CODES

ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Copyright

Preface

Chapter 1 Scope and Administration

Chapter 2 Definitions

Chapter 3 Building Planning

Chapter 4 Foundations

Chapter 5 Floors

Chapter 6 Wall Construction

Chapter 7 Wall Covering

Chapter 8 Roof-Ceiling Construction

Chapter 9 Roof Assemblies

Chapter 10 Chimneys and Fireplaces

Chapter 11 [Re] Energy Efficiency

Chapter 12 Mechanical Administration

Chapter 13 General Mechanical System Requirements

Chapter 14 Heating and Cooling Equipment and Appliances

Chapter 15 Exhaust Systems

Chapter 16 Duct Systems

Chapter 17 Combustion Air

Chapter 18 Chimneys and Vents

Chapter 19 Special Appliances, Equipment and Systems

Chapter 20 Boilers and Water Heaters

Chapter 21 Hydronic Piping

Chapter 22 Special Piping and Storage Systems

Chapter 23 Solar Thermal Energy Systems

Chapter 24 Fuel Gas

Chapter 25 Plumbing Administration

Chapter 26 General Plumbing Requirements

Chapter 27 Plumbing Fixtures

Chapter 28 Water Heaters

Chapter 29 Water Supply and Distribution

Chapter 30 Sanitary Drainage

Chapter 31 Vents

Chapter 32 Traps

Chapter 33 Storm Drainage

Chapter 34 General Requirements

Chapter 35 Electrical Definitions

Chapter 36 Services

Chapter 37 Branch Circuit and Feeder Requirements

Chapter 38 Wiring Methods

Chapter 39 Power and Lighting Distribution

Chapter 40 Devices and Luminaires

Chapter 41 Appliance Installation

Chapter 42 Swimming Pools [Electrical Provisions]

Chapter 43 Class 2 Remote-Control, Signaling and Power-Limited Circuits

Chapter 44 High-Velocity Hurricane Zones

Chapter 45 Private Swimming Pools

Chapter 46 Referenced Standards

Appendix A Sizing and Capacities of Gas Piping

Appendix B Sizing of Venting Systems Serving Appliances Equipped With Draft Hoods, Category I Appliances, and Appliances Listed for Use With Type B Vents

Appendix C Exit Terminals of Mechanical Draft and Direct-Vent Venting Systems

Appendix D Recommended Procedure for Safety Inspection of an Existing Appliance Installation

Appendix E Florida Standard for Mitigation of Radon in Existing Buildings Effective: June 1, 1994

Appendix F Florida Standard for Passive Radon-Resistant New Residential Building Construction

Appendix G Piping Standards for Various Applications

Appendix H Patio Covers

Appendix I Private Sewage Disposal

Appendix J Existing Buildings and Structures

Appendix K Sound Transmission

Appendix L Permit Fees

Appendix M Home Day Care—r-3 Occupancy

Appendix N Venting Methods

Appendix O Automatic Vehicular Gates

Appendix P Sizing of Water Piping System

Appendix Q Reserved

Appendix R Light Straw-Clay Construction

Appendix S Strawbale Construction

Appendix T Recommended Procedure for Worst-Case Testing of Atmospheric Venting Systems Under N1102.4 or N1105 Conditions ≤ 5ach 50

Appendix U Solar-Ready Provisions—detached One- And Two-Family Dwellings, Multiple Single- Family Dwellings (Townhouses)

The provisions of this chapter shall control the design and construction of the roof-ceiling system for buildings.

Exception: Buildings and structures located within the High-Velocity Hurricane Zone shall comply with the provisions of Chapter 44.

Roof and ceiling construction shall be capable of accommodating all loads imposed in accordance with Section R301 and of transmitting the resulting loads to the supporting structural elements.

In areas where expansive or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge roof drainage to the ground surface not less than 5 feet (1524 mm) from foundation walls or to an approved drainage system.

Wood and wood-based products used for load-supporting purposes shall conform to the applicable provisions of this section.
Sawn lumber shall be identified by a grade mark of an accredited lumber grading or inspection agency and have design values certified by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted.
Approved end-jointed lumber identified by a grade mark conforming to Section R802.1.1 shall be permitted to be used interchangeably with solid-sawn members of the same species and grade. End-jointed lumber used in an assembly required elsewhere in this code to have a fire-resistance rating shall have the designation “Heat-Resistant Adhesive” or “HRA” included in its grade mark.
Glued laminated timbers shall be manufactured and identified as required in ANSI/AITC A190.1 and ASTM D3737.
Structural log members shall comply with the provisions of ICC 400.
Structural capacities for structural composite lumber shall be established and monitored in accordance with ASTM D5456.
Fire-retardant-treated wood (FRTW) 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 shows no evidence of significant progressive combustion where the test is continued for an additional 20-minute period. In addition, the flame front shall not progress more than 10.5 feet (3200 mm) beyond the center line 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) (344.7 kPa).
For wood products produced 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.
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 R802.1.5. Testing of only the front and back faces of wood structural panels shall be permitted.

Fire-retardant-treated lumber and wood structural panels shall be labeled. The label shall contain:

  1. The identification mark of an approved agency in accordance with Section 1703.5 of the Florida Building Code, Building.
  2. Identification of the treating manufacturer.
  3. The name of the fire-retardant treatment.
  4. The species of wood treated.
  5. Flame spread index and smoke-developed index.
  6. Method of drying after treatment.
  7. Conformance to applicable standards in accordance with Sections R802.1.5.5 through R802.1.5.10.
  8. For FRTW exposed to weather, or a damp or wet location, 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 R802.1 shall be adjusted for fire-retardant-treated wood. Adjustments to design values shall be based upon 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 their treatment.
For each species of wood treated, the effect of the treatment and 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 not an increase in the listed flame spread index as defined in Section R802.1.5 when subjected to ASTM D2898.
Interior fire-retardant-treated wood shall have a 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 R802.1.5.6 or R802.1.5.7. 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 R802.1.5.6 for plywood and R802.1.5.7 for lumber.
Cross-laminated timber shall be manufactured and identified as required by ANSI/APA PRG 320.
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.
The framing details required in Section R802 apply to roofs having a minimum slope of three units vertical in 12 units horizontal (25-percent slope) or greater. Roof-ceilings shall be designed and constructed in accordance with the provisions of this chapter and Figures R606.11(1), R606.11(2) and R606.11(3) or in accordance with AWC NDS. Components of roof-ceilings shall be fastened in accordance with Table R602.3(1).
Rafters shall be framed not more than 11/2-inches (38 mm) offset from each other to ridge board or directly opposite from each other with a gusset plate as a tie. Ridge board shall be not less than 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. At valleys and hips there shall be a valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent slope), structural members that support rafters and ceiling joists, such as ridge beams, hips and valleys, shall be designed as beams.

Ceiling joists and rafters shall be nailed to each other in accordance with Table R802.5.1(9), and the rafter shall be nailed to the top wall plate in accordance with Table R602.3(1). Ceiling joists shall be continuous or securely joined in accordance with Table R802.5.1(9) where they meet over interior partitions and are nailed to adjacent rafters to provide a continuous tie across the building where such joists are parallel to the rafters.

Where ceiling joists are not connected to the rafters at the top wall plate, joists connected higher in the attic shall be installed as rafter ties, or rafter ties shall be installed to provide a continuous tie. Where ceiling joists are not parallel to rafters, rafter ties shall be installed. Rafter ties shall be not less than 2 inches by 4 inches (51 mm by 102 mm) (nominal), installed in accordance with the connection requirements in Table R802.5.1(9), or connections of equivalent capacities shall be provided. Where ceiling joists or rafter ties are not provided, the ridge formed by these rafters shall be supported by a wall or girder designed in accordance with accepted engineering practice.

Collar ties or ridge straps to resist wind uplift shall be connected in the upper third of the attic space in accordance with Table R602.3(1).

Collar ties shall be not less than 1 inch by 4 inches (25 mm by 102 mm) (nominal), spaced not more than 4 feet (1219 mm) on center.

Ends of ceiling joists shall be lapped not less than 3 inches (76 mm) or butted over bearing partitions or beams and toenailed to the bearing member. Where ceiling joists are used to provide resistance to rafter thrust, lapped joists shall be nailed together in accordance with Table R802.5.1(9) and butted joists shall be tied together in a manner to resist such thrust. Joists that do not resist thrust shall be permitted to be nailed in accordance with Table R602.3(1).
Blocking shall be a minimum of utility grade lumber.

Spans for ceiling joists shall be in accordance with Tables R802.4(1) and R802.4(2). For other grades and species and for other loading conditions, refer to the AWC STJR.

TABLE R802.4(1)

CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable attics without storage, live load = 10 psf, L/Δ = 240)

CEILING JOIST
SPACING (inches)
SPECIES AND GRADEDEAD LOAD = 5 psf
2 × 42 × 62 × 82 × 10
Maximum ceiling joist spans
(feet - inches)(feet - inches)(feet - inches)(feet - inches)
12Douglas fir-larchSS13-220-8Note aNote a
Douglas fir-larch#112-819-11Note aNote a
Douglas fir-larch#212-519-625-8Note a
Douglas fir-larch#311-116-320-725-2
Hem-firSS12-519-625-8Note a
Hem-fir#112-219-125-2Note a
Hem-fir#211-718-224-0Note a
Hem-fir#310-1015-1020-124-6
Southern pineSS12-1120-3Note aNote a
Southern pine#112-519-625-8Note a
Southern pine#211-1018-824-7Note a
Southern pine#310-114-1118-922-9
Spruce-pine-firSS12-219-125-2Note a
Spruce-pine-fir#111-1018-824-7Note a
Spruce-pine-fir#211-1018-824-7Note a
Spruce-pine-fir#310-1015-1020-124-6
16Douglas fir-larchSS11-1118-924-8Note a
Douglas fir-larch#111-618-123-10Note a
Douglas fir-larch#211-317-823-4Note a
Douglas fir-larch#39-714-117-1021-9
Hem-firSS11-317-823-4Note a
Hem-fir#111-017-422-10Note a
Hem-fir#210-616-621-9Note a
Hem-fir#39-513-917-521-3
Southern pineSS11-918-524-3Note a
Southern pine#111-317-823-10Note a
Southern pine#210-916-1121-725-7
Southern pine#38-912-1116-319-9
Spruce-pine-firSS11-017-422-10Note a
Spruce-pine-fir#110-916-1122-4Note a
Spruce-pine-fir#210-916-1122-4Note a
Spruce-pine-fir#39-513-917-521-3
19.2Douglas fir-larchSS11-317-823-3Note a
Douglas fir-larch#110-1017-022-5Note a
Douglas fir-larch#210-716-821-426-0
Douglas fir-larch#38-912-1016-319-10
Hem-firSS10-716-821-11Note a
Hem-fir#110-416-421-6Note a
Hem-fir#29-1115-720-625-3
Hem-fir#38-712-615-1019-5
Southern -pineSS11-017-422-10Note a
Southern pine#110-716-822-0Note a
Southern pine#210-215-719-823-5
Southern pine#38-011-914-1018-0
Spruce-pine-firSS10-416-421-6Note a
Spruce-pine-fir#110-215-1121-025-8
Spruce-pine-fir#210-215-1121-025-8
Spruce-pine-fir#38-712-615-1019-5
24Douglas fir-larchSS10-516-421-7Note a
Douglas fir-larch#110-015-920-124-6
Douglas fir-larch#29-1015-019-123-3
Douglas fir-larch#37-1011-614-717-9
Hem-firSS9-1015-620-5Note a
Hem-fir#19-815-219-1024-3
Hem-fir#29-214-518-622-7
Hem-fir#37-811-214-217-4
Southern pineSS10-316-121-2Note a
Southern pine#19-1015-620-524-0
Southern pine#29-313-1117-720-11
Southern pine#37-210-613-316-1
Spruce-pine-firSS9-815-219-1125-5
Spruce-pine-fir#19-514-918-922-11
Spruce-pine-fir#29-514-918-922-11
Spruce-pine-fir#37-811-214-217-4

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. Span exceeds 26 feet in length.

TABLE R802.4(2)

CEILING JOIST SPANS FOR COMMON LUMBER SPECIES (Uninhabitable attics with limited storage, live load = 20 psf, L/Δ = 240)

CEILING JOIST
SPACING (inches)
SPECIES AND GRADEDEAD LOAD = 10 psf
2 × 42 × 62 × 82 × 10
Maximum ceiling joist spans
(feet - inches)(feet - inches)(feet - inches)(feet - inches)
12Douglas fir-larchSS10-516-421-7Note a
Douglas fir-larch#110-015-920-124-6
Douglas fir-larch#29-1015-019-123-3
Douglas fir-larch#37-1011-614-717-9
Hem-firSS9-1015-620-5Note a
Hem-fir#19-815-219-1024-3
Hem-fir#29-214-518-622-7
Hem-fir#37-811-214-217-4
Southern pineSS10-316-121-2Note a
Southern pine#19-1015-620-524-0
Southern pine#29-313-1117-720-11
Southern pine#37-210-613-316-1
Spruce-pine-firSS9-815-219-1125-5
Spruce-pine-fir#19-514-918-922-11
Spruce-pine-fir#29-514-918-922-11
Spruce-pine-fir#37-811-214-217-4
16Douglas fir-larchSS9-614-1119-725-0
Douglas fir-larch#19-113-917-521-3
Douglas fir-larch#28-1113-016-620-2
Douglas fir-larch#36-109-1112-715-5
Hem-firSS8-1114-118-623-8
Hem-fir#18-913-717-221-0
Hem-fir#28-412-816-019-7
Hem-fir#36-89-812-415-0
Southern pineSS9-414-719-324-7
Southern pine#18-1114-017-920-9
Southern pine#28-012-015-318-1
Southern pine#36-29-211-614-0
Spruce-pine-firSS8-913-918-123-1
Spruce-pine-fir#18-712-1016-319-10
Spruce-pine-fir#28-712-1016-319-10
Spruce-pine-fir#36-89-812-415-0
19.2Douglas fir-larchSS8-1114-018-523-7
Douglas fir-larch#18-712-615-1019-5
Douglas fir-larch#28-211-1115-118-5
Douglas fir-larch#36-29-111-614-1
Hem-firSS8-513-317-522-3
Hem-fir#18-312-415-819-2
Hem-fir#27-1011-714-817-10
Hem-fir#36-18-1011-313-8
Southern pineSS8-913-918-223-1
Southern pine#18-512-916-218-11
Southern pine#27-411-013-1116-6
Southern pine#35-88-410-612-9
Spruce-pine-firSS8-312-1117-121-8
Spruce-pine-fir#18-011-914-1018-2
Spruce-pine-fir#28-011-914-1018-2
Spruce-pine-fir#36-18-1011-313-8
24Douglas fir-larchSS8-313-017-221-3
Douglas fir-larch#17-811-214-217-4
Douglas fir-larch#27-310-813-616-5
Douglas fir-larch#35-78-110-312-7
Hem-firSS7-1012-316-220-6
Hem-fir#17-711-114-017-1
Hem-fir#27-110-413-116-0
Hem-fir#35-57-1110-012-3
Southern pineSS8-112-916-1021-6
Southern pine#17-811-514-616-11
Southern pine#26-79-1012-614-9
Southern pine#35-17-59-511-5
Spruce-pine-firSS7-812-015-1019-5
Spruce-pine-fir#17-210-613-316-3
Spruce-pine-fir#27-210-613-316-3
Spruce-pine-fir#35-57-1110-012-3

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. Span exceeds 26 feet in length.
Spans for rafters shall be in accordance with Tables R802.5.1(1) through R802.5.1(8). For other grades and species and for other loading conditions, refer to the AWC STJR. The span of each rafter shall be measured along the horizontal projection of the rafter.

Installation of purlins to reduce the span of rafters is permitted as shown in Figure R802.5.1. Purlins shall be sized not less than the required size of the rafters that they support. Purlins shall be continuous and shall be supported by 2-inch by 4-inch (51 mm by 102 mm) braces installed to bearing walls at a slope not less than 45 degrees (0.79 rad) from the horizontal. The braces shall be spaced not more than 4 feet (1219 mm) on center and the unbraced length of braces shall not exceed 8 feet (2438 mm).

TABLE R802.5.1(1)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Roof live load = 20 psf, ceiling not attached to rafters, L/Δ = 180)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
12Douglas fir-larchSS11-618-023-9Note bNote b11-618-023-9Note bNote b
Douglas fir-larch#111-117-422-5Note bNote b10-615-419-523-9Note b
Douglas fir-larch#210-1016-1021-426-0Note b10-014-718-522-626-0
Douglas fir-larch#38-912-1016-319-1023-07-711-114-117-219-11
Hem-firSS10-1017-022-5Note bNote b10-1017-022-5Note bNote b
Hem-fir#110 -716-822-0Note bNote b10-415-219-223-5Note b
Hem-fir#210-115-1120-825-3Note b9-814-217-1121-1125-5
Hem-fir#38-712-615-1019-522-67-510-1013-916-919-6
Southern pineSS11-317-823-4Note bNote b11-317-823-4Note bNote b
Southern pine#110-1017-022-5Note bNote b10-615-819-1023-2Note b
Southern pine#210-415-719-823-5Note b9-013-617-120-323-10
Southern pine#38-011-914-1018-021-46-1110-212-1015-718-6
Spruce-pine-firSS10-716-821-11Note bNote b10-716-821-9Note bNote b
Spruce-pine-fir#110-416-321-025-8Note b9-1014-418-222-325-9
Spruce-pine-fir#210-416-321-025-8Note b9-1014-418-222-325-9
Spruce-pine-fir#38-712-615-1019-522-67-510-1013-916-919-6
16Douglas fir-larchSS10-516-421-7Note bNote b10-516-320-725-2Note b
Douglas fir-larch#110-015-419-523-9Note b9-113-316-1020-723-10
Douglas fir-larch#29-1014-718-522-626-08-712-716-019-622-7
Douglas fir-larch#37-711-114-117-219-116-79-812-1214-1117-3
Hem-firSS9-1015-620-5Note bNote b9-1015-619-1124-4Note b
Hem-fir#19-815-219-223-5Note b9-013-116-720-423-7
Hem-fir#29-214-217-1121-1125-58-512-315-618-1122-0
Hem-fir#37-510-1013-916-919-66-59-511-1114-616-10
Southern pineSS10-316-121-2Note bNote b10-316-121-225-7Note b
Southern pine#19-1015-619-1023-2Note b9-113-717-220-123-10
Southern pine#29-013-617-120-323-107-911-814-917-620-8
Southern pine#36-1110-212-1015-718-66-08-1011-213-616-0
Spruce-pine-firSS9-815-219-1125-5Note b9-814-1018-1023-0Note b
Spruce-pine-fir#19-514-418-222-325-98-612-515-919-322-4
Spruce-pine-fir#29-514-418-222-325-98-612-515-919-322-4
Spruce-pine-fir#37-510-1013-916-919-66-59-511-1114-616-10
19.2Douglas fir-larchSS9-1015-520-425-11Note b9-1014-1018-1023-0Note b
Douglas fir-larch#19-514-017-921-825-28-412-215-418-921-9
Douglas fir-larch#29-113-316-1020-723-107-1011-614-717-1020-8
Douglas fir-larch#36-1110-212-1015-818-36-08-911-212-715-9
Hem-firSS9-314-719-224-6Note b9-314-418-222-325-9
Hem-fir#19-113-1017-621-524-108-212-015-218-621-6
Hem-fir#28-812-1116-420-023-27-811-214-217-420-1
Hem-fir#36-99-1112-715-417-95-108-710-1013-315-5
Southern pineSS9-815-219-1125-5Note b9-815-219-723-4Note b
Southern pine#19-314-318-121-225-28-412-415-818-421-9
Southern pine#28-212-315-718-621-97-110-813-616-018-10
Southern pine#36-49-411-914-316-105-68-110-212-414-7
Spruce-pine-firSS9-114-318-923-11Note b9-113-717-221-024-4
Spruce-pine-fir#18-1013-116-720-323-67-911-414-417-720-4
Spruce-pine-fir#28-1013-116-720-323-67-911-414-417-720-4
Spruce-pine-fir#36-99-1112-715-417-95-108-710-1013-315-5
24Douglas fir-larchSS9-114-418-1023-9Note b9-113-316-1020-723-10
Douglas fir-larch#18-712-615-1019-522-67-510-1013-916-919-6
Douglas fir-larch#28-211-1115-118-521-47-010-413-015-1118-6
Douglas fir-larch#36-29-111-614-116-35-47-1010-012-214-1
Hem-firSS8-713-617-1022-9Note b8-712-1016-319-1023-0
Hem-fir#18-512-415-819-222-27-410-913-716-719-3
Hem-fir#27-1111-714-817-1020-96-1010-012-815-617-11
Hem-fir#36-18-1011-313-815-115-37-89-911-1013-9
Southern pineSS8-1114-118-623-8Note b8-1113-1017-620-1024-8
Southern pine#18-712-916-218-1122-67-511-114-016-519-6
Southern pine#27-411-013-1116-619-66-49-612-114-416-10
Southern pine#35-88-410-612-915-14-117-39-111-013-1
Spruce-pine-firSS8-513-317-521-825-28-412-215-418-921-9
Spruce-pine-fir#18-011-914-1018-221-06-1110-212-1015-818-3
Spruce-pine-fir#28-011-914-1018-221-06-1110-212-1015-818-3
Spruce-pine-fir#36-18-1011-313-815-115-37-89-911-1013-9

Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

  2. Span exceeds 26 feet in length.

TABLE R802.5.1(2)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Roof live load = 20 psf, ceiling attached to rafters, L/Δ = 240)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
12Douglas fir-larchSS10-516-421-7Note bNote b10-516-421-7Note bNote b
Douglas fir-larch#110-015-920-10Note bNote b10-015-419-523-9Note b
Douglas fir-larch#29-1015-620-526-0Note b9-1014-718-522-626-0
Douglas fir-larch#38-912-1016-319-1023-07-711-114-117-219-11
Hem-firSS9-1015-620-5Note bNote b9-1015-620-5Note bNote b
Hem-fir#19-815-219-1125-5Note b9-815-219-223-5Note b
Hem-fir#29-214-519-024-3Note b9-214-217-1121-1125-5
Hem-fir#38-712-615-1019-522-67-510-1013-916-919-6
Southern pineSS10-316-121-2Note bNote b10-316-121-2Note bNote b
Southern pine#19-1015-620-5Note bNote b9-1015-619-1023-2Note b
Southern pine#29-514-919-623-5Note b9-013-617-120-323-10
Southern pine#38-011-914-1018-021-46-1110-212-1015-718-6
Spruce-pine-firSS9-815-219-1125-5Note b9-815-219-1125-5Note b
Spruce-pine-fir#19-514-919-624-10Note b9-514-418-222-325-9
Spruce-pine-fir#29-514-919-624-10Note b9-514-418-222-325-9
Spruce-pine-fir#38-712-615-1019-522-67-510-1013-916-919-6
16Douglas fir-larchSS9-614-1119-725-0Note b9-614-1119-725-0Note b
Douglas fir-larch#19-114-418-1123-9Note b9-113-316-1020-723-10
Douglas fir-larch#28-1114-118-522-626-08-712-716-019-622-7
Douglas fir-larch#37-711-114-117-219-116-79-812-214-1117-3
Hem-firSS8-1114-118-623-8Note b8-1114-118-623-8Note b
Hem-fir#18-913-918-123-1Note b8-913-116-720-423-7
Hem-fir#28-413-117-321-1125-58-412-315-618-1122-0
Hem-fir#37-510-1013-916-919-66-59-511-1114-616-10
Southern pineSS9-414-719-324-7Note b9-414-719-324-7Note b
Southern pine#18-1114-118-623-2Note b8-1113-717-220-123-10
Southern pine#28-713-517-120-323-107-911-814-917-620-8
Southern pine#36-1110-212-1015-718-66-08-1011-213-616-0
Spruce-pine-firSS8-913-918-123-1Note b8-913-918-123-0Note b
Spruce-pine-fir#18-713-517-922-325-98-612-515-919-322-4
Spruce-pine-fir#28-713-517-922-325-98-612-515-919-322-4
Spruce-pine-fir#37-510-1013-916-919-66-59-511-1114-616-10
19.2Douglas fir-larchSS8-1114-018-523-7Note b8-1114-018-523-0Note b
Douglas fir-larch#18-713-617-921-825-28-412-215-418-921-9
Douglas fir-larch#28-513-316-1020-723-107-1011-614-717-1020-8
Douglas fir-larch#36-1110-212-1015-818-36-08-911-213-715-9
Hem-firSS8-513-317-522-3Note b8-513-317-522-325-9
Hem-fir#18-312-1117-121-524-108-212-015-218-621-6
Hem-fir#27-1012-416-320-023-27-811-214-217-420-1
Hem-fir#36-99-1112-715-417-95-108-710-1013-315-5
Southern pineSS8-913-918-223-1Note b8-913-918-223-1Note b
Southern pine#18-513-317-521-225-28-412-415-818-421-9
Southern pine#28-112-315-718-621-97-110-813-616-018-10
Southern pine#36-49-411-914-316-105-68-110-212-414-7
Spruce-pine-firSS8-312-1117-121-9Note b8-312-1117-121-024-4
Spruce-pine-fir#18-112-816-720-323-67-911-414-417-720-4
Spruce-pine-fir#28-112-816-720-323-67-911-414-417-720-4
Spruce-pine-fir#36-99-1112-715-417-95-108-710-1013-315-5
24Douglas fir-larchSS8-313-017-221-10Note b8-313-016-1020-723-10
Douglas fir-larch#18-012-615-1019-522-67-510-1013-916-919-6
Douglas fir-larch#27-1011-1115-118-521-47-010-413-015-1118-6
Douglas fir-larch#36-29-111-614-116-35-47-1010-012-214-1
Hem-firSS7-1012-316-220-825-17-1012-316-219-1023-0
Hem-fir#17-812-015-819-222-27-410-913-716-719-3
Hem-fir#27-311-514-817-1020-96-1010-012-815-617-11
Hem-fir#36-18-1011-313-815-115-37-89-911-1013-9
Southern pineSS8-112-916-1021-6Note b8-112-916-1020-1024-8
Southern pine#17-1012-316-218-1122-67-511-114-016-519-6
Southern pine#27-411-013-1116-619-66-49-612-114-416-10
Southern pine#35-88-410-612-915-14-117-39-111-013-1
Spruce-pine-firSS7-812-015-1020-224-77-812-015-418-921-9
Spruce-pine-fir#17-611-914-1018-221-06-1110-212-1015-818-3
Spruce-pine-fir#27-611-914-1018-221-06-1110-212-1015-818-3
Spruce-pine-fir#36-18-1011-313-815-115-37-89-911-1013-9
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

  2. Span exceeds 26 feet in length.

TABLE R802.5.1(3)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground snow load = 30 psf, ceiling not attached to rafters, L/Δ = 180)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
12Douglas fir-larchSS10-015-920-9Note bNote b10-015-920-524-11Note b
Douglas fir-larch#19-814-918-822-9Note b9-013-216-820-423-7
Douglas fir-larch#29-614-017-821-725-18-612-615-1019-422-5
Douglas fir-larch#37-310-813-616-619-26-69-612-114-917-1
Hem-firSS9-614-1019-725-0Note b9-614-1019-724-1Note b
Hem-fir#19-314-618-522-626-08-1113-016-620-123-4
Hem-fir#28-1013-717-221-024-48-412-215-418-921-9
Hem-fir#37-110-513-216-118-86-49-411-914-516-8
Southern pineSS9-1015-620-5Note bNote b9-1015-620-525-4Note b
Southern pine#19-614-1019-022-3Note b9-013-517-019-1123-7
Southern pine#28-712-1116-419-522-107-811-714-817-420-5
Southern pine#36-79-912-415-017-95-118-911-013-515-10
Spruce-pine-firSS9-314-719-224-6Note b9-314-718-822-9Note b
Spruce-pine-fir#19-113-917-521-424-88-512-415-719-122-1
Spruce-pine-fir#29-113-917-521-424-88-512-415-719-122-1
Spruce-pine-fir#37-110-513-216-118-86-49-411-914-516-8
16Douglas fir-larchSS9-114-418-1024-1Note b9-114-017-821-725-1
Douglas fir-larch#18-912-916-219-922-107-1011-514-517-820-5
Douglas fir-larch#28-312-115-418-921-87-510-1013-816-919-5
Douglas fir-larch#36-49-311-814-316-75-88-310-612-914-10
Hem-firSS8-713-617-1022-9Note b8-713-617-120-1024-2
Hem-fir#18-512-715-1119-622-77-811-314-317-520-2
Hem-fir#28-011-914-1118-221-17-210-613-416-318-10
Hem-fir#36-29-011-513-1116-25-68-110-312-614-6
Southern pineSS8-1114-118-623-8Note b8-1114-118-51-1125-11
Southern pine#18-713-016-619-322-107-1011-714-917-320-5
Southern pine#27-611-214-216-1019-106-810-012-815-117-9
Southern pine#35-98-610-813-015-45-27-79-711-713-9
Spruce-pine-firSS8-513-317-522-125-78-512-916-219-922-10
Spruce-pine-fir#18-211-1115-118-521-57-310-813-616-619-2
Spruce-pine-fir#28-211-1115-118-521-57-310-813-616-619-2
Spruce-pine-fir#36-29-011-513-1116-25-68-110-312-614-6
19.2Douglas fir-larchSS8-713-617-922-125-78-712-916-219-922-10
Douglas fir-larch#17-1111-814-918-020-117-110-513-216-118-8
Douglas fir-larch#27-711-014-017-119-106-99-1012-615-317-9
Douglas fir-larch#35-98-510-813-115-25-27-79-711-813-6
Hem-firSS8-112-916-921-424-88-112-415-719-122-1
Hem-fir#17-1011-614-717-920-77-010-313-015-1118-5
Hem-fir#27-410-913-716-719-36-79-712-214-1017-3
Hem-fir#35-78-310-512-914-95-07-49-411-513-2
Southern pineSS8-513-317-522-3Note b8-513-316-1020-023-7
Southern pine#18-011-1015-117-720-117-110-713-515-918-8
Southern pine#26-1010-212-1115-418-16-19-211-713-916-2
Southern pine#35-37-99-911-1014-04-86-118-910-712-6
Spruce-pine-firSS7-1112-516-520-223-47-1111-814-918-020-11
Spruce-pine-fir#17-510-1113-916-1019-66-89-912-415-117-6
Spruce-pine-fir#27-510-1113-916-1019-66-89-912-415-117-6
Spruce-pine-fir#35-78-310-512-914-95-07-49-411-513-2
24Douglas fir-larchSS8-012-616-219-922-107-1011-514-517-820-5
Douglas fir-larch#17-110-513-216-118-86-49-411-914-516-8
Douglas fir-larch#26-99-1012-615-317-96-08-1011-213-815-10
Douglas fir-larch#35-27-79-711-813-64-76-98-710-512-1
Hem-firSS7-611-1015-719-122-17-611-013-1117-019-9
Hem-fir#17-010-313-015-1118-56-39-211-814-316-6
Hem-fir#26-79-712-214-1017-35-108-710-1013-315-5
Hem-fir#35-07-49-411-513-24-66-78-410-211-10
Southern pineSS7-1012-316-220-023-77-1011-1015-017-1121-2
Southern pine#17-110-713-515-918-86-49-612-014-116-8
Southern pine#26-19-211-713-916-25-58-210-412-314-6
Southern pine#34-86-118-910-712-64-26-27-109-611-2
Spruce-pine-firSS7-411-714-918-020-117-110-513-216-118-8
Spruce-pine-fir#16-89-912-415-117-65-118-811-013-615-7
Spruce-pine-fir#26-89-912-415-117-65-118-811-013-615-7
Spruce-pine-fir#35-07-49-411-513-24-66-78-410-211-10
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

  2. Span exceeds 26 feet in length.

TABLE R802.5.1(4)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground snow load = 50 psf, ceiling not attached to rafters, L/Δ = 180)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
12Douglas fir-larchSS8-513-317-622-426-08-513-317-321-124-5
Douglas fir-larch#18-212-015-318-721-77-711-214-117-320-0
Douglas fir-larch#27-1011-514-517-820-57-310-713-416-418-11
Douglas fir-larch#36-08-911-013-615-75-68-110-312-614-6
Hem-firSS8-012-616-621-125-68-012-616-620-423-7
Hem-fir#17-1011-1015-018-421-37-611-013-1117-019-9
Hem-fir#27-511-114-017-219-117-010-313-015-1018-5
Hem-fir#35-108-610-913-215-35-57-1010-012-214-1
Southern pineSS8-413-117-221-11Note b8-413-117-221-525-3
Southern pine#18-012-315-618-221-77-711-414-516-1020-0
Southern pine#27-010-613-415-1018-86-69-912-414-817-3
Southern pine#35-58-010-112-314-65-07-59-411-413-5
Spruce-pine-firSS7-1012-316-220-824-17-1012-315-919-322-4
Spruce-pine-fir#17-811-314-317-520-27-110-513-216-118-8
Spruce-pine-fir#27-811-314-317-520-27-110-513-216-118-8
Spruce-pine-fir#35-108-610-913-215-35-57-1010-012-214-1
16Douglas fir-larchSS7-812-115-1119-922-107-811-1014-1118-321-2
Douglas fir-larch#17-110-513-216-118-86-79-812-214-1117-3
Douglas fir-larch#26-99-1012-615-317-96-39-211-714-216-5
Douglas fir-larch#35-27-79-711-1813-64-97-08-1010-1012-6
Hem-firSS7-311-515-019-122-17-311-514-517-820-5
Hem-fir#17-010-313-015-1118-56-69-612-114-917-1
Hem-fir#26-79-712-214-1017-36-18-1111-313-915-11
Hem-fir#35-07-49-411-513-24-86-108-810-612-3
Southern pineSS7-611-1015-719-1123-77-611-1015-718-621-10
Southern pine#17-110-713-515-918-86-79-1012-514-717-3
Southern pine#26-19-211-713-916-25-88-510-912-915-0
Southern pine#34-86-118-910-712-64-46-58-19-1011-7
Spruce-pine-firSS7-111-214-818-020-117-110-913-815-1119-4
Spruce-pine-fir#16-89-912-415-117-66-29-011-513-1116-2
Spruce-pine-fir#26-89-912-415-117-66-29-011-513-1116-2
Spruce-pine-fir#35-07-49-411-513-24-86-108-810-612-3
19.2Douglas fir-larchSS7-311-414-918-020-117-310-913-816-819-4
Douglas fir-larch#16-69-612-014-817-16-08-1011-213-715-9
Douglas fir-larch#26-29-011-513-1116-25-88-410-912-1115-0
Douglas fir-larch#34-86-118-910-812-44-46-48-19-1011-5
Hem-firSS6-1010-914-217-520-26-1010-513-216-118-8
Hem-fir#16-59-511-1114-616-108-118-811-013-515-7
Hem-fir#26-08-911-113-715-95-78-110-312-714-7
Hem-fir#34-76-98-610-512-14-36-37-119-711-2
Southern pineSS7-111-214-818-321-77-111-214-216-1120-0
Southern pine#16-69-812-314-417-16-09-011-413-415-9
Southern pine#25-78-410-712-614-95-27-99-911-713-8
Southern pine#34-36-48-09-811-54-05-107-48-1110-7
Spruce-pine-firSS6-810-613-516-519-16-89-1012-515-317-8
Spruce-pine-fir#16-18-1111-313-915-115-78-310-512-914-9
Spruce-pine-fir#26-18-1111-313-915-115-78-310-512-914-9
Spruce-pine-fir#34-76-98-610-512-14-36-37-119-711-2
24Douglas fir-larchSS6-810-513-216-118-86-79-812-214-1117-3
Douglas fir-larch#15-108-610-913-215-35-57-1010-012-214-1
Douglas fir-larch#25-68-110-312-614-65-17-69-511-713-5
Douglas fir-larch#34-36-27-109-611-13-115-87-38-1010-3
Hem-firSS6-49-1112-915-718-06-49-411-914-516-8
Hem-fir#15-98-510-813-015-18-47-99-1012-013-11
Hem-fir#25-47-109-1112-114-14-117-39-211-313-0
Hem-fir#34-16-07-79-410-93-105-77-18-710-0
Southern pineSS6-710-413-816-419-36-710-012-815-217-10
Southern pine#15-108-811-012-1015-35-58-010-211-1114-1
Southern pine#25-07-59-511-313-24-76-118-910-512-3
Southern pine#33-105-87-18-810-33-65-36-78-09-6
Spruce-pine-firSS6-29-612-014-817-16-08-1011-213-715-9
Spruce-pine-fir#15-57-1110-112-414-35-07-49-411-513-2
Spruce-pine-fir#25-57-1110-112-414-35-07-49-411-513-2
Spruce-pine-fir#34-16-07-79-410-93-105-77-18-710-0
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

  2. Span exceeds 26 feet in length.

TABLE R802.5.1(5)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground snow load = 30 psf, ceiling attached to rafters, L/Δ = 240)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
12Douglas fir-larchSS9-114-418-1024-1Note b9-114-418-1024-1Note b
Douglas fir-larch#18-913-918-222-9Note b8-913-216-820-423-7
Douglas fir-larch#28-713-617-821-725-18-612-615-1019-422-5
Douglas fir-larch#37-310-813-616-619-26-69-612-114-917-1
Hem-firSS8-713-617-1022-9Note b8-713-617-1022-9Note b
Hem-fir#18-513-317-522-326-08-513-016-620-123-4
Hem-fir#28-012-716-721-024-48-012-215-418-921-9
Hem-fir#37-110-513-216-118-86-49-411-914-516-8
Southern pineSS8-1114-118-623-8Note b8-1114-118-623-8Note b
Southern pine#18-713-617-1022-3Note b8-713-517-019-1123-7
Southern pine#28-312-1116-419-522-107-811-714-817-420-5
Southern pine#36-79-912-415-017-95-118-911-013-515-10
Spruce-pine-firSS8-513-317-522-3Note b8-513-317-522-3Note b
Spruce-pine-fir#18-312-1117-021-424-88-312-415-719-122-1
Spruce-pine-fir#28-312-1117-021-424-88-312-415-719-122-1
Spruce-pine-fir#37-110-513-216-118-86-49-411-914-516-8
16Douglas fir-larchSS8-313-017-221-10Note b8-313-017-221-725-1
Douglas fir-larch#18-012-616-219-922-107-1011-514-517-820-5
Douglas fir-larch#27-1012-115-418-921-87-510-1013-816-919-5
Douglas fir-larch#36-49-311-814-316-75-88-310-612-914-10
Hem-firSS7-1012-316-220-825-17-1012-316-220-824-2
Hem-fir#17-812-015-1019-622-77-811-314-317-520-2
Hem-fir#27-311-514-1118-221-17-210-613-416-318-10
Hem-fir#36-29-011-513-1116-25-68-110-312-614-6
Southern pineSS8-112-916-1021-6Note b8-112-916-1021-625-11
Southern pine#17-1012-316-219-322-107-1011-714-917-320-5
Southern pine#27-611-214-216-1019-106-810-012-815-117-9
Southern pine#35-98-610-813-015-45-27-79-711-713-9
Spruce-pine-firSS7-812-015-1020-224-77-812-015-1019-922-10
Spruce-pine-fir#17-611-915-118-521-57-310-813-616-619-2
Spruce-pine-fir#27-611-915-118-521-57-310-813-616-619-2
Spruce-pine-fir#36-29-011-513-1116-25-68-110-312-614-6
19.2Douglas fir-larchSS7-912-316-120-725-07-912-316-119-922-10
Douglas fir-larch#17-611-814-918-020-117-110-513-216-118-8
Douglas fir-larch#27-411-014-017-119-106-99-112-615-317-9
Douglas fir-larch#35-98-510-813-115-25-27-79-711-813-6
Hem-firSS7-411-715-319-523-77-411-715-319-122-1
Hem-fir#17-211-414-717-920-77-016-313-015-1118-5
Hem-fir#26-1010-913-716-719-36-79-712-214-1017-3
Hem-fir#35-78-310-512-914-95-07-49-411-513-2
Southern pineSS7-812-015-1020-224-77-812-015-1020-023-7
Southern pine#17-411-715-117-720-117-110-713-515-918-8
Southern pine#26-1010-212-1115-418-16-19-211-713-916-2
Southern pine#35-37-99-911-1014-04-86-118-910-712-6
Spruce-pine-firSS7-211-414-1119-023-17-211-414-918-020-11
Spruce-pine-fir#17-010-1113-916-1019-66-89-912-415-117-6
Spruce-pine-fir#27-010-1113-916-1019-66-89-912-415-117-6
Spruce-pine-fir#35-78-310-512-914-95-07-49-411-513-2
24Douglas fir-larchSS7-311-415-019-122-107-311-414-517-820-5
Douglas fir-larch#17-010-513-216-118-86-49-411-914-516-8
Douglas fir-larch#26-99-1012-615-317-96-08-1011-213-815-10
Douglas fir-larch#35-27-79-711-813-64-76-98-710-512-1
Hem-firSS6-1010-914-218-021-116-1010-913-1117-019-9
Hem-fir#16-810-313-015-1118-56-39-211-814-316-6
Hem-fir#26-49-712-214-1017-35-108-710-1013-315-5
Hem-fir#35-07-49-411-513-24-66-78-410-211-10
Southern pineSS7-111-214-818-922-107-111-214-817-1121-2
Southern pine#16-1010-713-515-918-86-49-612-014-116-8
Southern pine#26-19-211-713-916-25-58-210-412-314-6
Southern pine#34-86-118-910-712-64-26-27-109-611-2
Spruce-pine-firSS6-810-613-1017-820-116-810-513-216-118-8
Spruce-pine-fir#16-69-912-415-117-65-118-811-013-615-7
Spruce-pine-fir#26-69-912-415-117-65-118-811-013-615-7
Spruce-pine-fir#35-07-49-411-513-24-66-78-410-211-10
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

  2. Span exceeds 26 feet in length.

TABLE R802.5.1(6)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground snow load = 50 psf, ceiling attached to rafters, L/Δ = 240)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
12Douglas fir-larchSS7-812-115-1120-324-87-812-115-1120-324-5
Douglas fir-larch#17-511-715-318-721-77-511-214-117-320-0
Douglas fir-larch#27-311-514-517-820-57-310-713-416-418-11
Douglas fir-larch#36-08-911-013-615-75-68-110-312-614-6
Hem-firSS7-311-515-019-223-47-311-515-019-223-4
Hem-fir#17-111-214-818-421-37-111-013-1117-019-9
Hem-fir#26-910-814-017-219-116-910-313-015-1018-5
Hem-fir#35-108-610-913-215-35-57-1010-012-214-1
Southern pineSS7-611-1015-719-1124-37-611-1015-719-1124-3
Southern pine#17-311-515-018-221-77-311-414-516-1020-0
Southern pine#26-1110-613-415-1018-86-69-912-414-817-3
Southern pine#35-58-010-112-314-65-07-59-411-413-5
Spruce-pine-firSS7-111-214-818-922-107-111-214-818-922-4
Spruce-pine-fir#16-1110-1114-317-520-26-1110-513-216-118-8
Spruce-pine-fir#26-1110-1114-317-520-26-1110-513-216-118-8
Spruce-pine-fir#35-108-610-913-215-35-57-1010-012-214-1
16Douglas fir-larchSS7-011-014-518-522-57-011-014-518-321-2
Douglas fir-larch#16-910-513-216-118-86-79-812-214-1117-3
Douglas fir-larch#26-79-1012-615-317-96-39-211-714-216-5
Douglas fir-larch#35-27-79-711-813-64-97-08-1010-1012-6
Hem-firSS6-710-413-817-521-26-710-413-817-520-5
Hem-fir#16-510-213-015-1118-56-59-612-114-917-1
Hem-fir#26-29-712-214-1017-36-18-1111-313-915-11
Hem-fir#35-07-49-411-513-24-86-108-810-612-3
Southern pineSS6-1010-914-218-122-06-1010-914-218-121-10
Southern pine#16-710-413-515-918-86-79-1012-514-717-3
Southern pine#26-19-211-713-916-25-88-510-912-915-0
Southern pine#34-86-118-910-712-64-46-58-19-1011-7
Spruce-pine-firSS6-510-213-417-020-96-510-213-416-819-4
Spruce-pine-fir#16-49-912-415-117-66-29-011-513-1116-2
Spruce-pine-fir#26-49-912-415-117-66-29-011-513-1116-2
Spruce-pine-fir#35-07-49-411-513-24-86-108-810-612-3
19.2Douglas fir-larchSS6-710-413-717-420-116-710-413-716-819-4
Douglas fir-larch#16-49-612-014-817-16-08-1011-213-715-9
Douglas fir-larch#26-29-011-513-1116-25-88-410-712-1115-0
Douglas fir-larch#34-86-118-910-812-44-46-48-19-1011-5
Hem-firSS6-29-912-1016-519-116-29-912-1016-118-8
Hem-fir#16-19-511-1114-616-105-118-811-013-515-7
Hem-fir#25-98-911-113-715-95-78-110-312-714-7
Hem-fir#34-76-98-610-512-14-36-37-119-711-2
Southern pineSS6-510-213-417-020-96-510-213-416-1120-0
Southern pine#16-29-812-314-417-16-09-011-413-415-9
Southern pine#25-78-410-712-614-95-27-99-911-713-8
Southern pine#34-36-48-09-811-54-05-107-48-1110-7
Spruce-pine-firSS6-19-612-716-019-16-19-612-515-317-8
Spruce-pine-fir#15-118-1111-313-915-115-78-310-512-914-9
Spruce-pine-fir#25-118-1111-313-915-115-78-310-512-914-9
Spruce-pine-fir#34-76-98-610-512-14-36-37-119-711-2
24Douglas fir-larchSS6-19-712-716-118-86-19-712-214-1117-3
Douglas fir-larch#15-108-610-913-215-35-57-1010-012-214-1
Douglas fir-larch#25-68-110-312-614-65-17-69-511-713-5
Douglas fir-larch#34-36-27-109-611-13-115-87-38-1010-3
Hem-firSS5-99-111-1115-218-05-99-111-914-515-11
Hem-fir#15-88-510-813-015-15-47-99-1012-013-11
Hem-fir#25-47-109-1112-114-14-117-39-211-313-0
Hem-fir#34-16-07-79-410-93-105-77-18-710-0
Southern pineSS6-09-512-515-1019-36-09-512-515-217-10
Southern pine#15-98-811-012-1015-35-58-010-211-1114-1
Southern pine#25-07-59-511-313-24-76-118-910-512-3
Southern pine#33-105-87-18-810-33-65-36-78-09-6
Spruce-pine-firSS5-88-1011-814-817-15-88-1011-213-715-9
Spruce-pine-fir#15-57-1110-112-414-35-07-49-411-513-2
Spruce-pine-fir#25-57-1110-112-414-35-07-49-411-513-2
Spruce-pine-fir#34-16-07-79-410-93-105-77-18-710-0
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE R802.5.1(7)

RAFTER SPANS FOR 70 PSF GROUND SNOW LOAD (Ceiling not attached to rafters, L/Δ = 180)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum Rafter Spansa
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
(feet-
inches)
12Douglas fir-larchSS7-711-1015-819-922-107-711-1015-318-721-7
Douglas fir-larch#17-110-513-216-118-86-89-1012-515-217-7
Douglas fir-larch#26-99-1012-615-317-96-49-411-914-516-8
Douglas fir-larch#35-27-79-711-813-64-107-19-011-012-9
Hem-firSS7-211-314-918-1022-17-211-314-818-020-10
Hem-fir#17-010-313-015-1118-56-79-812-315-017-5
Hem-fir#26-79-712-214-1017-36-29-111-514-016-3
Hem-fir#35-07-49-411-513-24-96-118-910-912-5
Southern pineSS7-511-815-419-723-77-511-815-418-1022-3
Southern pine#17-110-713-515-918-86-910-012-814-1017-7
Southern pine#26-19-211-713-916-25-98-710-1112-1115-3
Southern pine#34-86-118-910-712-64-56-68-310-011-10
Spruce-pine-firSS7-011-014-618-020-117-011-013-1117-019-8
Spruce-pine-fir#16-89-912-415-117-66-39-211-814-216-6
Spruce-pine-fir#26-89-912-415-117-66-39-211-814-216-6
Spruce-pine-fir#35-07-49-411-513-24-96-118-910-912-5
16Douglas fir-larchSS6-1010-914-017-119-106-1010-513-216-118-8
Douglas fir-larch#16-29-011-513-1116-25-108-610-913-215-3
Douglas fir-larch#25-108-710-1013-315-45-68-110-312-614-6
Douglas fir-larch#34-66-68-310-111-94-36-27-109-611-1
Hem-firSS6-610-213-516-619-26-610-112-915-718-0
Hem-fir#16-18-1111-313-916-05-98-510-813-015-1
Hem-fir#25-88-410-612-1014-115-47-109-1112-114-1
Hem-fir#34-46-48-19-1011-54-16-07-79-410-9
Southern pineSS6-910-714-017-420-56-910-713-916-419-3
Southern pine#16-29-211-813-816-25-108-811-012-1015-3
Southern pine#25-37-1110-011-1114-05-07-59-511-313-2
Southern pine#34-16-07-79-210-103-105-87-18-810-3
Spruce-pine-firSS6-410-012-915-718-16-49-612-014-817-1
Spruce-pine-fir#15-98-510-813-115-25-57-1110-112-414-3
Spruce-pine-fir#25-98-510-813-115-25-57-1110-112-414-3
Spruce-pine-fir#34-46-48-19-1011-54-16-07-79-410-9
19.2Douglas fir-larchSS6-610-112-915-718-16-69-612-014-817-1
Douglas fir-larch#15-78-310-512-914-95-47-99-1012-013-11
Douglas fir-larch#25-47-109-1112-114-05-07-49-411-513-2
Douglas fir-larch#34-16-07-79-310-83-105-77-18-810-1
Hem-firSS6-19-712-415-117-46-19-211-814-215-5
Hem-fir#15-78-210-312-714-75-37-89-811-1013-9
Hem-fir#25-27-79-711-913-74-117-29-111-112-10
Hem-fir#34-05-107-49-010-53-95-66-118-69-10
Southern pineSS6-410-013-215-1018-86-49-1012-614-1117-7
Southern pine#15-88-510-812-514-95-47-1110-011-913-11
Southern pine#24-107-39-210-1012-94-66-108-810-312-1
Southern pine#33-85-66-118-49-113-65-26-67-119-4
Spruce-pine-firSS6-09-211-814-316-65-118-811-013-515-7
Spruce-pine-fir#15-37-89-911-1113-105-07-39-211-313-0
Spruce-pine-fir#25-37-89-911-1113-105-07-39-211-313-0
Spruce-pine-fir#34-05-107-49-010-53-95-66-118-69-10
24Douglas fir-larchSS6-09-011-513-1116-25-108-610-913-215-3
Douglas fir-larch#15-07-49-411-513-24-96-118-910-912-5
Douglas fir-larch#24-97-08-1010-1012-64-66-78-410-211-10
Douglas fir-larch#33-85-46-98-39-73-55-06-47-99-10
Hem-firSS5-88-811-013-613-115-78-310-512-412-4
Hem-fir#15-07-39-211-313-04-86-108-810-712-4
Hem-fir#24-86-98-710-612-24-46-58-19-1111-6
Hem-fir#33-75-26-78-19-43-44-116-37-78-10
Southern pineSS5-119-311-1114-216-85-118-1011-213-415-9
Southern pine#15-07-69-611-113-24-97-19-010-612-5
Southern pine#24-46-58-29-911-54-16-17-99-210-9
Southern pine#33-44-116-27-68-103-14-75-107-18-4
Spruce-pine-firSS5-68-310-512-914-95-47-99-1012-012-11
Spruce-pine-fir#14-86-118-910-812-44-56-68-310-011-8
Spruce-pine-fir#24-86-118-910-812-44-56-68-310-011-8
Spruce-pine-fir#33-75-26-78-19-43-44-116-37-78-10
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE R802.5.1(8)

RAFTER SPANS FOR 70 PSF GROUND SNOW LOAD (Ceiling attached to rafters, L/Δ = 240)

RAFTER
SPACING
(inches)
SPECIES AND GRADEDEAD LOAD = 10 psfDEAD LOAD = 20 psf
2 × 42 × 62 × 82 × 102 × 122 × 42 × 62 × 82 × 102 × 12
Maximum rafter spansa
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
(feet -
inches)
12Douglas fir-larchSS6-1010-914-318-222-16-1010-914-318-221-7
Douglas fir-larch#16-710-513-216-118-86-79-1012-515-217-7
Douglas fir-larch#26-69-1012-615-317-96-49-411-914-516-8
Douglas fir-larch#35-27-79-711-813-64-107-19-011-012-9
Hem-firSS6-610-213-517-220-106-610-213-517-220-10
Hem-fir#16-410-013-015-1118-56-49-812-315-017-5
Hem-fir#26-19-612-214-1017-36-19-111-514-016-3
Hem-fir#35-07-49-411-513-24-96-118-910-912-5
Southern pineSS6-910-714-017-1021-86-910-714-017-1021-8
Southern pine#16-610-213-515-918-86-610-012-814-1017-7
Southern pine#26-19-211-713-916-25-98-710-1112-1115-3
Southern pine#34-86-118-910-712-64-56-68-310-011-10
Spruce-pine-firSS6-410-013-216-920-56-410-013-216-919-8
Spruce-pine-fir#16-29-912-415-117-66-29-211-814-216-6
Spruce-pine-fir#26-29-912-415-117-66-29-211-814-216-6
Spruce-pine-fir#35-07-49-411-513-24-96-118-910-912-5
16Douglas fir-larchSS6-39-1012-1116-619-106-39-1012-1116-118-8
Douglas fir-larch#16-09-011-513-1116-25-108-610-913-215-3
Douglas fir-larch#25-108-710-1013-315-45-68-110-312-614-6
Douglas fir-larch#34-66-68-310-111-94-36-27-109-611-1
Hem-firSS5-119-312-215-718-115-119-312-215-718-0
Hem-fir#15-98-1111-313-916-05-98-510-813-015-1
Hem-fir#25-68-410-612-1014-115-47-109-1112-114-1
Hem-fir#34-46-48-19-1011-54-16-07-79-410-9
Southern pineSS6-19-712-816-219-86-19-712-816-219-3
Southern pine#15-119-211-813-816-25-108-811-012-1015-3
Southern pine#25-37-1110-011-1114-05-07-59-511-313-2
Southern pine#34-16-07-79-210-103-105-87-18-810-3
Spruce-pine-firSS5-99-111-1115-318-15-99-111-1114-817-1
Spruce-pine-fir#15-88-510-813-115-25-57-1110-112-414-3
Spruce-pine-fir#25-88-510-813-115-25-57-1110-112-414-3
Spruce-pine-fir#34-46-48-19-1011-54-16-07-79-410-9
19.2Douglas fir-larchSS5-109-312-215-618-15-109-312-014-817-1
Douglas fir-larch#15-78-310-512-914-95-47-99-1012-013-11
Douglas fir-larch#25-47-109-1112-114-05-07-49-411-513-2
Douglas fir-larch#34-16-07-79-310-83-105-77-18-810-1
Hem-firSS5-68-811-614-817-45-68-811-614-215-5
Hem-fir#15-58-210-312-714-75-37-89-811-1013-9
Hem-fir#25-27-79-711-913-74-117-29-111-112-10
Hem-fir#34-05-107-49-010-53-95-66-118-69-10
Southern pineSS5-99-111-1115-318-65-99-111-1114-1117-7
Southern pine#15-68-510-812-514-95-47-1110-011-913-11
Southern pine#24-107-39-210-1012-94-66-108-810-312-1
Southern pine#33-85-66-118-49-113-65-26-67-119-4
Spruce-pine-firSS5-58-611-314-316-65-58-611-013-515-7
Spruce-pine-fir#15-37-89-911-1113-105-07-39-211-313-0
Spruce-pine-fir#25-37-89-911-1113-105-07-39-211-313-0
Spruce-pine-fir#34-05-107-49-010-53-95-66-118-69-10
24Douglas fir-larchSS5-58-711-313-1116-25-58-610-913-215-3
Douglas fir-larch#15-07-49-411-513-24-96-118-910-912-5
Douglas fir-larch#24-97-08-1010-1012-64-66-78-410-211-10
Douglas fir-larch#33-85-46-98-39-73-55-06-47-99-0
Hem-firSS5-28-110-813-613-115-28-110-512-412-4
Hem-fir#15-07-39-211-313-04-86-108-810-712-4
Hem-fir#24-86-98-710-612-24-46-58-19-1111-6
Hem-fir#33-75-26-78-19-43-44-116-37-78-10
Southern pineSS5-48-511-114-216-85-48-511-113-415-9
Southern pine#15-07-69-611-113-24-97-19-010-612-5
Southern pine#24-46-58-29-911-54-16-17-99-210-9
Southern pine#33-44-116-27-68-103-14-75-107-18-4
Spruce-pine-firSS5-07-1110-512-914-95-07-99-1012-012-11
Spruce-pine-fir#14-86-118-910-812-44-56-68-310-011-8
Spruce-pine-fir#24-86-118-910-812-44-56-68-310-011-8
Spruce-pine-fir#33-75-26-78-19-43-44-116-37-78-10
Check sources for availability of lumber in lengths greater than 20 feet.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls, such as rafter ties, is provided at that location. Where ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the following factors:

    HC/HRRafter Span Adjustment Factor
    1/30.67
    1/40.76
    1/50.83
    1/60.90
    1/7.5 or less1.00

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

TABLE R802.5.1(9)

RAFTER/CEILING JOIST HEEL JOINT CONNECTIONSa, b, c, d, e, f, h

RAFTER RAFTER
SPACING
(inches)
GROUND SNOW LOAD (psf)
20g305070
Roof span (feet)
12202836122028361220283612202836
Required number of 16d common nailsa, b per heel joint splicesc, d, e, f
3:121246810468115812156111520
1658101358111461115208142026
2471115197111621916233012213039
4:12123568356846911581215
1646810468115812156111520
2458121559121671217229162329
5:121234563457357947912
163568357947912591216
244791247101361014187131823
7:12123445334534573579
1634563456357946911
2435793579471013591317
9:12123344333433453457
163445334534573579
243467346736810471013
12:12123333333333343345
163344333433453457
2434453346346836810

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. 40d box nails shall be permitted to be substituted for 16d common nails.
  2. Nailing requirements shall be permitted to be reduced 25 percent if nails are clinched.
  3. Heel joint connections are not required where the ridge is supported by a load-bearing wall, header or ridge beam.
  4. Where intermediate support of the rafter is provided by vertical struts or purlins to a load-bearing wall, the tabulated heel joint connection requirements shall be permitted to be reduced proportionally to the reduction in span.
  5. Equivalent nailing patterns are required for ceiling joist to ceiling joist lap splices.
  6. Where rafter ties are substituted for ceiling joists, the heel joint connection requirement shall be taken as the tabulated heel joint connection requirement for two-thirds of the actual rafter slope.
  7. Applies to roof live load of 20 psf or less.
  8. Tabulated heel joint connection requirements assume that ceiling joists or rafter ties are located at the bottom of the attic space. Where ceiling joists or rafter ties are located higher in the attic, heel joint connection requirements shall be increased by the following factors:

    HC/HRHeel Joint Connection Adjustment Factor
    1/31.5
    1/41.33
    1/51.25
    1/61.2
    1/10 or less1.11

    where:

    HC = Height of ceiling joists or rafter ties measured vertically above the top of the rafter support walls.

    HR= Height of roof ridge measured vertically above the top of the rafter support walls.

For SI: 1 inch = 25.4 mm, 1 foot = 305 mm, 1 degree = 0.018 rad.

Note: Where ceiling joists run perpendicular to the rafter, rafter ties shall be installed in accordance with Section R802.3.1.

HC = Height of ceiling joists or rafter ties measured vertically above the top of rafter support walls.

HR = Height of roof ridge measured vertically above the top of the rafter support walls.

FIGURE R802.5.1

BRACED RAFTER CONSTRUCTION

The ends of each rafter or ceiling joist shall have not less than 11/2 inches (38 mm) of bearing on wood or metal and not less than 3 inches (76 mm) on masonry or concrete. The bearing on masonry or concrete shall be direct, or a sill plate of 2-inch (51 mm) minimum nominal thickness shall be provided under the rafter or ceiling joist. The sill plate shall provide a minimum nominal bearing area of 48 square inches (30 865 mm2).
If the finished ceiling material is installed on the ceiling prior to the attachment of the ceiling to the walls, such as in construction at a factory, a compression strip of the same thickness as the finished ceiling material shall be installed directly above the top plate of bearing walls if the compressive strength of the finished ceiling material is less than the loads it will be required to withstand. The compression strip shall cover the entire length of such top plate and shall be not less than one-half the width of the top plate. It shall be of material capable of transmitting the loads transferred through it.
Structural roof members shall not be cut, bored or notched in excess of the limitations specified in this section.
Cuts, notches and holes in solid lumber joists, rafters, blocking and beams shall comply with the provisions of Section R502.8.1 except that cantilevered portions of rafters shall be permitted in accordance with Section R802.7.1.1.

Notches on cantilevered portions of rafters are permitted provided the dimension of the remaining portion of the rafter is not less than 31/2 inches (89 mm) and the length of the cantilever does not exceed 24 inches (610 mm) in accordance with Figure R802.7.1.1.

For SI: 1 inch = 25.4 mm.

FIGURE R802.7.1.1

RAFTER NOTCH

Taper cuts at the ends of the ceiling joist shall not exceed one-fourth the depth of the member in accordance with Figure R802.7.1.2.

FIGURE R802.7.1.2

CEILING JOIST TAPER CUT

Cuts, notches and holes bored in trusses, structural composite lumber, structural glue-laminated members, cross-laminated timber members or I-joists are prohibited 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.

Roof framing members and ceiling joists having a depth-to-thickness ratio exceeding 5 to 1 based on nominal dimensions shall be provided with lateral support at points of bearing to prevent rotation. For roof rafters with ceiling joists attached in accordance with Table R602.3(1), the depth-to-thickness ratio for the total assembly shall be determined using the combined thickness of the rafter plus the attached ceiling joist.

Exception: Roof trusses shall be braced in accordance with Section R802.10.3.

Rafters and ceiling joists having a depth-to-thickness ratio exceeding 6 to 1 based on nominal dimensions shall be supported laterally by solid blocking, diagonal bridging (wood or metal) or a continuous 1-inch by 3-inch (25 mm by 76 mm) wood strip nailed across the rafters or ceiling joists at intervals not exceeding 8 feet (2438 mm).
Openings in roof and ceiling framing shall be framed with header and trimmer joists. Where the header joist span does not exceed 4 feet (1219 mm), the header joist shall be permitted to be a single member the same size as the ceiling joist or rafter. Single trimmer joists shall be permitted to be used to carry a single header joist that is located within 3 feet (914 mm) of the trimmer joist bearing. Where the header joist span exceeds 4 feet (1219 mm), the trimmer joists and the header joist shall be doubled and of sufficient cross section to support the ceiling joists or rafter framing into the header. Approved hangers shall be used for the header joist to trimmer joist connections where the header joist span exceeds 6 feet (1829 mm). Tail joists over 12 feet (3658 mm) long 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).

Truss design drawings, prepared in conformance to Section R802.10.1, shall be provided to the building official and approved 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:

  1. Slope or depth, span and spacing.
  2. Location of all joints.
  3. Required bearing widths.
  4. Design loads as applicable.

    1. 4.1. Top chord live load (as determined from Section R301.6).
    2. 4.2. Top chord dead load.
    3. 4.3. Bottom chord live load.
    4. 4.4. Bottom chord dead load.
    5. 4.5. Concentrated loads and their points of application.
    6. 4.6. Controlling wind and earthquake loads.
  5. Adjustments to lumber and joint connector design values for conditions of use.
  6. Each reaction force and direction.
  7. Joint connector type and description such as size, thickness or gage and the dimensioned location of each joint connector except where symmetrically located relative to the joint interface.
  8. Lumber size, species and grade for each member.
  9. Connection requirements for:

    1. 9.1. Truss to girder-truss.
    2. 9.2. Truss ply to ply.
    3. 9.3. Field splices.
  10. Calculated deflection ratio and/or maximum description for live and total load.
  11. Maximum axial compression forces in the truss members to enable the building designer to design the size, connections and anchorage of the permanent continuous lateral bracing. Forces shall be shown on the truss design drawing or on supplemental documents.
  12. Required permanent truss member bracing location.
Wood trusses shall be designed in accordance with accepted engineering practice. The design and manufacture of metal-plate-connected wood trusses shall comply with ANSI/TPI 1. The truss design drawings shall be prepared by a registered professional where required by the Florida Statutes.
The provisions of this section shall control the design of truss roof framing when snow controls for buildings, not greater than 60 feet (18 288 mm) in length perpendicular to the joist, rafter or truss span, not greater than 36 feet (10 973 mm) in width parallel to the joist, rafter or truss span, not more than three stories above grade plane in height, and roof slopes not smaller than 3:12 (25 percent slope) or greater than 12:12 (100-percent slope). Truss roof framing constructed in accordance with the provisions of this section shall be limited to sites subjected to a maximum design wind speed of 140 miles per hour (63 m/ s), Exposure B or C, and a maximum ground snow load of 70 psf (3352 Pa). For consistent loading of all truss types, roof snow load is to be computed as: 0.7 pg.
Trusses shall be braced to prevent rotation and provide lateral stability in accordance with the requirements specified in the construction documents for the building and on the individual truss design drawings. In the absence of specific bracing requirements, trusses shall be braced in accordance with accepted industry practice such as the SBCA Building Component Safety Information (BCSI) Guide to Good Practice for Handling, Installing & Bracing of Metal Plate Connected Wood Trusses.
Truss members shall not be cut, notched, drilled, spliced or otherwise altered in any way without the approval of a registered design professional. Alterations resulting in the addition of load such as HVAC equipment water heater that exceeds the design load for the truss shall not be permitted without verification that the truss is capable of supporting such additional loading.

TABLE R802.11

RAFTER OR TRUSS UPLIFT CONNECTION FORCES FROM WIND (ASD) (POUNDS PER CONNECTION)a, b, c, d, e, f, g, h

RAFTER
OR TRUSS
SPACING
ROOF
SPAN
(feet)
EXPOSURE B
Ultimate Design Wind Speed VULT (mph)
110115120130140
Roof PitchRoof PitchRoof PitchRoof PitchRoof Pitch
< 5:12≥ 5:12< 5:12≥ 5:12< 5:12≥ 5:12< 5:12≥ 5:12< 5:12≥ 5:12
12″ o.c.124843595370649588122113
18595274668981122112157146
247162897910898149137192178
2879699988121109167153216200
32867510997134120185170240222
369482120106146132203186264244
4210692135120166149230211300278
48118102151134185166258236336311
16″ o.c.12645778709385126117162150
1878699888118108162149209194
249482118105144130198182255237
2810592132117161145222203287266
32114100145129178160246226319295
36125109160141194176270247351325
42141122180160221198306281399370
48157136201178246221343314447414
24″ o.c.129686118106140128190176244226
18118104148132178162244224314292
24142124178158216196298274384356
28158138198176242218334306432400
32172150218194268240370340480444
36188164240212292264406372528488
42212184270240332298460422600556
48236204302268370332516472672622
12″ o.c.129588110102126118161151198186
18121111141131163151208195257242
24148136173160200185256239317298
28166152195179225208289269358335
32184168216199249231321299398373
36202185237219274254353329438411
42229210269248312289402375499468
48256234302278349323450420560524
16″ o.c.12126117146136168157214201263247
18161148188174217201277259342322
24197181230213266246340318422396
28221202259238299277384358476446
32245223287265331307427398529496
36269246315291364338469438583547
42305279358330415384535499664622
48340311402370464430599559745697
24″ o.c.12190176220204252236322302396372
18242222282262326302416390514484
24296272346320400370512478634596
28332304390358450416578538716670
32368336432398498462642598796746
36404370474438548508706658876822
42458420538496624578804750998936
4851246860455669864690084011201048

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound = 0.454 kg, 1 pound per square foot = 47.9 N/m2, 1 plf = 14.6 N/m.

  1. The uplift connection forces are based on a maximum 33-foot mean roof height and Wind Exposure Category B or C. For Exposure D, the uplift connection force shall be selected from the Exposure C portion of the table using the next highest tabulated ultimate design wind speed. The adjustment coefficients in Table R301.2(3) shall not be used to multiply the tabulated forces for Exposures C and D or for other mean roof heights.
  2. The uplift connection forces include an allowance for roof and ceiling assembly dead load of 15 psf.
  3. The tabulated uplift connection forces are limited to a maximum roof overhang of 24 inches.
  4. The tabulated uplift connection forces shall be permitted to be multiplied by 0.75 for connections not located within 8 feet of building corners.
  5. For buildings with hip roofs with 5:12 and greater pitch, the tabulated uplift connection forces shall be permitted to be multiplied by 0.70. This reduction shall not be combined with any other reduction in tabulated forces.
  6. For wall-to-wall and wall-to-foundation connections, the uplift connection force shall be permitted to be reduced by 60 plf for each full wall above.
  7. Linear interpolation between tabulated roof spans and wind speeds shall be permitted.
  8. The tabulated forces for a 12-inch on-center spacing shall be permitted to be used to determine the uplift load in pounds per linear foot.

Roof assemblies shall have uplift resistance in accordance with Sections R802.11.1.1 and R802.11.1.2.

Where the uplift force does not exceed 200 pounds (90.8 kg), rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1).

Where the basic wind speed does not exceed 115 mph, the wind exposure category is B, the roof pitch is 5:12 or greater, and the roof span is 32 feet (9754 mm) or less, rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1).

Trusses shall be attached to supporting wall assemblies by connections capable of resisting uplift forces as specified on the truss design drawings for the ultimate design wind speed as determined by Figure R301.2(4) and listed in Table R301.2(1) or as shown on the construction documents. Uplift forces shall be permitted to be determined as specified by Table R802.11, if applicable, or as determined by accepted engineering practice.
Individual rafters shall be attached to supporting wall assemblies by connections capable of resisting uplift forces as determined by Table R802.11 or as determined by accepted engineering practice. Connections for beams used in a roof system shall be designed in accordance with accepted engineering practice.

Allowable spans for lumber used as roof sheathing shall conform to Table R803.1. Spaced lumber sheathing for wood shingle and shake roofing shall conform to the requirements of Sections R905.7 and R905.8. Spaced lumber sheathing is not allowed in Seismic Design Category D2.

TABLE R803.1

MINIMUM THICKNESS OF LUMBER ROOF SHEATHING

RAFTER OR BEAM SPACING
(inches)
MINIMUM NET THICKNESS
(inches)
245/8
48a11/2 T & G
60b
72c

For SI: 1 inch = 25.4 mm.

  1. Minimum 270 Fb, 340,000 E.
  2. Minimum 420 Fb, 660,000 E.
  3. Minimum 600Fb, 1,150,000 E.
Wood structural panels shall conform to DOC PS 1, DOC PS 2, CSA O437 or CSA O325, and shall be identified for grade, bond classification and performance category by a grade mark or certificate of inspection issued by an approved agency. Wood structural panels shall comply with the grades specified in Table R503.2.1.1(1).
Wood structural panels, when designed to be permanently exposed in outdoor applications, shall be of an exterior exposure durability. Wood structural panel roof sheathing exposed to the underside shall be permitted to be of interior type bonded with exterior glue, identified as Exposure 1.
The allowable unit stresses for fire-retardant-treated plywood, 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 plywood will be subjected, the type of treatment and redrying process. The fire-retardant-treated plywood shall be graded by an approved agency.
The maximum allowable spans for wood structural panel roof sheathing shall not exceed the values set forth in Table R503.2.1.1(1), or APA E30.
Wood structural panel used as roof sheathing shall be installed with joints staggered in accordance with Section R803.2.3.1 for wood roof framing or with Table R804.3 for cold-formed steel roof framing.

Wood structural panel sheathing shall be fastened to roof framing with RSRS-01 (2 3/8" × 0.113") nails at 6 inches (152 mm) on center at edges and 6 inches (152 mm) on center at intermediate framing, unless roof diaphragm design requires a closer spacing. RSRS-01 is ring shank roof sheathing nail meeting the specifications in ASTM F1667.

Where roof framing with a specific gravity, 0.42 ≤ G < 0.49 is used, spacing of ring-shank fasteners shall be 4 inches on center in nailing zone 3 in accordance with Figure R803.2.3.1 where Vult is 165 mph or greater.

Exceptions:

  1. Where roof framing with a specific gravity, 0.42 ≤ G < 0.49 is used, spacing of ring-shank fasteners shall be permitted at 12 inches (305 mm) on center at intermediate framing in nailing zone 1 for any Vult and in nailing zone 2 for Vult less than or equal to 140 mph in accordance with Figure R803.2.3.1.
  2. Where roof framing with a specific gravity, G = 0.49 is used, spacing of ring-shank fasteners shall be permitted at 12 inches (305 mm) on center at intermediate framing in nailing zone 1 for any Vult and in nailing zone 2 for Vult less than or equal to 150 mph in accordance with Figure R803.2.3.1.
  3. Where roof framing with a specific gravity, G = 0.49 is used, 8d common or 8d hot-dipped galvanized box nails at 6 inches (152 mm) on center at edges and 6 inches (152 mm) on center at intermediate framing shall be permitted for Vult less than or equal to 130 mph in accordance with Figure R803.2.3.1.

For SI: 1 inch = 25.4 mm.

FIGURE R803.2.3.1

ROOF SHEATHING NAILING ZONES

Elements shall be straight and free of any defects that would significantly affect their structural performance. Cold-formed steel roof framing members shall be in accordance with the requirements of this section.
The provisions of this section shall control the construction of cold-formed steel roof framing for buildings not greater than 60 feet (18 288 mm) perpendicular to the joist, rafter or truss span, not greater than 40 feet (12 192 mm) in width parallel to the joist span or truss, less than or equal to three stories above grade plane and with roof slopes not less than 3:12 (25- percent slope) or greater than 12:12 (100-percent slope). Cold-formed steel roof framing constructed in accordance with the provisions of this section shall be limited to sites where the ultimate design wind speed is less than 139 miles per hour (62 m/s), Exposure Category B or C, and the ground snow load is less than or equal to 70 pounds per square foot (3350 Pa).

Cold-formed steel roof framing constructed in accordance with Section R804 shall be located in line with load-bearing studs in accordance with Figure R804.1.2 and the tolerances specified as follows:

  1. The maximum tolerance shall be 3/4 inch (19.1 mm) between the centerline of the horizontal framing member and the centerline of the vertical framing member.
  2. Where the centerline of the horizontal framing member and bearing stiffener are located to one side of the centerline of the vertical framing member, the maximum tolerance shall be 1/8 inch (3.2 mm) between the web of the horizontal framing member and the edge of the vertical framing member.

For SI: 1 inch = 25.4 mm.

FIGURE R804.1.2

IN-LINE FRAMING

Load-bearing, cold-formed steel roof framing members shall be in accordance with this section.
Load-bearing, cold-formed steel framing members shall be cold formed to shape from structural quality sheet steel complying with the requirements of ASTM A1003, Structural Grades 33 Type H and 50 Type H.

Load-bearing, coldformed steel framing shall have a metallic coating complying with ASTM A1003 and one of the following:

  1. A minimum of G 60 in accordance with ASTM A653.
  2. A minimum of AZ 50 in accordance with ASTM A792.

Load-bearing, cold-formed steel roof framing members shall comply with Figure R804.2.3(1) and with the dimensional and thickness requirements specified in Table R804.2.3. Additionally, C-shaped sections shall have a minimum flange width of 1.625 inches (41 mm) and a maximum flange width of 2 inches (51 mm). The minimum lip size for C-shaped sections shall be 1/2 inch (12.7 mm). Tracks shall comply with Figure R804.2.3(2) and shall have a minimum flange width of 11/4 inches (32 mm). Minimum Grade 33 ksi steel shall be used wherever 33 mil and 43 mil thicknesses are specified. Minimum Grade 50 ksi steel shall be used wherever 54 and 68 mil thicknesses are specified.

TABLE R804.2.3

LOAD-BEARING COLD-FORMED STEEL ROOF FRAMING MEMBER SIZES AND THICKNESSES

MEMBER
DESIGNATIONa
WEB DEPTH
(inches)
MINIMUM BASE STEEL THICKNESS
mil (inches)
350S162-t3.533 (0.0329), 43 (0.0428), 54 (0.0538)
550S162-t5.533 (0.0329), 43 (0.0428), 54 (0.0538), 68 (0.0677)
800S162-t833 (0.0329), 43 (0.0428), 54 (0.0538), 68 (0.0677)
1000S162-t1043 (0.0428), 54 (0.0538), 68 (0.0677)
1200S162-t1243 (0.0428), 54 (0.0538), 68 (0.0677)

For SI: 1 inch = 25.4 mm

  1. The member designation is defined by the first number representing the member depth in hundredths of an inch, the letter “s” representing a stud or joist member, the second number representing the flange width in hundredths of an inch and the letter “t” shall be a number representing the minimum base metal thickness in mils.

FIGURE R804.2.3(1)

C-SHAPED SECTION

FIGURE R804.2.3(2)

TRACK SECTION

Load-bearing, cold-formed steel framing members shall have a legible label, stencil, stamp or embossment with the following information as a minimum:

  1. Manufacturer’s identification.
  2. Minimum base steel thickness in inches (mm).
  3. Minimum coating designation.
  4. Minimum yield strength, in kips per square inch (ksi) (MPa).
Screws for steel-tosteel connections shall be installed with a minimum edge distance and center-to-center spacing of 1/2 inch (12.7 mm), shall be self-drilling tapping and shall conform to ASTM C1513. Structural sheathing shall be attached to cold-formed steel roof rafters with minimum No. 8 selfdrilling tapping screws that conform to ASTM C1513. Screws for attaching structural sheathing to cold-formed steel roof framing shall have a minimum head diameter of 0.292 inch (7.4 mm) with countersunk heads and shall be installed with a minimum edge distance of 3/8 inch (9.5 mm). Gypsum board ceilings shall be attached to coldformed steel joists with minimum No. 6 screws conforming to ASTM C954 or ASTM C1513 with a bugle-head style and shall be installed in accordance with Section R805. For all connections, screws shall extend through the steel a minimum of three exposed threads. Fasteners shall have rust-inhibitive coating suitable for the installation in which they are being used, or be manufactured from material not susceptible to corrosion.
Web holes, web hole reinforcing and web hole patching shall be in accordance with this section.

Web holes in roof framing members shall comply with all of the following conditions:

  1. Holes shall conform to Figure R804.2.6.1.
  2. Holes shall be permitted only along the centerline of the web of the framing member.
  3. Center-to-center spacing of holes shall not be less than 24 inches (610 mm).
  4. The web hole width shall be not greater than onehalf the member depth, or 21/2 inches (64 mm).
  5. Holes shall have a web hole length not exceeding 41/2 inches (114 mm).
  6. The minimum distance between the edge of the bearing surface and the edge of the web hole shall be not less than 10 inches (254 mm).

Framing members with web holes not conforming to Items 1 though 6 shall be reinforced in accordance with Section R804.2.6.2, patched in accordance with Section R804.2.6.3 or designed in accordance with accepted engineering practices.

For SI: 1 inch = 25.4 mm.

FIGURE R804.2.6.1

ROOF FRAMING MEMBER WEB HOLES

Reinforcement of web holes in ceiling joists not conforming to the requirements of Section R804.2.6.1 shall be permitted if the hole is located fully within the center 40 percent of the span and the depth and length of the hole do not exceed 65 percent of the flat width of the web. The reinforcing shall be a steel plate or C-shaped section with a hole that does not exceed the web hole size limitations of Section R804.2.6.1 for the member being reinforced. The steel reinforcing shall be the same thickness as the receiving member and shall extend not less than 1 inch (25 mm) beyond all edges of the hole. The steel reinforcing shall be fastened to the web of the receiving member with No. 8 screws spaced not greater than 1 inch (25 mm) center to center along the edges of the patch with minimum edge distance of 1/2 inch (12.7 mm).

Patching of web holes in roof framing members not conforming to the requirements in Section R804.2.6.1 shall be permitted in accordance with either of the following methods:

  1. Framing members shall be replaced or designed in accordance with accepted engineering practices where web holes exceed either of the following size limits:

    1. 1.1. The depth of the hole, measured across the web, exceeds 70 percent of the flat width of the web.
    2. 1.2. The length of the hole measured along the web, exceeds 10 inches (254 mm) or the depth of the web, whichever is greater.
  2. Web holes not exceeding the dimensional requirements in Section R804.2.6.3, Item 1, shall be patched with a solid steel plate, stud section or track section in accordance with Figure R804.2.6.3. The steel patch shall, as a minimum, be the same thickness as the receiving member and shall extend not less than 1 inch (25 mm) beyond all edges of the hole. The steel patch shall be fastened to the web of the receiving member with No. 8 screws spaced not greater than 1 inch (25 mm) center-to-center along the edges of the patch with minimum edge distance of 1/2 inch (12.7 mm).

For SI: 1 inch = 25.4 mm.

FIGURE R804.2.6.3

ROOF FRAMING MEMBER WEB HOLE PATCH

Cold-formed steel roof systems constructed in accordance with the provisions of this section shall consist of both ceiling joists and rafters in accordance with Figure R804.3 and fastened in accordance with Table R804.3.

TABLE R804.3

ROOF FRAMING FASTENING SCHEDULEa, b

DESCRIPTION OF BUILDING ELEMENTSNUMBER AND SIZE OF FASTENERSaSPACING OF FASTENERS
Roof sheathing (oriented strand board or plywood)
  to rafter
No. 8 screws6″ o.c. on edges and 12″
o.c. at interior supports. 6″
o.c. at gable end truss
Gable end truss to end wall top trackNo. 10 screws12″ o.c.
Rafter to ceiling joistMinimum No. 10 screws, in accordance with Evenly spaced, not less
than 1/2″ from all edges.
Ceiling joist or
roof truss to top
track of bearing
wallb
Ceiling Joist
Spacing (in.)
Roof Span (ft)Ultimate Design Wind Speed
(mph) and Exposure Category
Each ceiling joist
or roof truss
126 B
110 C
<139B
115C
126 C<139C
16242223
282233
322234
362234
402234
24242234
282245
322345
362346
402356

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mil = 0.0254 mm.

  1. Screws are a minimum No. 10 unless noted otherwise.
  2. Indicated number of screws shall be applied through the flanges of the truss or ceiling joist or through each leg of a 54 mil clip angle. See Section R804.3.8 for additional requirements to resist uplift forces.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

FIGURE R804.3

COLD-FORMED STEEL ROOF CONSTRUCTION

Cold-formed steel ceiling joists shall be in accordance with this section.

Ceiling joist size and thickness shall be determined in accordance with the limits set forth in Tables R804.3.1.1(1) and R804.3.1.1(2). When determining the size of ceiling joists, the lateral support of the top flange shall be classified as unbraced, braced at midspan or braced at third points in accordance with Section R804.3.1.3. Where sheathing material is attached to the top flange of ceiling joists or where the bracing is spaced closer than third point of the joists, the “third point” values from Tables R804.3.1.1(1) and R804.3.1.1(2) shall be used.

Ceiling joists shall have a bearing support length of not less than 11/2 inches (38 mm) and shall be connected to roof rafters (heel joint) with No. 10 screws in accordance with Figure R804.3.1.1 and Table 804.3.1.1(3).

Where continuous joists are framed across interior bearing supports, the interior bearing supports shall be located within 24 inches (610 mm) of midspan of the ceiling joist, and the individual spans shall not exceed the applicable spans in Tables R804.3.1.1(1) and R804.3.1.1(2).

Where the attic is to be used as an occupied space, the ceiling joists shall be designed in accordance with Section R505.

TABLE R804.3.1.1(1)

CEILING JOIST SPANS 10 PSF LIVE LOAD (NO ATTIC STORAGE)a, b, c

MEMBER
DESIGNATION
ALLOWABLE SPAN (feet - inches)
Lateral Support of Top (Compression) Flange
UnbracedMidspan BracingThird-point Bracing
Ceiling Joist Spacing (inches)
162416241624
350S162-339'-5″8'-6″12'-2″10'-4″12'-2″10'-7″
350S162-4310'-3″9'-12″13'-2″11'-6″13'-2″11'-6″
350S162-5411'-1″9'-11″13'-9″12'-0″13'-9″12'-0″
350S162-6812'-1″10'-9″14'-8″12'-10″14'-8″12'-10″
550S162-3310'-7″9'-6″14'-10″12'-10″15'-11″13'-4″
550S162-4311'-8″10'-6″16'-4″14'-3″17'-10″15'-3″
550S162-5412'-6″11'-2″17'-7″15'-7″19'-5″16'-10″
550S162-6813'-6″12'-1″19'-2″17'-0″21'-0″18'-4″
800S162-33
800S162-4313'-0″11'-9″18'-10″17'-0″21'-6″19'-0″
800S162-5413'-10″12'-5″20'-0″18'-0″22'-9″20'-4″
800S162-6814'-11″13'-4″21'-3″19'-1″24'-1″21'-8″
1000S162-43
1000S162-5414'-9″13'-3″21'-4″19'-3″24'-4″22'-0″
1000S162-6815'-10″14'-2″22'-8″20'-5″25'-9″23'-2″
1200S162-43
1200S162-54
1200S162-6816'-8″14'-11″23'-11″21'-6″27'-2″24'-6″

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa.

  1. Deflection criterion: L/240 for total loads.
  2. Ceiling dead load = 5 psf.
  3. Minimum Grade 33 ksi steel shall be used for 33 mil and 43 mil thicknesses. Minimum Grade 50 ksi steel shall be used for 54 and 68 mil thicknesses.

TABLE R804.3.1.1(2)

CEILING JOIST SPANS 20 PSF LIVE LOAD (LIMITED ATTIC STORAGE)a, b, c

MEMBER
DESIGNATION
ALLOWABLE SPAN (feet - inches)
Lateral Support of Top (Compression) Flange
UnbracedMidspan BracingThird-point Bracing
Ceiling Joist Spacing (inches)
162416241624
350S162-338'-2″6'-10″9'-9″6'-10″9'-11″6'-10″
350S162-438'-10″7'-10″11'-0″9'-5″11'-0″9'-7″
350S162-549'-6″8'-6″11'-9″10'-3″11'-9″10'-3″
350S162-6810'-4″9'-2″12'-7″11'-0″12'-7″11'-0″
550S162-339'-2″8'-3″12'-2″8'-5″12'-6″8'-5″
550S162-4310'-1″9'-1″13'-7″11'-8″14'-5″12'-2″
550S162-5410'-9″9'-8″14'-10″12'-10″15'-11″13'-6″
550S162-6811'-7″10'-4″16'-4″14'-0″17'-5″14'-11″
800S162-33
800S162-4311'-4″10'-1″16'-5″13'-6″18'-1″13'-6″
800S162-5420'-0″10'-9″17'-4″15'-6″19'-6″27'-0″
800S162-6812'-10″11'-6″18'-5″16'-6″20'-10″18'-3″
1000S162-43
1000S162-5412'-10″11'-6″18'-7″16'-9″21'-2″15'-5″
1000S162-6813'-8″12'-3″19'-8″17'-8″22'-4″20'-1″
1200S162-43
1200S162-54
1200S162-68