CODES

ADOPTS WITH AMENDMENTS:

International Residential Code 2012 (IRC 2012)

Copyright

Preface

Chapter 1 Administration

Part II ‒ Definitions

Chapter 2 Definitions

Part III ‒ Building Planning and Construction

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

Part IV ‒ Energy Conservation

Chapter 11 [RE] Energy Efficiency

Part V ‒ Mechanical

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 Energy Systems

Part VI ‒ Fuel Gas

Chapter 24 Fuel Gas

Part VII ‒ Plumbing

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

Part VIII ‒ Electrical

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

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

Part IX ‒ Referenced Standards

Chapter 44 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 Manufactured Housing Used as Dwellings

Appendix F Radon Control Methods

Appendix H Patio Covers

Appendix K Sound Transmission

Appendix N Venting Methods

Appendix P Sizing of Water Piping System

Appendix Q Icc International Residential Code Electrical Provisions/ National Electrical Code Cross Reference

The provisions of this chapter shall control the design and construction of the roof-ceiling system for all buildings.
Roof and ceiling construction shall be capable of accommodating all loads imposed according to 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 at least 5 feet (1524 mm) from foundation walls or to an approved drainage system.

Load-bearing dimension lumber for rafters, trusses and ceiling joists shall be identified by a grade mark of a lumber grading or inspection agency that has been approved 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.
Blocking shall be a minimum of utility grade lumber.
Approved end-jointed lumber identified by a grade mark conforming to Section R802.1 may 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.
Fire-retardant-treated wood (FRTW) is any wood product which, when impregnated with chemicals by a pressure process or other means during manufacture, shall have, when tested in accordance with ASTM E 84 or UL 723, a listed flame spread index of 25 or less and shows no evidence of significant progressive combustion when 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 R802.1.3. 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 International Building Code.
  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 R802.1.3.5 through R802.1.3.8.
  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 D 2898).
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 which 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 D 5516. The test data developed by ASTM D 5516 shall be used to develop adjustment factors, maximum loads and spans, or both for untreated plywood design values in accordance with ASTM D 6305. 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 D 5664. The test data developed by ASTM D 5664 shall be used to develop modification factors for use at or near room temperature and at elevated temperatures and humidity in accordance with ASTM D 6841. 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 R802.1.3 when subjected to ASTM D 2898.
Interior fire-retardant-treated wood shall have a moisture content of not over 28 percent when tested in accordance with ASTM D 3201 procedures at 92 percent relative humidity. Interior fire-retardant-treated wood shall be tested in accordance with Section R802.1.3.5.1 or R802.1.3.5.2. 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 R802.1.3.5.1 for plywood and R802.1.3.5.2 for lumber.
Glued laminated timbers shall be manufactured and identified as required in ANSI/AITC A190.1 and ASTM D 3737.
Stress grading of structural log members of nonrectangular shape, as typically used in log buildings, shall be in accordance with ASTM D 3957. 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 to be accepted.
Structural capacities for structural composite lumber shall be established and monitored in accordance with ASTM D 5456.
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 AFPA/NDS. Components of roof-ceilings shall be fastened in accordance with Table R602.3(1).
Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. At all 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 when 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 a minimum of 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 a minimum of 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 a minimum of 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).

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 AF&PA Span Tables for Joists and Rafters.

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#310-1015-1020-124-6
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#211-317-823-0Note a
Douglas fir-larch#39-513-917-521-3
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#111-317-823-4Note 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#210-716-721-025-8
Douglas fir-larch#38-712-615-1019-5
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#29-1014-1018-922-11
Douglas fir-larch#37-811-214-217-4
Hem-firSS9-1015-620-5Note a
Hem-fir#19-815-219-723-11
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 = 0.0479kPa.

  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#29-1014-1018-922-11
Douglas fir-larch#37-811-214-217-4
Hem-firSS9-1015-620-5Note a
Hem-fir#19-815-219-723-11
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#28-912-1016-319-10
Douglas fir-larch#36-89-812-415-0
Hem-firSS8-1114-118-623-8
Hem-fir#18-913-516-1020-8
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-larchSS8-1114-018-523-4
Douglas fir-larch#18-712-615-1019-5
Douglas fir-larch#28-011-914-1018-2
Douglas fir-larch#36-18-1011-313-8
Hem-firSS8-513-317-522-3
Hem-fir#18-312-315-618-11
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-larchSS8-313-017-120-11
Douglas fir-larch#17-811-214-217-4
Douglas fir-larch#27-210-613-316-3
Douglas fir-larch#35-57-1110-012-3
Hem-firSS7-1012-316-220-6
Hem-fir#17-610-1113-1016-11
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 = 0.0479kPa.

  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 AF&PA; Span Tables for Joists and Rafters. 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 no 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 (0.785 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).

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

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 b11-618-023-5Note bNote b
Douglas fir-larch#111-117-422-5Note bNote b10-615-419-523-9Note b
Douglas fir-larch#210-1016-721-025-8Note b9-1014-418-222-325-9
Douglas fir-larch#38-712-615-1019-522-67-510-1013-916-919-6
Hem-firSS10-1017-022-5Note bNote b10-1017-022-5Note bNote b
Hem-fir#110 -716-821-10Note bNote b10-314-1118-1123-2Note 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 b10-516-020-324-9Note b
Douglas fir-larch#110-015-419-523-9Note b9-113-316-1020-723-10
Douglas fir-larch#29-1014-418-222-325-98-612-515-919-322-4
Douglas fir-larch#37-510-1013-916-919-66-59-511-1114-616-10
Hem-firSS9-1015-620-5Note bNote b9-1015-619-1124-4Note b
Hem-fir#19-814-1118-1123-2Note b8-1012-1116-520-023-3
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 b9-1014-718-622-7Note b
Douglas fir-larch#19-514-017-921-825-28-412-215-418-921-9
Douglas fir-larch#28-1113-116-720-323-67-911-414-417-720-4
Douglas fir-larch#36-99-1112-715-417-95-108-710-1013-315-5
Hem-firSS9-314-719-224-6Note b9-314-418-222-325-9
Hem-fir#19-113-817-421-124-68-111-1015-018-421-3
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-larchSS9-114-418-1023-4Note b8-1113-116-720-323-5
Douglas fir-larch#18-712-615-1019-522-67-510-1013-916-919-6
Douglas fir-larch#28-011-914-1018-221-06-1110-212-1015-818-3
Douglas fir-larch#36-18-1011-313-815-115-37-89-911-1013-9
Hem-firSS8-713-617-1022-9Note b8-712-1016-319-1023-0
Hem-fir#18-412-315-618-1121-117-310-713-516-419-0
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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#29-1015-620-525-8Note b9-1014-418-222-325-9
Douglas fir-larch#38-712-615-1019-522-67-510-1013-916-919-6
Hem-firSS9-1015-620-5Note bNote b9-1015-620-5Note bNote b
Hem-fir#19-815-219-1125-5Note b9-814-1118-1123-2Note 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 b9-614-1119-724-9Note b
Douglas fir-larch#19-114-418-1123-9Note b9-113-316-1020-723-10
Douglas fir-larch#28-1114-118-222-325-98-612-515-919-322-4
Douglas fir-larch#37-510-1013-916-919-66-59-511-1114-616-10
Hem-firSS8-1114-118-623-8Note b8-1114-118-623-8Note b
Hem-fir#18-913-918-123-1Note b8-912-1116-520-023-3
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 b8-1114-018-522-7Note b
Douglas fir-larch#18-713-617-921-825-28-412-215-418-921-9
Douglas fir-larch#28-513-116-720-323-67-911-414-417-720-4
Douglas fir-larch#36-99-1112-715-417-95-108-710-1013-315-5
Hem-firSS8-513-317-522-3Note b8-513-317-522-325-9
Hem-fir#18-312-1117-121-124-68-111-1015-018-421-3
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#28-112-315-716-621-97-110-813-616-018-10
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-larchSS8-313-017-22 1-10Note b8-313-016-720-323-5
Douglas fir-larch#18-012-615-1019-522-67-510-1013-916-919-6
Douglas fir-larch#27-1011-914-1018-221-06-1110-212-1015-818-3
Douglas fir-larch#36-18-1011-313-815-115-37-89-911-1013-9
Hem-firSS7-1012-316-220-825-17-1012-316-219-1023-0
Hem-fir#17-812-015-618-1121-117-310-713-516-419-0
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#17-1012-316-218-1122-67-611-114-016-519-6
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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 b10-015-920-124-6Note b
Douglas fir-larch#19-814-918-822-9Note b9-013-216-820-423-7
Douglas fir-larch#29-513-917-521-424-88-512-415-719-122-1
Douglas fir-larch#37-110-513-216-118-86-49-411-914-516-8
Hem-firSS9-614-1019-725-0Note b9-614-1019-724-1Note b
Hem-fir#19-314-418-222-225-98-912-1016-319-1023-0
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-larchSS9-114-418-1023-9Note b9-113-917-521-324-8
Douglas fir-larch#18-912-916-219-922-107-1011-514-517-820-5
Douglas fir-larch#28-211-1115-118-521-57-310-813-616-619-2
Douglas fir-larch#36-29-011-513-1116-25-68-110-312-614-6
Hem-firSS8-713-617-1022-9Note b8-713-617-120-1024-2
Hem-fir#18-512-515-919-322-37-711-114-117-219-11
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 b8-1114-118-521-1125-11
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-larchSS8-713-617-921-825-28-712-615-1019-522-6
Douglas fir-larch#17-1111-814-918-020-117-110-513-216-118-8
Douglas fir-larch#27-510-1113-916-1019-66-89-912-415-117-6
Douglas fir-larch#35-78-310-512-914-95-07-49-411-513-2
Hem-firSS8-112-916-921-424-88-112-415-719-122-1
Hem-fir#17-911-414-417-720-46-1110-212-1015-818-2
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-larchSS7-1112-615-1019-522-67-811-314-217-420-1
Douglas fir-larch#17-110-513-216-118-86-49-411-914-516-8
Douglas fir-larch#26-89-912-415-117-65-118-811-013-615-7
Douglas fir-larch#35-07-49-411-513-24-66-78-410-211-10
Hem-firSS7-611-1015-719-122-17-611-013-1117-019-9
Hem-fir#16-1110-212-1015-818-26-29-111-614-016-3
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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-larchSS8-513-317-622-426-08-513-317-020-924-0
Douglas fir-larch#18-212-015-318-721-77-711-214-117-320-0
Douglas fir-larch#27-811-314-317-520-27-110-513-216-118-8
Douglas fir-larch#35-108-610-913-215-35-57-1010-012-214-1
Hem-firSS8-012-616-621-125-68-012-616-620-423-7
Hem-fir#17-1011-914-1018-121-07-510-1013-916-919-5
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-larchSS7-812-115-1019-522-67-811-714-817-1120-10
Douglas fir-larch#17-110-513-216-118-86-79-812-214-1117-3
Douglas fir-larch#26-89-912-415-117-66-29-011-513-1116-2
Douglas fir-larch#35-07-49-411-513-24-86-108-810-612-3
Hem-firSS7-311-515-019-122-17-311-514-517-820-5
Hem-fir#16-1110-212-1015-818-26-59-511-1114-616-10
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-larchSS7-311-414-617-820-67-310-713-516-519-0
Douglas fir-larch#16-69-612-014-817-16-08-1011-213-715-9
Douglas fir-larch#26-18-1111-313-915-115-78-310-512-914-9
Douglas fir-larch#34-76-98-610-512-14-36-37-119-711-2
Hem-firSS6-1010-914-217-520-26-1010-513-216-118-8
Hem-fir#16-49-311-914-416-75-108-710-1013-315-5
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-larchSS6-810-13-015-1018-46-69-612-014-817-0
Douglas fir-larch#15-108-610-913-215-35-57-1010-012-214-1
Douglas fir-larch#25-57-1110-112-414-35-07-49-411-513-2
Douglas fir-larch#34-16-07-79-410-93-105-77-18-710-0
Hem-firSS6-49-1112-915-718-06-49-411-914-516-8
Hem-fir#15-88-310-612-1014-105-37-89-911-1013-9
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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#28-713-617-521-424-88-512-415-719-122-1
Douglas fir-larch#37-110-513-216-118-86-49-411-914-516-8
Hem-firSS8-713-617-1022-9Note b8-713-617-1022-9Note b
Hem-fir#18-513-317-522-225-98-512-1016-319-1023-0
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 b8-313-017-221-324-8
Douglas fir-larch#18-012-616-219-922-107-1011-514-517-820-5
Douglas fir-larch#27-1011-1115-118-521-57-310-813-616-619-2
Douglas fir-larch#36-29-011-513-1116-25-68-110-312-614-6
Hem-firSS7-1012-316-220-825-17-1012-316-220-824-2
Hem-fir#17-812-015-919-322-37-711-114-117-219-11
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-larchSS7-912-316-120-725-07-912-315-1019-522-6
Douglas fir-larch#17-611-814-918-020-117-110-513-216-118-8
Douglas fir-larch#27-410-1113-916-1019-66-89-912-415-117-6
Douglas fir-larch#35-78-310-512-914-95-07-49-411-513-2
Hem-firSS7-411-715-319-523-77-411-715-319-122-1
Hem-fir#17-211-414-417-720-46-1110-212-1015-818-2
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-larchSS7-311-415-019-122-67-311-314-217-420-1
Douglas fir-larch#17-010-513-216-118-86-49-411-914-516-8
Douglas fir-larch#26-89-912-415-117-65-118-811-013-615-7
Douglas fir-larch#35-07-49-411-513-24-66-78-410-211-10
Hem-firSS6-1010-914-218-021-116-1010-913-1117-019-9
Hem-fir#16-810-212-1015-818-26-29-111-614-016-3
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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-larchSS7-812-115-1120-324-87-812-115-1120-324-0
Douglas fir-larch#17-511-715-318-721-77-511-214-117-320-0
Douglas fir-larch#27-311-314-317-520-27-110-513-216-118-8
Douglas fir-larch#35-108-610-913-215-35-57-1010-012-214-1
Hem-firSS7-311-515-019-223-47-311-515-019-223-4
Hem-fir#17-111-214-818-121-07-110-1013-916-919-5
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 pineSS7-611-015-719-1124-37-611-1015-719-1124-3
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-larchSS7-011-014-518-522-57-011-014-517-1120-10
Douglas fir-larch#16-910-513-216-118-86-79-812-214-1117-3
Douglas fir-larch#26-79-912-415-117-66-29-011-513-1116-2
Douglas fir-larch#35-07-49-411-513-24-86-108-810-612-3
Hem-firSS6-710-413-817-521-26-710-413-817-520-5
Hem-fir#16-510-212-1015-818-26-59-511-1114-616-10
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-larchSS6-710-413-717-420-66-710-413-516-519-0
Douglas fir-larch#16-49-612-014-817-16-08-1011-213-715-9
Douglas fir-larch#26-18-1111-313-915-115-78-310-512-914-9
Douglas fir-larch#34-76-98-610-512-14-36-37-119-711-2
Hem-firSS6-29-912-1016-519-116-29-912-1016-118-8
Hem-fir#16-19-311-914-416-75-108-710-1013-315-5
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-larchSS6-19-712-715-1018-46-19-612-014-817-0
Douglas fir-larch#15-108-610-913-215-35-57-1010-012-214-1
Douglas fir-larch#25-57-1110-112-414-35-07-49-411-513-2
Douglas fir-larch#34-16-07-79-410-93-105-77-18-710-0
Hem-firSS5-99-111-1115-218-05-99-111-914-515-11
Hem-fir#15-88-310-612-1014-105-37-89-911-1013-9
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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-larchSS7-711-1015-819-522-67-711-1015-018-321-2
Douglas fir-larch#17-110-513-216-118-86-89-1012-515-217-7
Douglas fir-larch#26-89-912-415-117-66-39-211-814-216-6
Douglas fir-larch#35-07-49-411-513-24-96-118-910-912-5
Hem-firSS7-211-314-918-1022-17-211-314-818-020-10
Hem-fir#16-1110-212-1015-818-26-69-712-114-1017-2
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-larchSS6-1010-913-916-1019-66-1010-313-015-1018-4
Douglas fir-larch#16-29-011-513-1116-25-108-610-913-215-3
Douglas fir-larch#25-98-510-813-115-25-57-1110-112-414-3
Douglas fir-larch#34-46-48-19-1011-54-16-07-79-410-9
Hem-firSS6-610-213-516-619-26-610-112-915-718-0
Hem-fir#16-08-911-213-715-95-88-310-612-1014-10
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-larchSS6-59-1112-715-417-96-59-411-1014-516-9
Douglas fir-larch#15-78-310-512-914-95-47-99-1012-013-11
Douglas fir-larch#25-37-89-911-1113-105-07-39-211-313-0
Douglas fir-larch#34-05-107-49-010-53-95-66-118-69-10
Hem-firSS6-19-712-415-117-46-19-211-814-215-5
Hem-fir#15-68-010-212-514-55-27-79-711-813-7
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-larchSS6-08-1011-313-915-115-98-410-712-1115-0
Douglas fir-larch#15-07-49-411-513-24-96-118-910-912-5
Douglas fir-larch#24-86-118-910-812-44-56-68-310-011-8
Douglas fir-larch#33-75-26-78-19-43-44-116-37-78-10
Hem-firSS5-88-811-013-613-115-78-310-512-412-4
Hem-fir#14-117-29-111-112-104-76-98-710-612-2
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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-larchSS6-1010-914-318-222-16-1010-914-318-221-2
Douglas fir-larch#16-710-513-216-118-86-79-1012-515-217-7
Douglas fir-larch#26-69-912-415-117-66-39-211-814-216-6
Douglas fir-larch#35-07-49-411-513-24-96-118-910-912-5
Hem-firSS6-610-213-517-220-106-610-213-517-220-10
Hem-fir#16-410-012-1015-818-26-49-712-114-1017-2
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-larchSS6-39-1012-1116-619-66-39-1012-1115-1018-4
Douglas fir-larch#16-09-011-513-1116-25-108-610-913-215-3
Douglas fir-larch#25-98-510-813-115-25-57-1110-112-414-3
Douglas fir-larch#34-46-48-19-1011-54-16-07-79-410-9
Hem-firSS5-119-312-215-718-115-119-312-215-718-0
Hem-fir#15-98-911-213-715-95-88-310-612-1014-10
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-larchSS5-109-312-215-417-95-109-311-1014-516-9
Douglas fir-larch#15-78-310-512-914-95-47-99-1012-013-11
Douglas fir-larch#25-37-89-911-1113-105-07-39-211-313-0
Douglas fir-larch#34-05-107-49-010-53-95-66-118-69-10
Hem-firSS5-68-811-614-817-45-68-811-614-215-5
Hem-fir#15-58-010-212-514-55-27-79-711-813-7
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-larchSS5-58-711-313-915-115-58-410-712-1115-0
Douglas fir-larch#15-07-49-411-513-24-96-118-910-912-5
Douglas fir-larch#24-86-118-910-812-44-56-68-310-011-8
Douglas fir-larch#33-75-26-78-19-43-44-116-37-78-10
Hem-firSS5-28-110-813-613-115-28-110-512-412-4
Hem-fir#14-117-29-111-112-104-76-98-710-612-2
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. When ceiling joists or rafter ties are located higher in the attic space, the rafter spans shall be multiplied by the factors given below:

    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
SLOPE
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
24346