b | = | Shear wall length, in feet (mm). |
| da | = | Total vertical elongation of wall anchorage system (such as fastener slip, device elongation, rod elongation) at the induced unit shear in the shear wall (v). |
| E | = | Modulus of elasticity of end posts, in pounds per square inch (N/mm2). |
| en | = | Staple slip, in inches (mm) [see Table 2305.2(1)]. |
| Gt | = | Panel rigidity through the thickness, in pounds per inch (N/mm) of panel width or depth [see Table 2305.2(2)]. |
| h | = | Shear wall height, in feet (mm). |
| v | = | Induced unit shear, in pounds per linear foot (N/mm). |
| Δsw | = | Maximum shear wall deflection determined by elastic analysis, in inches (mm). |
In Seismic Design Category D, E or F, mechanically driven nails used in wood structural panel shear walls shall meet the same dimensions as that required for hand-driven nails, including diameter, minimum length and minimum head diameter. Clipped head or box nails are not permitted in new construction. The allowable design value for clipped head nails in existing construction may be taken at no more than the nail-head-area ratio of that of the same size hand-driven nails.
In Seismic Design Category D, E or F, hold-down connectors shall be designed to resist shear wall overturning moments using approved cyclic load values or 75 percent of the allowable seismic load values that do not consider cyclic loading of the product. Connector bolts into wood framing shall require steel plate washers on the post on the opposite side of the anchorage device. Plate size shall be a minimum of 0.229 inch by 3 inches by 3 inches (5.82 mm by 76 mm by 76 mm) in size. Holddown connectors shall be finger tight and 1/2 turn just prior to covering the wall framing.
The design and construction of wood elements in structures using allowable stress design shall be in accordance with the following applicable standards:
American Wood Council.
| ANSI/AWC NDS | National Design Specification for Wood Construction |
| SDPWS | Special Design Provisions for Wind and Seismic |
American Society of Agricultural and Biological Engineers.
| ASABE EP 484.3 | Diaphragm Design of Metal-clad, Wood-Frame Rectangular Buildings |
| ASABE EP 486.2 | Shallow Post Foundation Design |
| ASABE EP 559.1 | Design Requirements and Bending Properties for Mechanically Laminated Wood Assemblies |
APA—The Engineered Wood Association.
| ANSI 117 Standard Specifications for Structural Glued Laminated Timber of Softwood Species | |
| ANSI A190.1 Structural Glued Laminated Timber | |
| Panel Design Specification | |
| Plywood Design Specification Supplement 1— | |
| Plywood Design Specification Supplement 2—
Design & Fabrication of Glued Plywood-lumber Beams
|
|
| Plywood Design Specification Supplement 3— | |
| Plywood Design Specification Supplement 4— | |
| Plywood Design Specification Supplement 5—
Design & Fabrication of All-plywood Beams
|
|
| APA T300 | Glulam Connection Details |
| APA S560 | Field Notching and Drilling of Glued
Laminated Timber Beams
|
| APA S475 | Glued Laminated Beam Design Tables |
| APA X450 | Glulam in Residential Construction |
| APA X440 | Product and Application Guide: Glulam |
| APA R540 | Builders Tips: Proper Storage and Handling of Glulam Beams |
Truss Plate Institute, Inc.
| TPI 1 | National Design Standard for Metal Plate Connected Wood Truss Construction |
West Coast Lumber Inspection Bureau
| AITC 104 | Typical Construction Details | |
| AITC 110 | Standard Appearance Grades for Structural Glued Laminated Timber | |
| AITC 113 | Standard for Dimensions of Structural Glued Laminated Timber | |
| AITC 119 | Standard Specifications for Structural Glued Laminated Timber of Hardwood Species | |
| AITC 200 | Inspection Manual |
The design of rafter spans is permitted to be in accordance with the AWC STJR.
The design of plank and beam flooring is permitted to be in accordance with the AWC Wood Construction Data No. 4.
The allowable unit stresses for preservative-treated wood need not be adjusted for treatment, but are subject to other adjustments.
The allowable unit stresses for fire-retardant-treated wood, including fastener values, shall be developed from an approved method of investigation that considers the effects of anticipated temperature and humidity to which the fire-retardant-treated wood will be subjected, the type of treatment and the redrying process. Other adjustments are applicable except that the impact load duration shall not apply.
The capacity of lumber decking arranged according to the patterns described in Section 2304.9.2 shall be the lesser of the capacities determined for flexure and deflection according to the formulas in Table 2306.1.4.
ALLOWABLE LOADS FOR LUMBER DECKING
| PATTERN | ALLOWABLE AREA LOADa, b | |
| Flexure | Deflection | |
| Simple span | ||
| Two-span continuous | ||
| Combination simple- and two-span continuous | ||
| Cantilevered pieces intermixed | ||
| Controlled random layup | ||
| Mechanically laminated decking | ||
| 2-inch decking | ||
| 3-inch and 4-inch decking | ||
- σb = Allowable total uniform load limited by bending.
σΔ = Allowable total uniform load limited by deflection. - d = Actual decking thickness.
l = Span of decking.
Fb' = Allowable bending stress adjusted by applicable factors.
E' = Modulus of elasticity adjusted by applicable factors.
Wood-frame diaphragms shall be designed and constructed in accordance with AWC SDPWS. Where panels are fastened to framing members with staples, requirements and limitations of AWC DPWS shall be met and the allowable shear values set forth in CBC Table 2306.2(1) or 2306.2(2) shall only be permitted for structures assigned to Seismic Design Category A, B or C.
The allowable shear values of CBC Tables 2306.2(1) and 2306.2(2) are permitted to be increased 40% for wind design.
Wood structural panel diaphragms used to resist seismic forces in structures assigned to Seismic Design Category D, E or F shall be applied directly to the framing members.
EXCEPTION: Allowable shear values where panels are fastened to framing members with staples may be used if such values are substantiated by cyclic testing and approved by the building official.
The allowable shear values of CBC Tables 2306.2(1) and 2306.2(2) are permitted to be increased 40% for wind design.
Wood structural panel diaphragms used to resist seismic forces in structures assigned to Seismic Design Category D, E or F shall be applied directly to the framing members.
Wood-frame shear walls shall be designed and constructed in accordance with AWC SDPWS. For structures assigned to Seismic Design Category D, E, or F, application of Tables 4.3A and 4.3B of AWC SDPWS shall include the following:
Where panels are fastened to framing members with staples, requirements and limitations of AWC SDPWS shall be met and the allowable shear values set forth in CBC Tables 2306.3(1), 2306.3(2) or 2306.3(3) shall only be permitted for structures assigned to Seismic Design Category A, B or C.
The allowable shear values in CBC Tables 2306.3(1) and 2306.3(2) are permitted to be increased 40% for wind design. Panels complying with ANSI/APA PRP-210 shall be permitted to use design values for Plywood Siding in the AWC SDPWS.
- Wood structural panel thickness for shear walls shall not be less than 3/8 inch (9.525 mm) thick, and studs shall not be spaced at more than 16 inches (406.4 mm) on center.
- The maximum nominal unit shear capacities for three-ply plywood resisting seismic forces in structures assigned to Seismic Design Category D, E or F is 400 pounds per linear foot (plf) (181.43 kg per meter).
- Where shear design values using allowable stress design (ASD) exceed 350 plf or load and resistance factor design (LRFD) exceed 500 plf, all framing members receiving edge nailing from abutting panels shall not be less than a single 3 inch (76.19 mm) nominal member, or two 2 inch (50.8 mm) nominal members fastened together in accordance with CBC Section 2306.1 to transfer the design shear value between framing members. Wood structural panel joint and sill plate nailing shall be staggered at all panel edges. See Sections 4.3.6.1 and 4.3.6.4.3 of AWC SDPWS for sill plate size and anchorage requirements.
- Nails shall be placed not less than 1/2 inch (12.7 mm) in from the panel edges and not less than 3/8 inch (9.525 mm) from the edge of the connecting members for shear greater than 350 plf using ASD or 500 plf using LRFD. Nails shall be placed not less than 3/8 inch (9.525 mm) from panel edges and not less than 1/4 inch (6.35 mm) from the edge of the connecting members for shears of 350 plf or less using ASD or 500 plf or less using LRFD.
- Table 4.3B of AWC SDPWS application is not allowed for structures assigned to Seismic design category D, E or F.
Where panels are fastened to framing members with staples, requirements and limitations of AWC SDPWS shall be met and the allowable shear values set forth in CBC Tables 2306.3(1), 2306.3(2) or 2306.3(3) shall only be permitted for structures assigned to Seismic Design Category A, B or C.
EXCEPTION:
Where panels are fastened to framing members with staples, allowable shear values may be used if such values are substantiated by cyclic testing and approved by the Superintendent of Building.
The allowable shear values in CBC Tables 2306.3(1) and 2306.3(2) are permitted to be increased 40% for wind design. Panels complying with ANSI/APA PRP-210 shall be permitted to use design values for Plywood Siding in the AWC SDPWS.
Sheer walls sheathed with Portland cement plaster, gypsum lath, gypsum sheathing or gypsum board shall be designed and constructed in accordance with AWC SDPWS. Shear walls sheathed with these materials are permitted to resist horizontal forces using the allowable shear capacities set forth in CBC Table 2306.3(3). Shear walls sheathed with Portland cement plaster, gypsum lath, gypsum sheathing or gypsum board shall not be used to resist seismic forces in structures assigned to Seismic Design Category E or F.
Shear walls sheathed with lath, plaster or gypsum board shall not be used below the top level in a multi-level building for structures assigned to Seismic Design Category D.
Shear walls sheathed with lath, plaster or gypsum board shall not be used below the top level in a multi-level building for structures assigned to Seismic Design Category D.
The design and construction of wood elements and structures using load and resistance factor design shall be in accordance with ANSI/AWC NDS and AWC SDPWS.
The requirements of this section are intended for conventional light-frame construction. Other construction methods are permitted to be used, provided that a satisfactory design is submitted showing compliance with other provisions of this code. Interior nonload-bearing partitions, ceilings and curtain walls of conventional light-frame construction are not subject to the limitations of Section 2308.2.
Where portions of a building of otherwise conventional light-frame construction exceed the limits of Section 2308.2, those portions and the supporting load path shall be designed in accordance with accepted engineering practice and the provisions of this code. For the purposes of this section, the term "portions" shall mean parts of buildings containing volume and area such as a room or a series of rooms. The extent of such design need only demonstrate compliance of the nonconventional light-framed elements with other applicable provisions of this code and shall be compatible with the performance of the conventional light-framed system.
Connectors and fasteners used in conventional construction shall comply with the requirements of Section 2304.10.
Buildings are permitted to be constructed in accordance with the provisions of conventional light-frame construction, subject to the limitations in Sections 2308.2.1 through 2308.2.6.
Structures of conventional light-frame construction shall be limited in story height in accordance with Table 2308.2.1.
ALLOWABLE STORY HEIGHT
| SEISMIC DESIGN CATEGORY | ALLOWABLE STORY ABOVE GRADE PLANE |
| A and B | Three stories |
| C | Two stories |
| D and Ea | One story |
For SI: 1 inch = 25.4 mm.
- For the purposes of this section, for buildings assigned to Seismic Design Category D or E, cripple walls shall be considered to be a story unless cripple walls are solid blocked and do not exceed 14 inches in height.
Loads shall be in accordance with Chapter 16 and shall not exceed the following:
Average dead loads shall not exceed 15 psf (718 N/m2) for combined roof and ceiling, exterior walls, floors and partitions.
Exceptions:
- Subject to the limitations of Section 2308.6.10, stone or masonry veneer up to the lesser of 5 inches (127 mm) thick or 50 psf (2395 N/m2) and installed in accordance with Chapter 14 is permitted to a height of 30 feet (9144 mm) above a noncombustible foundation, with an additional 8 feet (2438 mm) permitted for gable ends.
- Concrete or masonry fireplaces, heaters and chimneys shall be permitted in accordance with the provisions of this code.
Live loads shall not exceed 40 psf (1916 N/m2) for floors.
Exception: Live loads for concrete slab-on-ground floors in Risk Categories I and II shall be not more than 125 psf.
- Ground snow loads shall not exceed 50 psf (2395 N/m2).
V shall not exceed 130 miles per hour (57 m/s) (3-second gust).
Exceptions:
- V shall not exceed 140 mph (61.6 m/s) (3-second gust) for buildings in Exposure Category B that are not located in a hurricane-prone region.
- Where V exceeds 130 mph (3-second gust), the provisions of either AWC WFCM or ICC 600 are permitted to be used.
Ceiling joist and rafter framing constructed in accordance with Section 2308.7 and trusses shall not span more than 40 feet (12 192 mm) between points of vertical support. A ridge board in accordance with Section 2308.7 or 2308.7.3.1 shall not be considered a vertical support.
The use of the provisions for conventional light-frame construction in this section shall not be permitted for Risk Category IV buildings assigned to Seismic Design Category B, C, D or F.
[DSA-SS & DSA-SS/CC and OSHPD 1R, 2 & 5] The use of conventional light-frame
construction provisions in this section is permitted,
subject to the following conditions:
- The design and construction shall also comply with Section 2304 and Section 2305.
- In conjunction with the use of provisions in Section 2308.6 (Wall bracing), engineering analysis shall be furnished that demonstrates compliance of lateral-force-resisting systems with Section 2305.
- In addition to the use of provisions in Section 2308.4 (Floor framing), engineering analysis shall be furnished that demonstrates compliance of floor framing elements and connections with Section 2302.1, Item 1 or 2.
- In addition to the use of provisions in Section 2308.5 (Wall construction), engineering analysis shall be furnished that demonstrates compliance of wall framing elements and connections with Section 2302.1, Item 1 or 2.
- In addition to the use of provisions in Section 2308.7 (Roof and Ceiling Framing), engineering analysis shall be furnished demonstrating compliance of roof and ceiling framing elements and connections with Section 2302.1, Item 1 or 2.
Foundations and footings shall be designed and constructed in accordance with Chapter 18. Connections to foundations and footings shall comply with this section.
Foundation plates or sills resting on concrete or masonry foundations shall comply with Section 2304.3.1. Foundation plates or sills shall be bolted or anchored to the foundation with not less than 1/2-inch-diameter (12.7 mm) steel bolts or approved anchors spaced to provide equivalent anchorage as the steel bolts. Bolts shall be embedded not less than 7 inches (178 mm) into concrete or masonry. The bolts shall be located in the middle third of the width of the plate. Bolts shall be spaced not more than 6 feet (1829 mm) on center and there shall be not less than two bolts or anchor straps per piece with one bolt or anchor strap located not more than 12 inches (305 mm) or less than 4 inches (102 mm) from each end of each piece. Bolts in sill plates of braced wall lines in structures over two stories above grade shall be spaced not more than 4 feet (1219 mm) on center. A properly sized nut and washer shall be tightened on each bolt to the plate.
Sill plates along braced wall lines in buildings assigned to Seismic Design Category D shall be anchored with not less than 1/2-inch (12.7 mm) diameter anchor bolts with steel plate washers between the foundation sill plate and the nut, or approved anchor straps load-rated in accordance with Section 2304.10.3 and spaced to provide equivalent anchorage. Plate washers shall be not less than 0.229 inch by 3 inches by 3 inches (5.82 mm by 76 mm by 76 mm) in size. The hole in the plate washer is permitted to be diagonally slotted with a width of up to 3/16 inch (4.76 mm) larger than the bolt diameter and a slot length not to exceed 13/4 inches (44 mm), provided that a standard cut washer is placed between the plate washer and the nut.
Sill plates along braced wall lines in buildings assigned to Seismic Design Category E shall be anchored with not less than 5/8-inch diameter (15.9 mm) anchor bolts with steel plate washers between the foundation sill plate and the nut, or approved anchor straps load-rated in accordance with Section 2304.10.3 and spaced to provide equivalent anchorage. Plate washers shall be not less than 0.229 inch by 3 inches by 3 inches (5.82 mm by 76 mm by 76 mm) in size. The hole in the plate washer is permitted to be diagonally slotted with a width of up to 3/16 inch (4.76 mm) larger than the bolt diameter and a slot length not to exceed 13/4 inches (44 mm), provided that a standard cut washer is placed between the plate washer and the nut.
Floor framing shall comply with this section.
Girders for single-story construction or girders supporting loads from a single floor shall be not less than 4 inches by 6 inches (102 mm by 152 mm) for spans 6 feet (1829 mm) or less, provided that girders are spaced not more than 8 feet (2438 mm) on center. Other girders shall be designed to support the loads specified in this code. Girder end joints shall occur over supports.
Where a girder is spliced over a support, an adequate tie shall be provided. The ends of beams or girders supported on masonry or concrete shall not have less than 3 inches (76 mm) of bearing.
The allowable spans of girders that are fabricated of dimension lumber shall not exceed the values set forth in Table 2308.4.1.1(1) or 2308.4.1.1(2).
HEADER AND GIRDER SPANSa, b FOR EXTERIOR BEARING WALLS (Maximum spans for Douglas fir-larch, hem-fir, Southern pine and spruce-pine-fir and required number of jack studs)
| GIRDERS AND HEADERS SUPPORTING | SIZE | GROUND SNOW LOAD (psf)e | |||||||||||||||||
| 30 | 50 | 70 | |||||||||||||||||
| Building widthc (feet) | |||||||||||||||||||
| 12 | 24 | 36 | 12 | 24 | 36 | 12 | 24 | 36 | |||||||||||
| Spanf | NJd | Spanf | NJd | Spanf | NJd | Spanf | NJd | Spanf | NJd | Spanf | NJd | Spanf | NJd | Spanf | NJd | Spanf | NJd | ||
| Roof and ceiling | 1-2 × 6 | 4-0 | 1 | 3-1 | 2 | 2-7 | 2 | 3-5 | 1 | 2-8 | 2 | 2-3 | 2 | 3-0 | 2 | 2-4 | 2 | 2-0 | 2 |
| 1-2 × 8 | 5-1 | 2 | 3-11 | 2 | 3-3 | 2 | 4-4 | 2 | 3-4 | 2 | 2-10 | 2 | 3-10 | 2 | 3-0 | 2 | 2-6 | 3 | |
| 1-2 × 10 | 6-0 | 2 | 4-8 | 2 | 3-11 | 2 | 5-2 | 2 | 4-0 | 2 | 3-4 | 3 | 4-7 | 2 | 3-6 | 3 | 3-0 | 3 | |
| 1-2 × 12 | 7-1 | 2 | 5-5 | 2 | 4-7 | 3 | 6-1 | 2 | 4-8 | 3 | 3-11 | 3 | 5-5 | 2 | 4-2 | 3 | 3-6 | 3 | |
| 2-2 × 4 | 4-0 | 1 | 3-1 | 1 | 2-7 | 1 | 3-5 | 1 | 2-7 | 1 | 2-2 | 1 | 3-0 | 1 | 2-4 | 1 | 2-0 | 1 | |
| 2-2 × 6 | 6-0 | 1 | 4-7 | 1 | 3-10 | 1 | 5-1 | 1 | 3-11 | 1 | 3-3 | 2 | 4-6 | 1 | 3-6 | 2 | 2-11 | 2 | |
| 2-2 × 8 | 7-7 | 1 | 5-9 | 1 | 4-10 | 2 | 6-5 | 1 | 5-0 | 2 | 4-2 | 2 | 5-9 | 1 | 4-5 | 2 | 3-9 | 2 | |
| 2-2 × 10 | 9-0 | 1 | 6-10 | 2 | 5-9 | 2 | 7-8 | 2 | 5-11 | 2 | 4-11 | 2 | 6-9 | 2 | 5-3 | 2 | 4-5 | 2 | |
| 2-2 × 12 | 10-7 | 2 | 8-1 | 2 | 6-10 | 2 | 9-0 | 2 | 6-11 | 2 | 5-10 | 2 | 8-0 | 2 | 6-2 | 2 | 5-2 | 3 | |
| 3-2 × 8 | 9-5 | 1 | 7-3 | 1 | 6-1 | 1 | 8-1 | 1 | 6-3 | 1 | 5-3 | 2 | 7-2 | 1 | 5-6 | 2 | 4-8 | 2 | |
| 3-2 × 10 | 11-3 | 1 | 8-7 | 1 | 7-3 | 2 | 9-7 | 1 | 7-4 | 2 | 6-2 | 2 | 8-6 | 1 | 6-7 | 2 | 5-6 | 2 | |
| 3-2 × 12 | 13-2 | 1 | 10-1 | 2 | 8-6 | 2 | 11-3 | 2 | 8-8 | 2 | 7-4 | 2 | 10-0 | 2 | 7-9 | 2 | 6-6 | 2 | |
| 4-2 × 8 | 10-11 | 1 | 8-4 | 1 | 7-0 | 1 | 9-4 | 1 | 7-2 | 1 | 6-0 | 1 | 8-3 | 1 | 6-4 | 1 | 5-4 | 2 | |
| 4-2 × 10 | 12-11 | 1 | 9-11 | 1 | 8-4 | 1 | 11-1 | 1 | 8-6 | 1 | 7-2 | 2 | 9-10 | 1 | 7-7 | 2 | 6-4 | 2 | |
| 4-2 × 12 | 15-3 | 1 | 11-8 | 1 | 9-10 | 2 | 13-0 | 1 | 10-0 | 2 | 8-5 | 2 | 11-7 | 1 | 8-11 | 2 | 7-6 | 2 | |
| Roof, ceiling and one center-bearing floor | 1-2 × 6 | 3-3 | 1 | 2-7 | 2 | 2-2 | 2 | 3-0 | 2 | 2-4 | 2 | 2-0 | 2 | 2-9 | 2 | 2-2 | 2 | 1-10 | 2 |
| 1-2 × 8 | 4-1 | 2 | 3-3 | 2 | 2-9 | 2 | 3-9 | 2 | 3-0 | 2 | 2-6 | 3 | 3-6 | 2 | 2-9 | 2 | 2-4 | 3 | |
| 1-2 × 10 | 4-11 | 2 | 3-10 | 2 | 3-3 | 3 | 4-6 | 2 | 3-6 | 3 | 3-0 | 3 | 4-1 | 2 | 3-3 | 3 | 2-9 | 3 | |
| 1-2 × 12 | 5-9 | 2 | 4-6 | 3 | 3-10 | 3 | 5-3 | 2 | 4-2 | 3 | 3-6 | 3 | 4-10 | 3 | 3-10 | 3 | 3-3 | 4 | |
| 2-2 × 4 | 3-3 | 1 | 2-6 | 1 | 2-2 | 1 | 3-0 | 1 | 2-4 | 1 | 2-0 | 1 | 2-8 | 1 | 2-2 | 1 | 1-10 | 1 | |
| 2-2 × 6 | 4-10 | 1 | 3-9 | 1 | 3-3 | 2 | 4-5 | 1 | 3-6 | 2 | 3-0 | 2 | 4-1 | 1 | 3-3 | 2 | 2-9 | 2 | |
| 2-2 × 8 | 6-1 | 1 | 4-10 | 2 | 4-1 | 2 | 5-7 | 2 | 4-5 | 2 | 3-9 | 2 | 5-2 | 2 | 4-1 | 2 | 3-6 | 2 | |
| 2-2 × 10 | 7-3 | 2 | 5-8 | 2 | 4-10 | 2 | 6-8 | 2 | 5-3 | 2 | 4-5 | 2 | 6-1 | 2 | 4-10 | 2 | 4-1 | 2 | |
| 2-2 × 12 | 8-6 | 2 | 6-8 | 2 | 5-8 | 2 | 7-10 | 2 | 6-2 | 2 | 5-3 | 3 | 7-2 | 2 | 5-8 | 2 | 4-10 | 3 | |
| 3-2 × 8 | 7-8 | 1 | 6-0 | 1 | 5-1 | 2 | 7-0 | 1 | 5-6 | 2 | 4-8 | 2 | 6-5 | 1 | 5-1 | 2 | 4-4 | 2 | |
| 3-2 × 10 | 9-1 | 1 | 7-2 | 2 | 6-1 | 2 | 8-4 | 1 | 6-7 | 2 | 5-7 | 2 | 7-8 | 2 | 6-1 | 2 | 5-2 | 2 | |
| 3-2 × 12 | 10-8 | 2 | 8-5 | 2 | 7-2 | 2 | 9-10 | 2 | 7-8 | 2 | 6-7 | 2 | 9-0 | 2 | 7-1 | 2 | 6-1 | 2 | |
| 4-2 × 8 | 8-10 | 1 | 6-11 | 1 | 5-11 | 1 | 8-1 | 1 | 6-4 | 1 | 5-5 | 2 | 7-5 | 1 | 5-11 | 1 | 5-0 | 2 | |
| 4-2 × 10 | 10-6 | 1 | 8-3 | 2 | 7-0 | 2 | 9-8 | 1 | 7-7 | 2 | 6-5 | 2 | 8-10 | 1 | 7-0 | 2 | 6-0 | 2 | |
| 4-2 × 12 | 12-4 | 1 | 9-8 | 2 | 8-3 | 2 | 11-4 | 2 | 8-11 | 2 | 7-7 | 2 | 10-4 | 2 | 8-3 | 2 | 7-0 | 2 | |
| Roof, ceiling and one clear span floor | 1-2 × 6 | 2-11 | 2 | 2-3 | 2 | 1-11 | 2 | 2-9 | 2 | 2-1 | 2 | 1-9 | 2 | 2-7 | 2 | 2-0 | 2 | 1-8 | 2 |
| 1-2 × 8 | 3-9 | 2 | 2-10 | 2 | 2-5 | 3 | 3-6 | 2 | 2-8 | 2 | 2-3 | 3 | 3-3 | 2 | 2-6 | 3 | 2-2 | 3 | |
| 1-2 × 10 | 4-5 | 2 | 3-5 | 3 | 2-10 | 3 | 4-2 | 2 | 3-2 | 3 | 2-8 | 3 | 3-11 | 2 | 3-0 | 3 | 2-6 | 3 | |
| 1-2 × 12 | 5-2 | 2 | 4-0 | 3 | 3-4 | 3 | 4-10 | 3 | 3-9 | 3 | 3-2 | 4 | 4-7 | 3 | 3-6 | 3 | 3-0 | 4 | |
| 2-2 × 4 | 2-11 | 1 | 2-3 | 1 | 1-10 | 1 | 2-9 | 1 | 2-1 | 1 | 1-9 | 1 | 2-7 | 1 | 2-0 | 1 | 1-8 | 1 | |
| 2-2 × 6 | 4-4 | 1 | 3-4 | 2 | 2-10 | 2 | 4-1 | 1 | 3-2 | 2 | 2-8 | 2 | 3-10 | 1 | 3-0 | 2 | 2-6 | 2 | |
| 2-2 × 8 | 5-6 | 2 | 4-3 | 2 | 3-7 | 2 | 5-2 | 2 | 4-0 | 2 | 3-4 | 2 | 4-10 | 2 | 3-9 | 2 | 3-2 | 2 | |
| 2-2 × 10 | 6-7 | 2 | 5-0 | 2 | 4-2 | 2 | 6-1 | 2 | 4-9 | 2 | 4-0 | 2 | 5-9 | 2 | 4-5 | 2 | 3-9 | 3 | |
| 2-2 × 12 | 7-9 | 2 | 5-11 | 2 | 4-11 | 3 | 7-2 | 2 | 5-7 | 2 | 4-8 | 3 | 6-9 | 2 | 5-3 | 3 | 4-5 | 3 | |
| 3-2 × 8 | 6-11 | 1 | 5-3 | 2 | 4-5 | 2 | 6-5 | 1 | 5-0 | 2 | 4-2 | 2 | 6-1 | 1 | 4-8 | 2 | 4-0 | 2 | |
| 3-2 × 10 | 8-3 | 2 | 6-3 | 2 | 5-3 | 2 | 7-8 | 2 | 5-11 | 2 | 5-0 | 2 | 7-3 | 2 | 5-7 | 2 | 4-8 | 2 | |
| 3-2 × 12 | 9-8 | 2 | 7-5 | 2 | 6-2 | 2 | 9-0 | 2 | 7-0 | 2 | 5-10 | 2 | 8-6 | 2 | 6-7 | 2 | 5-6 | 3 | |
| 4-2 × 8 | 8-0 | 1 | 6-1 | 1 | 5-1 | 2 | 7-5 | 1 | 5-9 | 2 | 4-10 | 2 | 7-0 | 1 | 5-5 | 2 | 4-7 | 2 | |
| 4-2 × 10 | 9-6 | 1 | 7-3 | 2 | 6-1 | 2 | 8-10 | 1 | 6-10 | 2 | 5-9 | 2 | 8-4 | 1 | 6-5 | 2 | 5-5 | 2 | |
| 4-2 × 12 | 11-2 | 2 | 8-6 | 2 | 7-2 | 2 | 10-5 | 2 | 8-0 | 2 | 6-9 | 2 | 9-10 | 2 | 7-7 | 2 | 6-5 | 2 | |
| Roof, ceiling and two center-bearing floors | 1-2 × 6 | 2-8 | 2 | 2-1 | 2 | 1-10 | 2 | 2-7 | 2 | 2-0 | 2 | 1-9 | 2 | 2-5 | 2 | 1-11 | 2 | 1-8 | 2 |
| 1-2 × 8 | 3-5 | 2 | 2-8 | 2 | 2-4 | 3 | 3-3 | 2 | 2-7 | 2 | 2-2 | 3 | 3-1 | 2 | 2-5 | 3 | 2-1 | 3 | |
| 1-2 × 10 | 4-0 | 2 | 3-2 | 3 | 2-9 | 3 | 3-10 | 2 | 3-1 | 3 | 2-7 | 3 | 3-8 | 2 | 2-11 | 3 | 2-5 | 3 | |
| 1-2 × 12 | 4-9 | 3 | 3-9 | 3 | 3-2 | 4 | 4-6 | 3 | 3-7 | 3 | 3-1 | 4 | 4-3 | 3 | 3-5 | 3 | 2-11 | 4 | |
| 2-2 × 4 | 2-8 | 1 | 2-1 | 1 | 1-9 | 1 | 2-6 | 1 | 2-0 | 1 | 1-8 | 1 | 2-5 | 1 | 1-11 | 1 | 1-7 | 1 | |
| 2-2 × 6 | 4-0 | 1 | 3-2 | 2 | 2-8 | 2 | 3-9 | 1 | 3-0 | 2 | 2-7 | 2 | 3-7 | 1 | 2-10 | 2 | 2-5 | 2 | |
| 2-2 × 8 | 5-0 | 2 | 4-0 | 2 | 3-5 | 2 | 4-10 | 2 | 3-10 | 2 | 3-3 | 2 | 4-7 | 2 | 3-7 | 2 | 3-1 | 2 | |
| 2-2 × 10 | 6-0 | 2 | 4-9 | 2 | 4-0 | 2 | 5-8 | 2 | 4-6 | 2 | 3-10 | 3 | 5-5 | 2 | 4-3 | 2 | 3-8 | 3 | |
| 2-2 × 12 | 7-0 | 2 | 5-7 | 2 | 4-9 | 3 | 6-8 | 2 | 5-4 | 3 | 4-6 | 3 | 6-4 | 2 | 5-0 | 3 | 4-3 | 3 | |
| 3-2 × 8 | 6-4 | 1 | 5-0 | 2 | 4-3 | 2 | 6-0 | 1 | 4-9 | 2 | 4-1 | 2 | 5-8 | 2 | 4-6 | 2 | 3-10 | 2 | |
| 3-2 × 10 | 7-6 | 2 | 5-11 | 2 | 5-1 | 2 | 7-1 | 2 | 5-8 | 2 | 4-10 | 2 | 6-9 | 2 | 5-4 | 2 | 4-7 | 2 | |
| 3-2 × 12 | 8-10 | 2 | 7-0 | 2 | 5-11 | 2 | 8-5 | 2 | 6-8 | 2 | 5-8 | 3 | 8-0 | 2 | 6-4 | 2 | 5-4 | 3 | |
| 4-2 × 8 | 7-3 | 1 | 5-9 | 1 | 4-11 | 2 | 6-11 | 1 | 5-6 | 2 | 4-8 | 2 | 6-7 | 1 | 5-2 | 2 | 4-5 | 2 | |
| 4-2 × 10 | 8-8 | 1 | 6-10 | 2 | 5-10 | 2 | 8-3 | 2 | 6-6 | 2 | 5-7 | 2 | 7-10 | 2 | 6-2 | 2 | 5-3 | 2 | |
| 4-2 × 12 | 10-2 | 2 | 8-1 | 2 | 6-10 | 2 | 9-8 | 2 | 7-8 | 2 | 6-7 | 2 | 9-2 | 2 | 7-3 | 2 | 6-2 | 2 | |
| Roof, ceiling and two clear span floors | 1-2 × 6 | 2-3 | 2 | 1-9 | 2 | 1-5 | 2 | 2-3 | 2 | 1-9 | 2 | 1-5 | 3 | 2-2 | 2 | 1-8 | 2 | 1-5 | 3 |
| 1-2 × 8 | 2-10 | 2 | 2-2 | 3 | 1-10 | 3 | 2-10 | 2 | 2-2 | 3 | 1-10 | 3 | 2-9 | 2 | 2-1 | 3 | 1-10 | 3 | |
| 1-2 × 10 | 3-4 | 2 | 2-7 | 3 | 2-2 | 3 | 3-4 | 3 | 2-7 | 3 | 2-2 | 4 | 3-3 | 3 | 2-6 | 3 | 2-2 | 4 | |
| 1-2 × 12 | 4-0 | 3 | 3-0 | 3 | 2-7 | 4 | 4-0 | 3 | 3-0 | 4 | 2-7 | 4 | 3-10 | 3 | 3-0 | 4 | 2-6 | 4 | |
| 2-2 × 4 | 2-3 | 1 | 1-8 | 1 | 1-4 | 1 | 2-3 | 1 | 1-8 | 1 | 1-4 | 1 | 2-2 | 1 | 1-8 | 1 | 1-4 | 2 | |
| 2-2 × 6 | 3-4 | 1 | 2-6 | 2 | 2-2 | 2 | 3-4 | 2 | 2-6 | 2 | 2-2 | 2 | 3-3 | 2 | 2-6 | 2 | 2-1 | 2 | |
| 2-2 × 8 | 4-3 | 2 | 3-3 | 2 | 2-8 | 2 | 4-3 | 2 | 3-3 | 2 | 2-8 | 2 | 4-1 | 2 | 3-2 | 2 | 2-8 | 3 | |
| 2-2 × 10 | 5-0 | 2 | 3-10 | 2 | 3-2 | 3 | 5-0 | 2 | 3-10 | 2 | 3-2 | 3 | 4-10 | 2 | 3-9 | 3 | 3-2 | 3 | |
| 2-2 × 12 | 5-11 | 2 | 4-6 | 3 | 3-9 | 3 | 5-11 | 2 | 4-6 | 3 | 3-9 | 3 | 5-8 | 2 | 4-5 | 3 | 3-9 | 3 | |
| 3-2 × 8 | 5-3 | 1 | 4-0 | 2 | 3-5 | 2 | 5-3 | 2 | 4-0 | 2 | 3-5 | 2 | 5-1 | 2 | 3-11 | 2 | 3-4 | 2 | |
| 3-2 × 10 | 6-3 | 2 | 4-9 | 2 | 4-0 | 2 | 6-3 | 2 | 4-9 | 2 | 4-0 | 2 | 6-1 | 2 | 4-8 | 2 | 4-0 | 3 | |
| 3-2 × 12 | 7-5 | 2 | 5-8 | 2 | 4-9 | 3 | 7-5 | 2 | 5-8 | 2 | 4-9 | 3 | 7-2 | 2 | 5-6 | 3 | 4-8 | 3 | |
| 4-2 × 8 | 6-1 | 1 | 4-8 | 2 | 3-11 | 2 | 6-1 | 1 | 4-8 | 2 | 3-11 | 2 | 5-11 | 1 | 4-7 | 2 | 3-10 | 2 | |
| 4-2 × 10 | 7-3 | 2 | 5-6 | 2 | 4-8 | 2 | 7-3 | 2 | 5-6 | 2 | 4-8 | 2 | 7-0 | 2 | 5-5 | 2 | 4-7 | 2 | |
| 4-2 × 12 | 8-6 | 2 | 6-6 | 2 | 5-6 | 2 | 8-6 | 2 | 6-6 | 2 | 5-6 | 2 | 8-3 | 2 | 6-4 | 2 | 5-4 | 3 | |
For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa.
- Spans are given in feet and inches.
- Spans are based on minimum design properties for No. 2 grade lumber of Douglas fir-larch, hem-fir, Southern pine and spruce-pine fir.
- Building width is measured perpendicular to the ridge. For widths between those shown, spans are permitted to be interpolated.
- NJ = Number of jack studs required to support each end. Where the number of required jack studs equals one, the header is permitted to be supported by an approved framing anchor attached to the full-height wall stud and to the header.
- Use 30 psf ground snow load for cases in which ground snow load is less than 30 psf and the roof live load is equal to or less than 20 psf.
- Spans are calculated assuming the top of the header or girder is laterally braced by perpendicular framing. Where the top of the header or girder is not laterally braced (for example, cripple studs bearing on the header), tabulated spans for headers consisting of 2 × 8, 2 × 10, or 2 × 12 sizes shall be multiplied by 0.70 or the header or girder shall be designed.
HEADER AND GIRDER SPANSa, b FOR INTERIOR BEARING WALLS (Maximum spans for Douglas fir-larch, hem-fir, Southern pine and spruce-pine-fir and required number of jack studs)
| HEADERS AND GIRDERS SUPPORTING | SIZE | BUILDING WIDTHc (feet) | |||||
| 12 | 24 | 36 | |||||
| Spane | NJd | Spane | NJd | Spane | NJd | ||
| One floor only | 2-2 × 4 | 4-1 | 1 | 2-10 | 1 | 2-4 | 1 |
| 2-2 × 6 | 6-1 | 1 | 4-4 | 1 | 3-6 | 1 | |
| 2-2 × 8 | 7-9 | 1 | 5-5 | 1 | 4-5 | 2 | |
| 2-2 × 10 | 9-2 | 1 | 6-6 | 2 | 5-3 | 2 | |
| 2-2 × 12 | 10-9 | 1 | 7-7 | 2 | 6-3 | 2 | |
| 3-2 × 8 | 9-8 | 1 | 6-10 | 1 | 5-7 | 1 | |
| 3-2 × 10 | 11-5 | 1 | 8-1 | 1 | 6-7 | 2 | |
| 3-2 × 12 | 13-6 | 1 | 9-6 | 2 | 7-9 | 2 | |
| 4-2 × 8 | 11-2 | 1 | 7-11 | 1 | 6-5 | 1 | |
| 4-2 × 10 | 13-3 | 1 | 9-4 | 1 | 7-8 | 1 | |
| 4-2 × 12 | 15-7 | 1 | 11-0 | 1 | 9-0 | 2 | |
| Two floors | 2-2 × 4 | 2-7 | 1 | 1-11 | 1 | 1-7 | 1 |
| 2-2 × 6 | 3-11 | 1 | 2-11 | 2 | 2-5 | 2 | |
| 2-2 × 8 | 5-0 | 1 | 3-8 | 2 | 3-1 | 2 | |
| 2-2 × 10 | 5-11 | 2 | 4-4 | 2 | 3-7 | 2 | |
| 2-2 × 12 | 6-11 | 2 | 5-2 | 2 | 4-3 | 3 | |
| 3-2 × 8 | 6-3 | 1 | 4-7 | 2 | 3-10 | 2 | |
| 3-2 × 10 | 7-5 | 1 | 5-6 | 2 | 4-6 | 2 | |
| 3-2 × 12 | 8-8 | 2 | 6-5 | 2 | 5-4 | 2 | |
| 4-2 × 8 | 7-2 | 1 | 5-4 | 1 | 4-5 | 2 | |
| 4-2 × 10 | 8-6 | 1 | 6-4 | 2 | 5-3 | 2 | |
| 4-2 × 12 | 10-1 | 1 | 7-5 | 2 | 6-2 | 2 | |
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
- Spans are given in feet and inches.
- Spans are based on minimum design properties for No. 2 grade lumber of Douglas fir-larch, hem-fir, Southern pine and spruce-pine fir.
- Building width is measured perpendicular to the ridge. For widths between those shown, spans are permitted to be interpolated.
- NJ = Number of jack studs required to support each end. Where the number of required jack studs equals one, the header is permitted to be supported by an approved framing anchor attached to the full-height wall stud and to the header.
- Spans are calculated assuming the top of the header or girder is laterally braced by perpendicular framing. Where the top of the header or girder is not laterally braced (for example, cripple studs bearing on the header), tabulated spans for headers consisting of 2 × 8, 2 × 10, or 2 × 12 sizes shall be multiplied by 0.70 or the header or girder shall be designed.
Floor joists shall comply with this section.
Spans for floor joists shall be in accordance with Table 2308.4.2.1(1) or 2308.4.2.1(2) or the AWC STJR.
FLOOR JOIST SPANS FOR COMMON LUMBER SPECIES (Residential sleeping areas, live load = 30 psf, L/Δ = 360)
| JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 psf | DEAD LOAD = 20 psf | |||||||
| 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum floor joist spans | ||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 12-6 | 16-6 | 21-0 | 25-7 | 12-6 | 16-6 | 21-0 | 25-7 |
| Douglas Fir-Larch | #1 | 12-0 | 15-10 | 20-3 | 24-8 | 12-0 | 15-7 | 19-0 | 22-0 | |
| Douglas Fir-Larch | #2 | 11-10 | 15-7 | 19-10 | 23-0 | 11-6 | 14-7 | 17-9 | 20-7 | |
| Douglas Fir-Larch | #3 | 9-8 | 12-4 | 15-0 | 17-5 | 8-8 | 11-0 | 13-5 | 15-7 | |
| Hem-Fir | SS | 11-10 | 15-7 | 19-10 | 24-2 | 11-10 | 15-7 | 19-10 | 24-2 | |
| Hem-Fir | #1 | 11-7 | 15-3 | 19-5 | 23-7 | 11-7 | 15-2 | 18-6 | 21-6 | |
| Hem-Fir | #2 | 11-0 | 14-6 | 18-6 | 22-6 | 11-0 | 14-4 | 17-6 | 20-4 | |
| Hem-Fir | #3 | 9-8 | 12-4 | 15-0 | 17-5 | 8-8 | 11-0 | 13-5 | 15-7 | |
| Southern Pine | SS | 12-3 | 16-2 | 20-8 | 25-1 | 12-3 | 16-2 | 20-8 | 25-1 | |
| Southern Pine | #1 | 11-10 | 15-7 | 19-10 | 24-2 | 11-10 | 15-7 | 18-7 | 22-0 | |
| Southern Pine | #2 | 11-3 | 14-11 | 18-1 | 21-4 | 10-9 | 13-8 | 16-2 | 19-1 | |
| Southern Pine | #3 | 9-2 | 11-6 | 14-0 | 16-6 | 8-2 | 10-3 | 12-6 | 14-9 | |
| Spruce-Pine-Fir | SS | 11-7 | 15-3 | 19-5 | 23-7 | 11-7 | 15-3 | 19-5 | 23-7 | |
| Spruce-Pine-Fir | #1 | 11-3 | 14-11 | 19-0 | 23-0 | 11-3 | 14-7 | 17-9 | 20-7 | |
| Spruce-Pine-Fir | #2 | 11-3 | 14-11 | 19-0 | 23-0 | 11-3 | 14-7 | 17-9 | 20-7 | |
| Spruce-Pine-Fir | #3 | 9-8 | 12-4 | 15-0 | 17-5 | 8-8 | 11-0 | 13-5 | 15-7 | |
| 16 | Douglas Fir-Larch | SS | 11-4 | 15-0 | 19-1 | 23-3 | 11-4 | 15-0 | 19-1 | 23-0 |
| Douglas Fir-Larch | #1 | 10-11 | 14-5 | 18-5 | 21-4 | 10-8 | 13-6 | 16-5 | 19-1 | |
| Douglas Fir-Larch | #2 | 10-9 | 14-1 | 17-2 | 19-11 | 9-11 | 12-7 | 15-5 | 17-10 | |
| Douglas Fir-Larch | #3 | 8-5 | 10-8 | 13-0 | 15-1 | 7-6 | 9-6 | 11-8 | 13-6 | |
| Hem-Fir | SS | 10-9 | 14-2 | 18-0 | 21-11 | 10-9 | 14-2 | 18-0 | 21-11 | |
| Hem-Fir | #1 | 10-6 | 13-10 | 17-8 | 20-9 | 10-4 | 13-1 | 16-0 | 18-7 | |
| Hem-Fir | #2 | 10-0 | 13-2 | 16-10 | 19-8 | 9-10 | 12-5 | 15-2 | 17-7 | |
| Hem-Fir | #3 | 8-5 | 10-8 | 13-0 | 15-1 | 7-6 | 9-6 | 11-8 | 13-6 | |
| Southern Pine | SS | 11-2 | 14-8 | 18-9 | 22-10 | 11-2 | 14-8 | 18-9 | 22-10 | |
| Southern Pine | #1 | 10-9 | 14-2 | 18-0 | 21-4 | 10-9 | 13-9 | 16-1 | 19-1 | |
| Southern Pine | #2 | 10-3 | 13-3 | 15-8 | 18-6 | 9-4 | 11-10 | 14-0 | 16-6 | |
| Southern Pine | #3 | 7-11 | 10-10 | 12-1 | 14-4 | 7-1 | 8-11 | 10-10 | 12-10 | |
| Spruce-Pine-Fir | SS | 10-6 | 13-10 | 17-8 | 21-6 | 10-6 | 13-10 | 17-8 | 21-4 | |
| Spruce-Pine-Fir | #1 | 10-3 | 13-6 | 17-2 | 19-11 | 9-11 | 12-7 | 15-5 | 17-10 | |
| Spruce-Pine-Fir | #2 | 10-3 | 13-6 | 17-2 | 19-11 | 9-11 | 12-7 | 15-5 | 17-10 | |
| Spruce-Pine-Fir | #3 | 8-5 | 10-8 | 13-0 | 15-1 | 7-6 | 9-6 | 11-8 | 13-6 | |
| 19.2 | Douglas Fir-Larch | SS | 10-8 | 14-1 | 18-0 | 21-10 | 10-8 | 14-1 | 18-0 | 21-0 |
| Douglas Fir-Larch | #1 | 10-4 | 13-7 | 16-9 | 19-6 | 9-8 | 12-4 | 15-0 | 17-5 | |
| Douglas Fir-Larch | #2 | 10-1 | 12-10 | 15-8 | 18-3 | 9-1 | 11-6 | 14-1 | 16-3 | |
| Douglas Fir-Larch | #3 | 7-8 | 9-9 | 11-10 | 13-9 | 6-10 | 8-8 | 10-7 | 12-4 | |
| Hem-Fir | SS | 10-1 | 13-4 | 17-0 | 20-8 | 10-1 | 13-4 | 17-0 | 20-7 | |
| Hem-Fir | #1 | 9-10 | 13-0 | 16-4 | 19-0 | 9-6 | 12-0 | 14-8 | 17-0 | |
| Hem-Fir | #2 | 9-5 | 12-5 | 15-6 | 17-1 | 8-11 | 11-4 | 13-10 | 16-1 | |
| Hem-Fir | #3 | 7-8 | 9-9 | 11-10 | 13-9 | 6-10 | 8-8 | 10-7 | 12-4 | |
| Southern Pine | SS | 10-6 | 13-10 | 17-8 | 21-6 | 10-6 | 13-10 | 17-8 | 21-6 | |
| Southern Pine | #1 | 10-1 | 13-4 | 16-5 | 19-6 | 9-11 | 12-7 | 14-8 | 17-5 | |
| Southern Pine | #2 | 9-6 | 12-1 | 14-4 | 16-10 | 8-6 | 10-10 | 12-10 | 15-1 | |
| Southern Pine | #3 | 7-3 | 9-1 | 11-0 | 13-1 | 6-5 | 8-2 | 9-10 | 11-8 | |
| Spruce-Pine-Fir | SS | 9-10 | 13-0 | 16-7 | 20-2 | 9-10 | 13-0 | 16-7 | 19-6 | |
| Spruce-Pine-Fir | #1 | 9-8 | 12-9 | 15-8 | 18-3 | 9-1 | 11-6 | 14-1 | 16-3 | |
| Spruce-Pine-Fir | #2 | 9-8 | 12-9 | 15-8 | 18-3 | 9-1 | 11-6 | 14-1 | 16-3 | |
| Spruce-Pine-Fir | #3 | 7-8 | 9-9 | 11-10 | 13-9 | 6-10 | 8-8 | 10-7 | 12-4 | |
| 24 | Douglas Fir-Larch | SS | 9-11 | 13-1 | 16-8 | 20-3 | 9-11 | 13-1 | 16-2 | 18-9 |
| Douglas Fir-Larch | #1 | 9-7 | 12-4 | 15-0 | 17-5 | 8-8 | 11-0 | 13-5 | 15-7 | |
| Douglas Fir-Larch | #2 | 9-1 | 11-6 | 14-1 | 16-3 | 8-1 | 10-3 | 12-7 | 14-7 | |
| Douglas Fir-Larch | #3 | 6-10 | 8-8 | 10-7 | 12-4 | 6-2 | 7-9 | 9-6 | 11-0 | |
| Hem-Fir | SS | 9-4 | 12-4 | 15-9 | 19-2 | 9-4 | 12-4 | 15-9 | 18-5 | |
| Hem-Fir | #1 | 9-2 | 12-0 | 14-8 | 17-0 | 8-6 | 10-9 | 13-1 | 15-2 | |
| Hem-Fir | #2 | 8-9 | 11-4 | 13-10 | 16-1 | 8-0 | 10-2 | 12-5 | 14-4 | |
| Hem-Fir | #3 | 6-10 | 8-8 | 10-7 | 12-4 | 6-2 | 7-9 | 9-6 | 11-0 | |
| Southern Pine | SS | 9-9 | 12-10 | 16-5 | 19-11 | 9-9 | 12-10 | 16-5 | 19-8 | |
| Southern Pine | #1 | 9-4 | 12-4 | 14-8 | 17-5 | 8-10 | 11-3 | 13-1 | 15-7 | |
| Southern Pine | #2 | 8-6 | 10-10 | 12-10 | 15-1 | 7-7 | 9-8 | 11-5 | 13-6 | |
| Southern Pine | #3 | 6-5 | 8-2 | 9-10 | 11-8 | 5-9 | 7-3 | 8-10 | 10-5 | |
| Spruce-Pine-Fir | SS | 9-2 | 12-1 | 15-5 | 18-9 | 9-2 | 12-1 | 15-0 | 17-5 | |
| Spruce-Pine-Fir | #1 | 8-11 | 11-6 | 14-1 | 16-3 | 8-1 | 10-3 | 12-7 | 14-7 | |
| Spruce-Pine-Fir | #2 | 8-11 | 11-6 | 14-1 | 16-3 | 8-1 | 10-3 | 12-7 | 14-7 | |
| Spruce-Pine-Fir | #3 | 6-10 | 8-8 | 10-7 | 12-4 | 6-2 | 7-9 | 9-6 | 11-0 | |
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
Note: Check sources for availability of lumber in lengths greater than 20 feet.
FLOOR JOIST SPANS FOR COMMON LUMBER SPECIES (Residential living areas, live load = 40 psf, L/Δ = 360)
| JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 10 psf | DEAD LOAD = 20 psf | |||||||
| 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | 2 × 6 | 2 × 8 | 2 × 10 | 2 × 12 | |||
| Maximum floor joist spans | ||||||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 11-4 | 15-0 | 19-1 | 23-3 | 11-4 | 15-0 | 19-1 | 23-3 |
| Douglas Fir-Larch | #1 | 10-11 | 14-5 | 18-5 | 22-0 | 10-11 | 14-2 | 17-4 | 20-1 | |
| Douglas Fir-Larch | #2 | 10-9 | 14-2 | 17-9 | 20-7 | 10-6 | 13-3 | 16-3 | 18-10 | |
| Douglas Fir-Larch | #3 | 8-8 | 11-0 | 13-5 | 15-7 | 7-11 | 10-0 | 12-3 | 14-3 | |
| Hem-Fir | SS | 10-9 | 14-2 | 18-0 | 21-11 | 10-9 | 14-2 | 18-0 | 21-11 | |
| Hem-Fir | #1 | 10-6 | 13-10 | 17-8 | 21-6 | 10-6 | 13-10 | 16-11 | 19-7 | |
| Hem-Fir | #2 | 10-0 | 13-2 | 16-10 | 20-4 | 10-0 | 13-1 | 16-0 | 18-6 | |
| Hem-Fir | #3 | 8-8 | 11-0 | 13-5 | 15-7 | 7-11 | 10-0 | 12-3 | 14-3 | |
| Southern Pine | SS | 11-2 | 14-8 | 18-9 | 22-10 | 11-2 | 14-8 | 18-9 | 22-10 | |
| Southern Pine | #1 | 10-9 | 14-2 | 18-0 | 21-11 | 10-9 | 14-2 | 16-11 | 20-1 | |
| Southern Pine | #2 | 10-3 | 13-6 | 16-2 | 19-1 | 9-10 | 12-6 | 14-9 | 17-5 | |
| Southern Pine | #3 | 8-2 | 10-3 | 12-6 | 14-9 | 7-5 | 9-5 | 11-5 | 13-6 | |
| Spruce-Pine-Fir | SS | 10-6 | 13-10 | 17-8 | 21-6 | 10-6 | 13-10 | 17-8 | 21-6 | |
| Spruce-Pine-Fir | #1 | 10-3 | 13-6 | 17-3 | 20-7 | 10-3 | 13-3 | 16-3 | 18-10 | |
| Spruce-Pine-Fir | #2 | 10-3 | 13-6 | 17-3 | 20-7 | 10-3 | 13-3 | 16-3 | 18-10 | |
| Spruce-Pine-Fir | #3 | 8-8 | 11-0 | 13-5 | 15-7 | 7-11 | 10-0 | 12-3 | 14-3 | |
| 16 | Douglas Fir-Larch | SS | 10-4 | 13-7 | 17-4 | 21-1 | 10-4 | 13-7 | 17-4 | 21-0 |
| Douglas Fir-Larch | #1 | 9-11 | 13-1 | 16-5 | 19-1 | 9-8 | 12-4 | 15-0 | 17-5 | |
| Douglas Fir-Larch | #2 | 9-9 | 12-7 | 15-5 | 17-10 | 9-1 | 11-6 | 14-1 | 16-3 | |
| Douglas Fir-Larch | #3 | 7-6 | 9-6 | 11-8 | 13-6 | 6-10 | 8-8 | 10-7 | 12-4 | |
| Hem-Fir | SS | 9-9 | 12-10 | 16-5 | 19-11 | 9-9 | 12-10 | 16-5 | 19-11 | |
| Hem-Fir | #1 | 9-6 | 12-7 | 16-0 | 18-7 | 9-6 | 12-0 | 14-8 | 17-0 | |
| Hem-Fir | #2 | 9-1 | 12-0 | 15-2 | 17-7 | 8-11 | 11-4 | 13-10 | 16-1 | |
| Hem-Fir | #3 | 7-6 | 9-6 | 11-8 | 13-6 | 6-10 | 8-8 | 10-7 | 12-4 | |
| Southern Pine | SS | 10-2 | 13-4 | 17-0 | 20-9 | 10-2 | 13-4 | 17-0 | 20-9 | |
| Southern Pine | #1 | 9-9 | 12-10 | 16-1 | 19-1 | 9-9 | 12-7 | 14-8 | 17-5 | |
| Southern Pine | #2 | 9-4 | 11-10 | 14-0 | 16-6 | 8-6 | 10-10 | 12-10 | 15-1 | |
| Southern Pine | #3 | 7-1 | 8-11 | 10-10 | 12-10 | 6-5 | 8-2 | 9-10 | 11-8 | |
| Spruce-Pine-Fir | SS | 9-6 | 12-7 | 16-0 | 19-6 | 9-6 | 12-7 | 16-0 | 19-6 | |
| Spruce-Pine-Fir | #1 | 9-4 | 12-3 | 15-5 | 17-10 | 9-1 | 11-6 | 14-1 | 16-3 | |
| Spruce-Pine-Fir | #2 | 9-4 | 12-3 | 15-5 | 17-10 | 9-1 | 11-6 | 14-1 | 16-3 | |
| Spruce-Pine-Fir | #3 | 7-6 | 9-6 | 11-8 | 13-6 | 6-10 | 8-8 | 10-7 | 12-4 | |
| 19.2 | Douglas Fir-Larch | SS | 9-8 | 12-10 | 16-4 | 19-10 | 9-8 | 12-10 | 16-4 | 19-2 |
| Douglas Fir-Larch | #1 | 9-4 | 12-4 | 15-0 | 17-5 | 8-10 | 11-3 | 13-8 | 15-11 | |
| Douglas Fir-Larch | #2 | 9-1 | 11-6 | 14-1 | 16-3 | 8-3 | 10-6 | 12-10 | 14-10 | |
| Douglas Fir-Larch | #3 | 6-10 | 8-8 | 10-7 | 12-4 | 6-3 | 7-11 | 9-8 | 11-3 | |
| Hem-Fir | SS | 9-2 | 12-1 | 15-5 | 18-9 | 9-2 | 12-1 | 15-5 | 18-9 | |
| Hem-Fir | #1 | 9-0 | 11-10 | 14-8 | 17-0 | 8-8 | 10-11 | 13-4 | 15-6 | |
| Hem-Fir | #2 | 8-7 | 11-3 | 13-10 | 16-1 | 8-2 | 10-4 | 12-8 | 14-8 | |
| Hem-Fir | #3 | 6-10 | 8-8 | 10-7 | 12-4 | 6-3 | 7-11 | 9-8 | 11-3 | |
| Southern Pine | SS | 9-6 | 12-7 | 16-0 | 19-6 | 9-6 | 12-7 | 16-0 | 19-6 | |
| Southern Pine | #1 | 9-2 | 12-1 | 14-8 | 17-5 | 9-0 | 11-5 | 13-5 | 15-11 | |
| Southern Pine | #2 | 8-6 | 10-10 | 12-10 | 15-1 | 7-9 | 9-10 | 11-8 | 13-9 | |
| Southern Pine | #3 | 6-5 | 8-2 | 9-10 | 11-8 | 5-11 | 7-5 | 9-0 | 10-8 | |
| Spruce-Pine-Fir | SS | 9-0 | 11-10 | 15-1 | 18-4 | 9-0 | 11-10 | 15-1 | 17-9 | |
| Spruce-Pine-Fir | # | 8-9 | 11-6 | 14-1 | 16-3 | 8-3 | 10-6 | 12-10 | 14-10 | |
| Spruce-Pine-Fir | #2 | 8-9 | 11-6 | 14-1 | 16-3 | 8-3 | 10-6 | 12-10 | 14-10 | |
| Spruce-Pine-Fir | #3 | 6-10 | 8-8 | 10-7 | 12-4 | 6-3 | 7-11 | 9-8 | 11-3 | |
| 24 | Douglas Fir-Larch | SS | 9-0 | 11-11 | 15-2 | 18-5 | 9-0 | 11-11 | 14-9 | 17-1 |
| Douglas Fir-Larch | #1 | 8-8 | 11-0 | 13-5 | 15-7 | 7-11 | 10-0 | 12-3 | 14-3 | |
| Douglas Fir-Larch | #2 | 8-1 | 10-3 | 12-7 | 14-7 | 7-5 | 9-5 | 11-6 | 13-4 | |
| Douglas Fir-Larch | #3 | 6-2 | 7-9 | 9-6 | 11-0 | 5-7 | 7-1 | 8-8 | 10-1 | |
| Hem-Fir | SS | 8-6 | 11-3 | 14-4 | 17-5 | 8-6 | 11-3 | 14-4 | 16-10a | |
| Hem-Fir | #1 | 8-4 | 10-9 | 13-1 | 15-2 | 7-9 | 9-9 | 11-11 | 13-10 | |
| Hem-Fir | #2 | 7-11 | 10-2 | 12-5 | 14-4 | 7-4 | 9-3 | 11-4 | 13-1 | |
| Hem-Fir | #3 | 6-2 | 7-9 | 9-6 | 11-0 | 5-7 | 7-1 | 8-8 | 10-1 | |
| Southern Pine | SS | 8-10 | 11-8 | 14-11 | 18-1 | 8-10 | 11-8 | 14-11 | 18-0 | |
| Southern Pine | #1 | 8-6 | 11-3 | 13-1 | 15-7 | 8-1 | 10-3 | 12-0 | 14-3 | |
| Southern Pine | #2 | 7-7 | 9-8 | 11-5 | 13-6 | 7-0 | 8-10 | 10-5 | 12-4 | |
| Southern Pine | #3 | 5-9 | 7-3 | 8-10 | 10-5 | 5-3 | 6-8 | 8-1 | 9-6 | |
| Spruce-Pine-Fir | SS | 8-4 | 11-0 | 14-0 | 17-0 | 8-4 | 11-0 | 13-8 | 15-11 | |
| Spruce-Pine-Fir | #1 | 8-1 | 10-3 | 12-7 | 14-7 | 7-5 | 9-5 | 11-6 | 13-4 | |
| Spruce-Pine-Fir | #2 | 8-1 | 10-3 | 12-7 | 14-7 | 7-5 | 9-5 | 11-6 | 13-4 | |
| Spruce-Pine-Fir | #3 | 6-2 | 7-9 | 9-6 | 11-0 | 5-7 | 7-1 | 8-8 | 10-1 | |
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
Note: Check sources for availability of lumber in lengths greater than 20 feet.
- End bearing length shall be increased to 2 inches.
The ends of each joist shall have not less than 11/2 inches (38 mm) of bearing on wood or metal, or not less than 3 inches (76 mm) on masonry, except where supported on a 1-inch by 4-inch (25 mm by 102 mm) ribbon strip and nailed to the adjoining stud.
Joists shall be supported laterally at the ends and at each support by solid blocking except where the ends of the joists are nailed to a header, band or rim joist or to an adjoining stud or by other means. Solid blocking shall be not less than 2 inches (51 mm) in thickness and the full depth of the joist. Joist framing from opposite sides of a beam, girder or partition shall be lapped not less than 3 inches (76 mm) or the opposing joists shall be tied together in an approved manner. Joists framing into the side of a wood girder shall be supported by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).
Notches on the ends of joists shall not exceed one-fourth the joist depth. Notches in the top or bottom of joists shall not exceed one-sixth the depth and shall not be located in the middle third of the span. Holes bored in joists shall not be within 2 inches (51 mm) of the top or bottom of the joist and the diameter of any such hole shall not exceed one-third the depth of the joist.
Engineered wood products shall be installed in accordance with manufacturer's recommendations. Cuts, notches and holes bored in trusses, structural composite lumber, structural glued-laminated members or I-joists are not permitted except where permitted by the manufacturer's recommendations or where the effects of such alterations are specifically considered in the design of the member by a registered design professional.
Trimmer and header joists shall be doubled, or of lumber of equivalent cross section, where the span of the header exceeds 4 feet (1219 mm). The ends of header joists more than 6 feet (1829 mm) in length shall be supported by framing anchors or joist hangers unless bearing on a beam, partition or wall. Tail joists over 12 feet (3658 mm) in length shall be supported at the header by framing anchors or on ledger strips not less than 2 inches by 2 inches (51 mm by 51 mm).
Openings in horizontal diaphragms in Seismic Design Categories B, C, D and E with a dimension that is greater than 4 feet (1219 mm) shall be constructed with metal ties and blocking in accordance with this section and Figure 2308.4.4.1(1). Metal ties shall be not less than 0.058 inch [1.47 mm (16 galvanized gage)] in thickness by 11/2 inches (38 mm) in width and shall have a yield stress not less than 33,000 psi (227 Mpa). Blocking shall extend not less than the dimension of the opening in the direction of the tie and blocking. Ties shall be attached to blocking in accordance with the manufacturer's instructions but with not less than eight 16d common nails on each side of the header-joist intersection.
Openings in floor diaphragms in Seismic Design Categories D and E shall not have any dimension exceeding 50 percent of the distance between braced wall lines or an area greater than 25 percent of the area between orthogonal pairs of braced wall lines [see Figure 2308.4.4.1(2)]; or the portion of the structure containing the opening shall be designed in accordance with accepted engineering practice to resist the forces specified in Chapter 16, to the extent such irregular opening affects the performance of the conventional framing system.
FIGURE 2308.4.4.1(1)
OPENINGS IN FLOOR AND ROOF DIAPHRAGMS
OPENING LIMITATIONS FOR FLOOR AND ROOF DIAPHRAGMS
In Seismic Design Categories D and E, portions of a floor level shall not be vertically offset such that the framing members on either side of the offset cannot be lapped or tied together in an approved manner in accordance with Figure 2308.4.4.2 unless the portion of the structure containing the irregular offset is designed in accordance with accepted engineering practice.
Exception: Framing supported directly by foundations need not be lapped or tied directly together.
PORTIONS OF FLOOR LEVEL OFFSET VERTICALLY
Bearing partitions parallel to joists shall be supported on beams, girders, doubled joists, walls or other bearing partitions. Bearing partitions perpendicular to joists shall not be offset from supporting girders, walls or partitions more than the joist depth unless such joists are of sufficient size to carry the additional load.
Floor and ceiling framing with a nominal depth-to-thickness ratio not less than 5 to 1 shall have one edge held in line for the entire span. Where the nominal depth-to-thickness ratio of the framing member exceeds 6 to 1, there shall be one line of bridging for each 8 feet (2438 mm) of span, unless both edges of the member are held in line. The bridging shall consist of not less than 1-inch by 3-inch (25 mm by 76 mm) lumber, double nailed at each end, or equivalent metal bracing of equal rigidity, full-depth solid blocking or other approved means. A line of bridging shall be required at supports where equivalent lateral support is not otherwise provided.
Structural floor sheathing shall comply with the provisions of Section 2304.8.1.
For under-floor ventilation, see Section 1202.4.
Where braced wall panels are supported by cantilevered floors or are set back from the floor joist support, the floor framing shall comply with Section 2308.6.7.
Exterior egress balconies, exterior stairways and ramps and similar means of egress components in structures assigned to Seismic Design Category D or E shall be positively anchored to the primary structure at not more than 8 feet (2438 mm) on center or shall be designed for lateral forces. Such attachment shall not be accomplished by use of toenails or nails subject to withdrawal.
Walls of conventional light-frame construction shall be in accordance with this section.
The size, height and spacing of studs shall be in accordance with Table 2308.5.1.
Studs shall be continuous from a support at the sole plate to a support at the top plate to resist loads perpendicular to the wall. The support shall be a foundation or floor, ceiling or roof diaphragm or shall be designed in accordance with accepted engineering practice.
Exception: Jack studs, trimmer studs and cripple studs at openings in walls that comply with Table 2308.4.1.1(1) or 2308.4.1.1(2).
SIZE, HEIGHT AND SPACING OF WOOD STUDSc
| STUD SIZE (inches) | BEARING WALLS | NONBEARING WALLS | ||||
| Laterally unsupported stud heighta (feet) | Supporting roof and ceiling only | Supporting one floor, roof and ceiling | Supporting two floors, roof and ceiling | Laterally unsupported stud heighta (feet) | Spacing (inches) | |
| Spacing (inches) | ||||||
| 2 × 3b | — | — | — | — | 10 | 16 |
| 2 × 4 | 10 | 24 | 16 | — | 14 | 24 |
| 3 × 4 | 10 | 24 | 24 | 16 | 14 | 24 |
| 2 × 5 | 10 | 24 | 24 | — | 16 | 24 |
| 2 × 6 | 10 | 24 | 24 | 16 | 20 | 24 |
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
- Listed heights are distances between points of lateral support placed perpendicular to the plane of the wall. Increases in unsupported height are permitted where justified by an analysis.
- Shall not be used in exterior walls.
- Utility-grade studs shall not be spaced more than 16 inches on center or support more than a roof and ceiling, or exceed 8 feet in height for exterior walls and load-bearing walls or 10 feet for interior nonload-bearing walls.
Studs shall be placed with their wide dimension perpendicular to the wall. Not less than three studs shall be installed at each corner of an exterior wall.
Exceptions:
- In interior nonbearing walls and partitions, studs are permitted to be set with the long dimension parallel to the wall.
- At corners, two studs are permitted, provided that wood spacers or backup cleats of 3/8-inch-thick (9.5 mm) wood structural panel, 3/8-inch (9.5 mm) Type M "Exterior Glue" particleboard, 1-inch-thick (25 mm) lumber or other approved devices that will serve as an adequate backing for the attachment of facing materials are used. Where fire-resistance ratings or shear values are involved, wood spacers, backup cleats or other devices shall not be used unless specifically approved for such use.
Studs shall have plates and sills in accordance with this section.
Bearing and exterior wall studs shall be capped with double top plates installed to provide overlapping at corners and at intersections with other partitions. End joints in double top plates shall be offset not less than 48 inches (1219 mm), and shall be nailed in accordance with Table 2304.10.1. Plates shall be a nominal 2 inches (51 mm) in depth and have a width not less than the width of the studs.
Exception: A single top plate is permitted, provided that the plate is adequately tied at corners and intersecting walls by not less than the equivalent of 3-inch by 6-inch (76 mm by 152 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d [21/2" × 0.113" (64-mm by 2.87 mm)] box nails or equivalent on each side of the joint. For the butt-joint splice between adjacent single top plates, not less than the equivalent of a 3-inch by 12-inch (76 mm by 304 mm) by 0.036-inch-thick (0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by 12 8d [21/2-inch × 0.113-inch (64 mm by 2.87 mm)] box nails on each side of the joint shall be required, provided that the rafters, joists or trusses are centered over the studs with a tolerance of not more than 1 inch (25 mm). The top plate shall not be required over headers that are in the same plane and in line with the upper surface of the adjacent top plates and are tied to adjacent wall sections as required for the butt joint splice between adjacent single top plates.
Where bearing studs are spaced at 24-inch (610 mm) intervals, top plates are less than two 2-inch by 6-inch (51 mm by 152 mm) or two 3-inch by 4-inch (76 mm by 102 mm) members and the floor joists, floor trusses or roof trusses that they support are spaced at more than 16-inch (406 mm) intervals, such joists or trusses shall bear within 5 inches (127 mm) of the studs beneath or a third plate shall be installed.
In nonload-bearing walls and partitions, that are not part of a braced wall panel, studs shall be spaced not more than 24 inches (610 mm) on center. In interior nonload-bearing walls and partitions, studs are permitted to be set with the long dimension parallel to the wall. Where studs are set with the long dimensions parallel to the wall, use of utility grade lumber or studs exceeding 10 feet (3048 mm) is not permitted. Interior nonload-bearing partitions shall be capped with not less than a single top plate installed to provide overlapping at corners and at intersections with other walls and partitions. The plate shall be continuously tied at joints by solid blocking not less than 16 inches (406 mm) in length and equal in size to the plate or by 1/2-inch by 11/2-inch (12.7 mm by 38 mm) metal ties with spliced sections fastened with two 16d nails on each side of the joint.
Openings in exterior and interior walls and partitions shall comply with Sections 2308.5.5.1 through 2308.5.5.3.
Headers shall be provided over each opening in exterior bearing walls. The size and spans in Table 2308.4.1.1(1) are permitted to be used for one- and two-family dwellings. Headers for other buildings shall be designed in accordance with Section 2301.2, Item 1 or 2. Headers of two or more pieces of nominal 2-inch (51 mm) framing lumber set on edge shall be permitted in accordance with Table 2308.4.1.1(1) and nailed together in accordance with Table 2304.10.1 or of solid lumber of equivalent size.
Single-member headers of nominal 2-inch (51 mm) thickness shall be framed with a single flat 2-inch-nominal (51 mm) member or wall plate not less in width than the wall studs on the top and bottom of the header in accordance with Figures 2308.5.5.1(1) and 2308.5.5.1(2) and face nailed to the top and bottom of the header with 10d box nails [3 inches × 0.128 inches (76 mm × 3.3 mm)] spaced 12 inches (305 mm) on center.
Wall studs shall support the ends of the header in accordance with Table 2308.4.1.1(1). Each end of a lintel or header shall have a bearing length of not less than 11/2 inches (38 mm) for the full width of the lintel.
FIGURE 2308.5.5.1(1)
SINGLE-MEMBER HEADER IN EXTERIOR BEARING WALL
ALTERNATIVE SINGLE-MEMBER HEADER WITHOUT CRIPPLE
Headers shall be provided over each opening in interior bearing partitions as required in Section 2308.5.5.1. The spans in Table 2308.4.1.1(2) are permitted to be used. Wall studs shall support the ends of the header in accordance with Table 2308.4.1.1(1) or 2308.4.1.1(2), as applicable.
Openings in nonbearing partitions are permitted to be framed with single studs and headers. Each end of a lintel or header shall have a bearing length of not less than 11/2 inches (38 mm) for the full width of the lintel.
Foundation cripple walls shall be framed of studs that are not less than the size of the studding above and not less than 14 inches (356 mm) in length, or shall be framed of solid blocking. Where exceeding 4 feet (1219 mm) in height, such walls shall be framed of studs having the size required for an additional story. See Section 2308.6.6 for cripple wall bracing.
Unless covered by interior or exterior wall coverings or sheathing meeting the minimum requirements of this code, stud partitions or walls with studs having a height-to-least-thickness ratio exceeding 50 shall have bridging that is not less than 2 inches (51 mm) in thickness and of the same width as the studs fitted snugly and nailed thereto to provide adequate lateral support. Bridging shall be placed in every stud cavity and at a frequency such that studs so braced shall not have a height-to-least-thickness ratio exceeding 50 with the height of the stud measured between horizontal framing and bridging or between bridging, whichever is greater.
Stud partitions containing plumbing, heating or other pipes shall be framed and the joists underneath spaced to provide proper clearance for the piping. Where a partition containing piping runs parallel to the floor joists, the joists underneath such partitions shall be doubled and spaced to permit the passage of pipes and shall be bridged. Where plumbing, heating or other pipes are placed in, or partly in, a partition, necessitating the cutting of the soles or plates, a metal tie not less than 0.058 inch (1.47 mm) (16 galvanized gage) and 11/2 inches (38 mm) in width shall be fastened to each plate across and to each side of the opening with not less than six 16d nails.
In exterior walls and bearing partitions, wood studs are permitted to be cut or notched to a depth not exceeding 25 percent of the width of the stud. Cutting or notching of studs to a depth not greater than 40 percent of the width of the stud is permitted in nonbearing partitions not supporting loads other than the weight of the partition.
Bored holes not greater than 40 percent of the stud width are permitted to be bored in any wood stud. Bored holes not greater than 60 percent of the stud width are permitted in nonbearing partitions or in any wall where each bored stud is doubled, provided that not more than two such successive doubled studs are so bored. The edge of a bored hole shall not be nearer than 5/8 inch (15.9 mm) to the edge of the stud. Bored holes shall not be located at the same section of stud as a cut or notch.
Except where stucco construction that complies with Section 2510 is installed, the outside of exterior walls, including gables, of enclosed buildings shall be sheathed with one of the materials of the nominal thickness specified in Table 2308.5.11 with fasteners in accordance with the requirements of Section 2304.10 or fasteners designed in accordance with accepted engineering practice. Alternatively, sheathing materials and fasteners complying with Section 2304.6 shall be permitted.
MINIMUM THICKNESS OF WALL SHEATHING
| SHEATHING TYPE | MINIMUM THICKNESS | MAXIMUM WALL STUD SPACING |
| Diagonal wood boards | 5/8 inch | 24 inches on center |
| Structural fiberboard | 1/2 inch | 16 inches on center |
| Wood structural panel | In accordance with Tables 2308.6.3(2) and 2308.6.3(3) | — |
| M-S "Exterior Glue" and M-2 "Exterior Glue" | In accordance with Section 2306.3 and Table 2308.6.3(4) | — |
| Gypsum sheathing | 1/2 inch | 16 inches on center |
| Reinforced cement mortar | 1 inch | 24 inches on center |
| Hardboard panel siding | In accordance with Table 2308.6.3(5) | — |
For SI: 1 inch = 25.4 mm.
Buildings shall be provided with exterior and interior braced wall lines as described in Sections 2308.6.1 through 2308.6.10.2.
For the purpose of determining the amount and location of bracing required along each story level of a building, braced wall lines shall be designated as straight lines through the building plan in both the longitudinal and traverse direction and placed in accordance with LAMC Table 2308.6.1 and CBC Figure 2308.6.1. Braced wall line spacing shall not exceed the distance specified in LAMC Table 2308.6.1. In structures assigned to Seismic Design Category D or E, braced wall lines shall intersect perpendicularly to each other.
Wall framing to which sheathing used for bracing is applied shall be nominal 2 inch wide [actual 1-1/2 inch (38 mm)] or larger members. Braced wall panel construction types shall not be mixed within a braced wall line. Braced wall panels required by LAMC Section 91.2308.6.1 may be eliminated when all of the following requirements are met:
Wall framing to which sheathing used for bracing is applied shall be nominal 2 inch wide [actual 1-1/2 inch (38 mm)] or larger members. Braced wall panel construction types shall not be mixed within a braced wall line. Braced wall panels required by LAMC Section 91.2308.6.1 may be eliminated when all of the following requirements are met:
- One story detached Group U occupancies are not more than 25 feet (7.62 m) in depth or length.
- The roof and three enclosing walls are solid sheathed with 1/2 inch (12.7 mm) nominal thickness wood structural panels with 8d common nails placed 3/8 inches (9.525 mm) from panel edges and spaced not more than 6 inches (152.4 mm) on center along all panel edges and 12 inches (304.8 mm) on center along intermediate framing members. Wall openings for doors or windows are permitted provided a minimum 4 foot (1219.2 mm) wide wood structural braced panel with a minimum height to length ratio of 2 to 1 is provided at each end of the wall line and that the wall line be sheathed for 50% of its length.
| SEISMIC DESIGN CATEGORY |
STORY CONDITION (SEE SECTION 2308.2) |
MAXIMUM SPACING OF BRACED WALL LINES |
BRACED PANEL LOCATION, SPACING (O.C.) AND MINIMUM PERCENTAGE (X) |
MAXIMUM DISTANCE OF BRACED WALL PANELS FROM EACH END OF BRACED WALL LINE |
||
| Bracing methodb | ||||||
| LIB | DWB, WSP | SFB, PBS, PCP, HPS, Gbc, d | ||||
| A and B | 35' - 0" | Each end and ≤ 25'- 0" o.c. |
Each end and ≤ 25'- 0" o.c. |
Each end and ≤ 25'- 0" o.c. |
12'- 6" | |
| 35'- 0" | Each end and ≤ 25'- 0" o.c. |
Each end and ≤ 25'- 0" o.c. |
Each end and ≤ 25'- 0" o.c. |
12'- 6" | ||
| 35'- 0" | NP | Each end and ≤ 25'- 0" o.c. |
Each end and ≤ 25'- 0" o.c. |
12'- 6" | ||
| C | 35'- 0" | NP | Each end and ≤ 25'- 0" o.c. |
Each end and ≤ 25'- 0" o.c. |
12'- 6" | |
| 35'- 0" | NP | Each end and ≤ 25'- 0" o.c. (minimum 25% of wall length)e |
Each end and ≤ 25'- 0" o.c. (minimum 25% of wall length)e |
12'- 6" | ||
| D and E | 25'- 0" | NP | SDS < 0.50: Each end and 25'- 0" o.c. (minimum 21% of wall length)e, f, g, h |
SDS < 0.50: Each end and 25'- 0" o.c. (minimum 43% of wall length)e, f, g, h |
8'- 0" | |
| 0.5 ≤SDS < 0.75: Each end and 25'- 0" o.c. (minimum 32% of wall length)e, f, g, h |
0.5 ≤SDS< 0.75: Each end and 25'- 0" o.c. (minimum 59% of wall length)e, f, g, h |
|||||
| 0.75 ≤SDS ≤ 1.00: Each end and 25'- 0" o.c. (minimum 37% of wall length)e, f, g, h |
0.75 ≤SDS ≤ 1.00: Each end and 25'- 0" o.c. (minimum 75% of wall length)e, f, g, h |
|||||
| SDS > 1.00: Each end and 25'- 0" o.c. (minimum 48% of wall length)e, f, g, h |
SDS > 1.00: Each end and 25'- 0" o.c. (minimum 100% of wall length)e, f, g, h |
|||||
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
NP = Not Permitted.
NP = Not Permitted.
- This table specifies minimum requirements for braced wall panels along interior or exterior braced wall lines.
- See Section 2308.6.3 for full description of bracing methods.
- For Method GB, gypsum wallboard applied to framing supports that are spaced at 16 inches on center.
- The required lengths shall be doubled for gypsum board applied to only one face of a braced wall panel.
- Percentage shown represents the minimum amount of bracing required along the building length (or wall length if the structure has an irregular shape).
- Minimum length of panel bracing of one face of the wall for WSP sheathing shall be at least 4'-0" long or both feces of the wall for GB sheathing shall be at least 8'-0" long; h/w ratio shall not exceed 2:1. For WSP panel bracing of the same material on two faces of the wall, the minimum length is permitted to be one-half of the tabulated value, but the h/w ratio shall not exceed 2:1 and design for uplift is required. The 2:1 h/w ratio limitation does not apply to alternate braced wall panels constructed in accordance with Section 2308.6.5.1 or 2308.6.5.2.
- Nailing as specified below shall occur at all panel edges at studs, at top and bottom plates and, where occurring, at blocking:
For 1/2-inch gypsum board, 5d (0.113-inch diameter) cooler nails at 7 inches on center;
For 5/8-inch gypsum board, No. 11 gage (0.120-inch diameter) at 7 inches on center;
For gypsum sheathing board, 1-3/4 inches long by 7/l6-inch head, diamond point galvanized nails at 4 inches on center;
For gypsum lath, No. 13 gage (0.092 inch) by 1-1/8 inches long, 19/64-inch head, plasterboard at 5 inches on center; and
For Portland cement plaster, No. 11 gage (0.120 inch) by 1-1/2 inches long, 7/l6-inch head at 6 inches on center. - WSP sheathing shall be a minimum of 15/32" thick nailed with 8d common placed 3/8 inch from panel edges and spaced not more than 6 inches on center and 12 inches on center along intermediate framing members.
Braced wall panels shall be placed along braced wall lines in accordance with Table 2308.6.1 and Figure 2308.6.1 and as specified in Table 2308.6.3(1). A braced wall panel shall be located at each end of the braced wall line and at the corners of intersecting braced wall lines or shall begin within the maximum distance from the end of the braced wall line in accordance with Table 2308.6.1. Braced wall panels in a braced wall line shall not be offset from each other by more than 4 feet (1219 mm). Braced wall panels shall be clearly indicated on the plans.
Construction of braced wall panels shall be by one or a combination of the methods in Table 2308.6.3(1). Braced wall panel length shall be in accordance with Section 2308.6.4 or 2308.6.5.
BRACING METHODS
| METHODS, MATERIAL | MINIMUM THICKNESS | FIGURE | CONNECTION CRITERIAa | |
| Fasteners | Spacing | |||
| LIBa Let-in-bracing | 1" × 4" wood or approved metal straps attached at 45° to 60° angles to studs at maximum of 16" o.c. | Table 2304.10.1 | Wood: per stud plus top and bottom plates | |
| Metal strap: installed in accordance with manufacturer's recommendations | Metal strap: installed in accordance with manufacturer's recommendations | |||
| DWB Diagonal wood | 3/4" thick (1" nominal) × 6" minimum width to studs at maximum of 24" o.c. | Table 2304.10.1 | Per stud | |
| WSP Wood structural | 3/8" in accordance with Table 2308.6.3(2) or 2308.6.3(3) |
| Table 2304.10.1 | 6" edges 12" field |
| SFB Structural fiberboard sheathing | 1/2" in accordance with Table 2304.10.1 to studs at maximum 16" o.c. |
| Table 2304.10.1 | 3" edges 6" field |
| GB (Double sided) | 1/2" or 5/8" by not less than 4' wide to studs at maximum of 24" o.c. | Section 2506.2 for exterior and interior sheathing: 5d annual ringed cooler nails (15/8" × 0.086") or 11/4" screws (Type W or S) for 1/2" gypsum board or 15/8" screws (Type W or S) for 5/8" gypsum board | For all braced wall panel locations: 7" o.c. along panel edges (including top and bottom plates) and 7" o.c. in the field | |
| PBS Particleboard sheathing | 3/8" or 1/2" in accordance with Table 2308.6.3(4) to studs at maximum of 16" o.c. |
| 6d common (2" long × 0.113" dia.) nails for 3/8" thick sheathing or 8d common (21/2" long × 0.131" dia.) nails for 1/2" thick sheathing | 3" edges 6" field |
| PCP Portland cement plaster | Section 2510 to studs at maximum of 16" o.c. |
| 11/2" long, 11 gage, 7/16" dia. head nails or 7/8" long, 16 gage staples | 6" o.c. on all framing members |
| HPS | 7/16" in accordance with Table 2308.6.3(5) |
| Table 2304.10.1 | 4" edges 8" field |
| ABW Alternate braced wall | 3/8" | Figure 2308.6.5.1 and | Figure 2308.6.5.1 | |
| PFH Portal frame with hold- downs | 3/8" | Figure 2308.6.5.2 and | Figure 2308.6.5.2 | |
For SI: 1 foot = 304.8 mm, 1 degree = 0.01745 rad.
- Method LIB shall have gypsum board fastened to one or more side(s) with nails or screws
| MINIMUM THICKNESSa (inch) | MINIMUM NUMBER OF PLIES | STUD SPACING (inches) Plywood siding applied directly to studs or over sheathing |
| 3/8 | 3 | 16b |
| 1/2 | 4 | 24 |
For SI: 1 inch = 25.4 mm.
- Thickness of grooved panels is measured at bottom of grooves.
- Spans are permitted to be 24 inches if plywood siding applied with face grain perpendicular to studs or over one of the following: 1-inch board sheathing; 7/16 - inch wood structural panel sheathing; or 3/8-inch wood structural panel sheathing with strength axis (which is the long direction of the panel unless otherwise marked) of sheathing perpendicular to studs.
WOOD STRUCTURAL PANEL WALL SHEATHINGb (Not exposed to the weather, strength axis parallel or perpendicular to studs except as Indicated)
| MINIMUM THICKNESS (inch) | PANEL SPAN RATING | STUD SPACING (inches) | ||
| Siding nailed to studs | Nailable sheathing | |||
| Sheathing parallel to studs | Sheathing perpendicular to studs | |||
| 3/8,15/32,1/2 | 16/0, 20/0, 24/0, 32/16 Wall—24" o.c. | 24 | 16 | 24 |
| 7/16,15/32,1/2 | 24/0, 24/16, 32/16 Wall—24" o.c. | 24 | 24a | 24 |
For SI: 1 inch = 25.4 mm.
- Plywood shall consist of four or more plies.
- Blocking of horizontal joints shall not be required except as specified in Section 2308.6.4.
ALLOWABLE SPANS FOR PARTICLEBOARD WALL SHEATHING (Not exposed to the weather, long dimension of the panel parallel or perpendicular to studs)
| GRADE | THICKNESS (inch) | STUD SPACING (inches) | |
| Siding nailed to studs | Sheathing under coverings specified in Section 2308.6.3 parallel or perpendicular to studs | ||
| M-S "Exterior Glue" and M-2 "Exterior Glue" | 3/8 | 16 | — |
| 1/2 | 16 | 16 | |
For SI: 1 inch = 25.4 mm.
HARDBOARD SIDING
| SIDING | MINIMUM NOMINAL THICKNESS (inch) | 2 × 4 FRAMING MAXIMUM SPACING | NAIL SIZEa, b, d | NAIL SPACING | |
| General | Bracing panelsc | ||||
| 1. Lap siding | |||||
| Direct to studs | 3/8 | 16" o.c. | 8d | 16" o.c. | Not applicable |
| Over sheathing | 3/8 | 16" o.c. | 10d | 16" o.c. | Not applicable |
| 2. Square edge panel siding | |||||
| Direct to studs | 3/8 | 24" o.c. | 6d | 6" o.c. edges; 12" o.c. at intermediate supports | 4" o.c. edges; 8" o.c. at intermediate supports |
| Over sheathing | 3/8 | 24" o.c. | 8d | 6" o.c. edges; 12" o.c. at intermediate supports | 4" o.c. edges; 8" o.c. at intermediate supports |
| 3. Shiplap edge panel siding | |||||
| Direct to studs | 3/8 | 16" o.c. | 6d | 6" o.c. edges; 12" o.c. at intermediate supports | 4" o.c. edges; 8" o.c. at intermediate supports |
| Over sheathing | 3/8 | 16" o.c. | 8d | 6" o.c. edges; 12" o.c. at intermediate supports | 4" o.c. edges; 8" o.c. at intermediate supports |
For SI: 1 inch = 25.4 mm.
- Nails shall be corrosion resistant.
- Minimum acceptable nail dimensions:
Where used to comply with Section 2308.6.
Panel Siding (inch) Lap Siding (inch) Shank diameter 0.092 0.099 Head diameter 0.225 0.240 - Nail length must accommodate the sheathing and penetrate framing 11/2 inches.
For Methods DWB, WSP, SFB, PBS, PCP and HPS, each panel must be not less than 48 inches (1219 mm) in length, covering three stud spaces where studs are spaced 16 inches (406 mm) on center and covering two stud spaces where studs are spaced 24 inches (610 mm) on center. Braced wall panels less than 48 inches (1219 mm) in length shall not contribute toward the amount of required bracing. Braced wall panels that are longer than the required length shall be credited for their actual length. For Method GB, each panel must be not less than 96 inches (2438 mm) in length where applied to one side of the studs or 48 inches (1219 mm) in length where applied to both sides.
Vertical joints of panel sheathing shall occur over studs and adjacent panel joints shall be nailed to common framing members. Horizontal joints shall occur over blocking or other framing equal in size to the studding except where waived by the installation requirements for the specific sheathing materials. Sole plates shall be nailed to the floor framing in accordance with Section 2308.6.7 and top plates shall be connected to the framing above in accordance with Section 2308.6.7.2. Where joists are perpendicular to braced wall lines above, blocking shall be provided under and in line with the braced wall panels.
An alternate braced wall (ABW) or a portal frame with hold-downs (PFH) described in this section is permitted to substitute for a 48-inch (1219 mm) braced wall panel of Method DWB, WSP, SFB, PBS, PCP or HPS. For Method GB, each 96-inch (2438 mm) section (applied to one face) or 48-inch (1219 mm) section (applied to both faces) or portion thereof required by Table 2308.6.1 is permitted to be replaced by one panel constructed in accordance with Method ABW or PFH.
An ABW shall be constructed in accordance with this section and CBC Figure 2308.6.5.1. In one-story buildings, each panel shall have a length of not less than 2 feet 8 inches (813 mm) and a height of not more than 10 feet (3048 mm). Each panel shall be sheathed on one face with 15/32 inch (11.9 mm) minimum-thickness wood structural panel sheathing nailed with 8d common or galvanized box nails in accordance with LAMC Table 2304.10.1 and blocked at wood structural panel edges. Two anchor bolts installed in accordance with CBC Section 2308.3.1 shall be provided in each panel. Anchor bolts shall be placed at each panel outside quarter points. Each panel end stud shall have a hold-down device fastened to the foundation, capable of providing an approved uplift capacity of not less than 1,800 pounds (8006 N). The hold-down device shall be installed in accordance with the manufacturer's recommendations. The ABW shall be supported directly on a foundation, or on floor framing supported directly on a foundation that is continuous across the entire length of the braced wall line. This foundation shall be reinforced with not less than one No. 4 bar top and bottom. Where the continuous foundation is required to have a depth greater than 12 inches (305 mm), a minimum 12 inch by 12 inch (305 mm by 305 mm) continuous footing or turned-down slab edge is permitted at door openings in the braced wall line. This continuous footing or turned-down slab edge shall be reinforced with not less than one No. 4 bar top and bottom. This reinforcement shall be lapped 15 inches (381 mm) with the reinforcement required in the continuous foundation located directly under the braced wall line.
Where the ABW is installed at the first story of a two-story building, the wood structural panel sheathing shall be provided on both faces, three anchor bolts shall be placed at one-quarter points, and tie-down device uplift capacity shall be not less than 3,000 pounds (13 344 N).
Where the ABW is installed at the first story of a two-story building, the wood structural panel sheathing shall be provided on both faces, three anchor bolts shall be placed at one-quarter points, and tie-down device uplift capacity shall be not less than 3,000 pounds (13 344 N).
A PFH shall be constructed in accordance with this section and CBC Figure 2308.6.5.2. The adjacent door or window opening shall have a full-length header.
In one-story buildings, each panel shall have a length of not less than 16 inches (406 mm) and a height of not more than 10 feet (3048 mm). Each panel shall be sheathed on one face with a single layer of 15/32 inch (11.9 mm) minimum-thickness wood structural panel sheathing nailed with 8d common or galvanized box nails in accordance with CBC Figure 2308.6.5.2. The wood structural pane sheathing shall extend up over the solid sawn or glued-laminated header and shall be nailed in accordance with CBC Figure 2308.6.5.2. A built-up header consisting of at least two 2 inch by 12 inch (51 mm by 305 mm) boards, fastened in accordance with Item 24 of LAMC Table 2304.10.1 shall be permitted to be used. A spacer, if used, shall be placed on the side of the built-up beam opposite the wood structural panel sheathing. The header shall extend between the inside faces of the first full-length outer studs of each panel. The clear span of the header between the inner studs of each panel shall be not less than 6 feet (1829 mm) and not more than 18 feet (5486 mm) in length. A strap with an uplift capacity of not less than 1,000 pounds (4400 N) shall fasten the header to the inner studs opposite the sheathing. One anchor bolt not less than 5/8 inch (15.9 mm) in diameter and installed in accordance with CBC Section 2308.3.1 shall be provided in the center of each sill plate. The studs at each end of the panel shall have a hold-down device fastened to the foundation with an uplift capacity of not less than 3,500 pounds (15 570 N).
Where a panel is located on one side of the opening, the header shall extend between the inside face of the first full-length stud of the panel and the bearing studs at the other end of the opening. A strap with an uplift capacity of not less than 1,000 pounds (4400 N) shall fasten the header to the bearing studs. The bearing studs shall also have a hold-down device fastened to the foundation with an uplift capacity of not less than 1,000 pounds (4400 N). The hold-down devices shall be an embedded strap type, installed in accordance with the manufacturer's recommendations. The PFH panels shall be supported directly on a foundation that is continuous across the entire length of the braced wall line. This foundation shall be reinforced with not less than one No. 4 bar top and bottom. Where the continuous foundation is required to have a depth greater than 12 inches (305 mm), a minimum 12 inch by 12 inch (305 mm by 305 mm) continuous footing or turned-down slab edge is permitted at door openings in the braced wall line. This continuous footing or turned-down slab edge shall be reinforced with not less than one No. 4 bar top and bottom. This reinforcement shall be lapped not less than 15 inches (381 mm) with the reinforcement required in the continuous foundation located directly under the braced wall line.
Where a PFH is installed at the first story of a two-story building, each panel shall have a length of not less than 24 inches (610 mm).
In one-story buildings, each panel shall have a length of not less than 16 inches (406 mm) and a height of not more than 10 feet (3048 mm). Each panel shall be sheathed on one face with a single layer of 15/32 inch (11.9 mm) minimum-thickness wood structural panel sheathing nailed with 8d common or galvanized box nails in accordance with CBC Figure 2308.6.5.2. The wood structural pane sheathing shall extend up over the solid sawn or glued-laminated header and shall be nailed in accordance with CBC Figure 2308.6.5.2. A built-up header consisting of at least two 2 inch by 12 inch (51 mm by 305 mm) boards, fastened in accordance with Item 24 of LAMC Table 2304.10.1 shall be permitted to be used. A spacer, if used, shall be placed on the side of the built-up beam opposite the wood structural panel sheathing. The header shall extend between the inside faces of the first full-length outer studs of each panel. The clear span of the header between the inner studs of each panel shall be not less than 6 feet (1829 mm) and not more than 18 feet (5486 mm) in length. A strap with an uplift capacity of not less than 1,000 pounds (4400 N) shall fasten the header to the inner studs opposite the sheathing. One anchor bolt not less than 5/8 inch (15.9 mm) in diameter and installed in accordance with CBC Section 2308.3.1 shall be provided in the center of each sill plate. The studs at each end of the panel shall have a hold-down device fastened to the foundation with an uplift capacity of not less than 3,500 pounds (15 570 N).
Where a panel is located on one side of the opening, the header shall extend between the inside face of the first full-length stud of the panel and the bearing studs at the other end of the opening. A strap with an uplift capacity of not less than 1,000 pounds (4400 N) shall fasten the header to the bearing studs. The bearing studs shall also have a hold-down device fastened to the foundation with an uplift capacity of not less than 1,000 pounds (4400 N). The hold-down devices shall be an embedded strap type, installed in accordance with the manufacturer's recommendations. The PFH panels shall be supported directly on a foundation that is continuous across the entire length of the braced wall line. This foundation shall be reinforced with not less than one No. 4 bar top and bottom. Where the continuous foundation is required to have a depth greater than 12 inches (305 mm), a minimum 12 inch by 12 inch (305 mm by 305 mm) continuous footing or turned-down slab edge is permitted at door openings in the braced wall line. This continuous footing or turned-down slab edge shall be reinforced with not less than one No. 4 bar top and bottom. This reinforcement shall be lapped not less than 15 inches (381 mm) with the reinforcement required in the continuous foundation located directly under the braced wall line.
Where a PFH is installed at the first story of a two-story building, each panel shall have a length of not less than 24 inches (610 mm).
For the purposes of this section, cripple walls in Seismic Design Categories A, B and C having a stud height exceeding 14 inches (356 mm) shall be considered to be a story and shall be braced in accordance with Table 2308.6.1. Spacing of edge nailing for required cripple wall bracing shall not exceed 6 inches (152 mm) on center along the foundation plate and the top plate of the cripple wall. Nail size, nail spacing for field nailing and more restrictive boundary nailing requirements shall be as required elsewhere in the code for the specific bracing material used.
For the purposes of this section, cripple walls in Seismic Design Categories D and E having a stud height exceeding 14 inches (356 mm) shall be considered to be a story and shall be braced in accordance with Table 2308.6.1. Where interior braced wall lines occur without a continuous foundation below, the length of parallel exterior cripple wall bracing shall be one and one-half times the lengths required by Table 2308.6.1. Where the cripple wall sheathing type used is Method WSP or DWB and this additional length of bracing cannot be provided, the capacity of WSP or DWB sheathing shall be increased by reducing the spacing of fasteners along the perimeter of each piece of sheathing to 4 inches (102 mm) on center.
Braced wall panel joints shall occur over studs or blocking. Braced wall panels shall be fastened to studs, top and bottom plates and at panel edges. Braced wall panels shall be applied to nominal 2-inch-wide [actual 11/2-inch (38 mm)] or larger stud framing.
Braced wall line bottom plates shall be connected to joists or full-depth blocking below in accordance with Table 2304.10.1, or to foundations in accordance with Section 2308.6.7.3.
Where joists or rafters are used, braced wall line top plates shall be fastened over the full length of the braced wall line to joists, rafters, rim boards or full-depth blocking above in accordance with Table 2304.10.1, as applicable, based on the orientation of the joists or rafters to the braced wall line. Blocking shall be not less than 2 inches (51 mm) in nominal thickness and shall be fastened to the braced wall line top plate as specified in Table 2304.10.1. Notching or drilling of holes in blocking in accordance with the requirements of Section 2308.4.2.4 or 2308.7.4 shall be permitted.
At exterior gable end walls, braced wall panel sheathing in the top story shall be extended and fastened to the roof framing where the spacing between parallel exterior braced wall lines is greater than 50 feet (15 240 mm).
Where roof trusses are used and are installed perpendicular to an exterior braced wall line, lateral forces shall be transferred from the roof diaphragm to the braced wall over the full length of the braced wall line by blocking of the ends of the trusses or by other approved methods providing equivalent lateral force transfer. Blocking shall be not less than 2 inches (51 mm) in nominal thickness and equal to the depth of the truss at the wall line and shall be fastened to the braced wall line top plate as specified in Table 2304.10.1. Notching or drilling of holes in blocking in accordance with the requirements of Section 2308.4.2.4 or 2308.7.4 shall be permitted.
Exception: Where the roof sheathing is greater than 91/4 inches (235 mm) above the top plate, solid blocking is not required where the framing members are connected using one of the following methods:
- In accordance with Figure 2308.6.7.2(1).
- In accordance with Figure 2308.6.7.2(2).
- Full-height engineered blocking panels designed for values listed in AWC WFCM.
- A design in accordance with accepted engineering methods.
a. Methods of bracing shall be as described in Table 2308.6.3(1) DWB, WSP, SFB, GB, PBS, PCP or HPS.
For SI: 1 foot = 304.8 mm.
BRACED WALL LINE TOP PLATE CONNECTION
a. Methods of bracing shall be as described in Table 2308.6.3(1) DWB, WSP, SFB, GB, PBS, PCP or HP
For SI: 1 foot = 304.8 mm.
BRACED WALL PANEL TOP PLATE CONNECTION
Where foundations are required by Section 2308.6.8, braced wall line sills shall be anchored to concrete or masonry foundations. Such anchorage shall conform to the requirements of Section 2308.3. The anchors shall be distributed along the length of the braced wall line. Other anchorage devices having equivalent capacity are permitted.
Where all-wood foundations are used, the force transfer from the braced wall lines shall be determined based on calculation and shall have a capacity that is not less than the connections required by Section 2308.3.
Braced wall lines and floor and roof diaphragms shall be supported in accordance with this section.
Braced wall lines shall be supported by continuous foundations.
For structures in Seismic Design Categories D and E, exterior braced wall panels shall be in the same plane vertically with the foundation or the portion of the structure containing the offset shall be designed in accordance with accepted engineering practice and CBC Section 2308.1.1.
Exception:
For structures with a maximum plan dimension not over 50 feet (15.24 m), continuous foundations are required at exterior walls only for structures not assigned to Seismic Design Category D, E or F.
For structures in Seismic Design Categories D and E, exterior braced wall panels shall be in the same plane vertically with the foundation or the portion of the structure containing the offset shall be designed in accordance with accepted engineering practice and CBC Section 2308.1.1.
Exceptions:
-
Exterior braced wall panels shall be permitted to be located not more than 4 feet (1219 mm) from the foundation below where supported by a floor constructed in accordance with all of the following:
- Cantilevers or setbacks shall not exceed four times the nominal depth of the floor joists.
- Floor joists shall be 2 inches by 10 inches (51 mm by 254 mm) or larger, and spaced not more than 16 inches (406 mm) on center.
- The ratio of the back span to the cantilever shall be not less than 2 to 1.
- Floor joists at ends of braced wall panels shall be doubled.
- A continuous rim joist shall be connected to the ends of cantilevered joists. The rim joist is permitted to be spliced using a metal tie not less than 0.058 inch (1.47 mm) (16 galvanized gage) and 1-1/2 inches (38 mm) in width fastened with six 16d common nails on each side. The metal tie shall have a yield stress not less than 33,000 psi (227 MPa).
- Joists at setbacks or the end of cantilevered joists shall not carry gravity loads from more than a single story having uniform wall and roof loads nor carry the reactions from headers having a span of 8 feet (2438 mm) or more.
- The end of a required braced wall panel shall be allowed to extend not more than 1 foot (305 mm) over an opening in the wall below. This requirement is applicable to braced wall panels offset in plane and braced wall panels offset out of plane, as permitted by Exception 1. Braced wall panels are permitted to extend over an opening not more than 8 feet (2438 mm) in width where the header is a 4 inch by 12 inch (102 mm by 305 mm) or larger member.
In structures assigned to Seismic Design Categories D or E, floor and roof diaphragms shall be laterally supported by braced wall lines on all edges and connected in accordance with Section 2308.6.7 [see Figure 2308.6.8.2(1)].
Exception: Portions of roofs or floors that do not support braced wall panels above are permitted to extend up to 6 feet (1829 mm) beyond a braced wall line [see Figure 2308.6.8.2(2)] provided that the framing members are connected to the braced wall line below in accordance with Section 2308.6.7.
ROOF IN SDC D OR E NOT SUPPORTED ON ALL EDGES
For SI: 1 foot = 304.8 mm.
ROOF EXTENSION IN SDC D OR E BEYOND BRACED WALL LINE
In Seismic Design Categories B, C, D and E, where the height of a required braced wall panel extending from foundation to floor above varies more than 4 feet (1219 mm), the following construction shall be used:
- Where the bottom of the footing is stepped and the lowest floor framing rests directly on a sill bolted to the footings, the sill shall be anchored as required in Section 2308.3.
- Where the lowest floor framing rests directly on a sill bolted to a footing not less than 8 feet (2438 mm) in length along a line of bracing, the line shall be considered to be braced. The double plate of the cripple stud wall beyond the segment of footing extending to the lowest framed floor shall be spliced to the sill plate with metal ties, one on each side of the sill and plate. The metal ties shall be not less than 0.058 inch [1.47 mm (16 galvanized gage)] by 11/2 inches (38 mm) in width by 48 inches (1219 mm) with eight 16d common nails on each side of the splice location (see Figure 2308.6.8.3). The metal tie shall have a yield stress not less than 33,000 pounds per square inch (psi) (227 MPa).
- Where cripple walls occur between the top of the footing and the lowest floor framing, the bracing requirements for a story shall apply.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
STEPPED FOOTING CONNECTION DETAILS
Fastening of braced wall panel sheathing shall not be less than that prescribed in LAMC Table 2308.6.1 and CBC Table 2304.10.1. Wall sheathing shall not be attached to framing members by adhesives. Staple fasteners in CBC Table 2304.10.1 shall not be used to resist or transfer seismic forces in structures assigned to Seismic Design Category D, E or F.
All braced wall panels shall extend to the roof sheathing and shall be attached to parallel roof rafters or blocking above with framing clips (18 gauge minimum) spaced at maximum 24 inches (6096 mm) on center four 8d nails per leg (total 8d nails per clip). Braced wall panels shall be laterally braced at each top corner and at maximum 24 inch (6096 mm) intervals along the top plate of discontinuous vertical framing.
EXCEPTION: Staples may be used to resist or transfer seismic forces when the allowable shear values are substantiated by cyclic testing and approved by the Superintendent of Building.
All braced wall panels shall extend to the roof sheathing and shall be attached to parallel roof rafters or blocking above with framing clips (18 gauge minimum) spaced at maximum 24 inches (6096 mm) on center four 8d nails per leg (total 8d nails per clip). Braced wall panels shall be laterally braced at each top corner and at maximum 24 inch (6096 mm) intervals along the top plate of discontinuous vertical framing.
In Seismic Design Categories B and C, concrete or masonry walls and stone or masonry veneer shall not extend above a basement.
Exceptions:
- In structures assigned to Seismic Design Category B, stone and masonry veneer is permitted to be used in the first two stories above grade plane or the first three stories above grade plane where the lowest story has concrete or masonry walls, provided that wood structural panel wall bracing is used and the length of bracing provided is one and one-half times the required length specified in Table 2308.6.1.
- Stone and masonry veneer is permitted to be used in the first story above grade plane or the first two stories above grade plane where the lowest story has concrete or masonry walls.
Stone and masonry veneer is permitted to be used in both stories of buildings with two stories above grade plane, provided that the following criteria are met:
- 3.1. Type of brace in accordance with Section 2308.6.1 shall be WSP and the allowable shear capacity in accordance with Section 2306.3 shall be not less than 350 plf (5108 N/m).
- 3.2. Braced wall panels in the second story shall be located in accordance with Section 2308.6.1 and not more than 25 feet (7620 mm) on center, and the total length of braced wall panels shall be not less than 25 percent of the braced wall line length. Braced wall panels in the first story shall be located in accordance with Section 2308.6.1 and not more than 25 feet (7620 mm) on center, and the total length of braced wall panels shall be not less than 45 percent of the braced wall line length.
- 3.3. Hold-down connectors with an allowable capacity of 2,000 pounds (8896 N) shall be provided at the ends of each braced wall panel for the second story to the first story connection. Hold-down connectors with an allowable capacity of 3,900 pounds (17 347 N) shall be provided at the ends of each braced wall panel for the first story to the foundation connection. In all cases, the hold-down connector force shall be transferred to the foundation.
- 3.4. Cripple walls shall not be permitted.
In Seismic Design Categories D and E, concrete or masonry walls and stone or masonry veneer shall not extend above a basement.
Exception:
In structures assigned to Seismic Design Category D, stone and masonry veneer is permitted to be used in the first story above grade plane, provided the following criteria are met:
- The type of brace in accordance with LAMC Subdivision 91.2308.6.1 shall be WSP, and the allowable shear capacity in accordance with LAMC Section 91.2306.3 shall be not less than 350 plf (5108 N/m).
- The braced wall panels in the first story shall be located at each end of the braced wall line and not more than 25 feet (7620 mm) on center, and the total length of braced wall panels shall be not less than 45% of the braced wall line length.
- Hold-down connectors shall be provided at the ends of braced walls for the first floor to foundation with an allowable capacity of 2,100 pounds (9341 N).
- Cripple walls shall not be permitted.
- Anchored masonry and stone wall veneer not exceeding 5 inches (127 mm) in thickness shall conform to the requirements of Division 14, Article 1, Chapter IX of the Los Angeles Municipal Code and shall not extend more than 5 feet (1524 mm) above the first-story finished floor.
The framing details required in this section apply to roofs having a slope of not less than three units vertical in 12 units horizontal (25-percent slope). Where the roof slope is less than three units vertical in 12 units horizontal (25-percent slope), members supporting rafters and ceiling joists such as ridge board, hips and valleys shall be designed as beams.
Spans for ceiling joists shall be in accordance with Table 2308.7.1(1) or 2308.7.1(2). For other grades and species, and other loading conditions, refer to the AWC STJR.
CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable attics without storage, live load = 10 psf, L/Δ = 240)
| CEILING JOIST SPACING (inches) | SPECIES AND GRADE | DEAD LOAD = 5 psf | ||||
| 2 × 4 | 2 × 6 | 2 × 8 | 2 × 10 | |||
| Maximum ceiling joist spans | ||||||
| (ft. - in.) | (ft. - in.) | (ft. - in.) | (ft. - in.) | |||
| 12 | Douglas Fir-Larch | SS | 13-2 | 20-8 | Note a | Note a |
| Douglas Fir-Larch | #1 | 12-8 | 19-11 | Note a | Note a | |
| Douglas Fir-Larch | #2 | 12-5 | 19-6 | 25-8 | Note a | |
| Douglas Fir-Larch | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| Hem-Fir | SS | 12-5 | 19-6 | 25-8 | Note a | |
| Hem-Fir | #1 | 12-2 | 19-1 | 25-2 | Note a | |
| Hem-Fir | #2 | 11-7 | 18-2 | 24-0 | Note a | |
| Hem-Fir | #3 | 10-10 | 15-10 | 20-1 | 24-6 | |
| Southern Pine | SS | 12-11 | 20-3 | Note a | Note a | |
| Southern Pine | #1 | 12-5 | 19-6 | 25-8 | Note a | |
| Southern Pine | #2 | 11-10 | 18-8 | 24-7 | Note a | |
| Southern Pine | ||||||