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// CODE SNIPPET

R802.4.1 Rafter Size

2020 Residential Code of New York State > 8 Roof-Ceiling Construction > R802 Wood Roof Framing > R802.4 Rafters > R802.4.1 Rafter Size
JUMP TO FULL CODE CHAPTER

Rafters shall be sized based on the rafter spans in Tables R802.4.1(1) through R802.4.1(8). Rafter spans shall be measured along the horizontal projection of the rafter. For other grades and species and for other loading conditions, refer to the AWC STJR.

TABLE R802.4.1(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 R802.4.1(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 R802.4.1(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 R802.4.1(4)

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 R802.4.1(5)

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 R802.4.1(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 R802.4.1(7)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground snow load = 70 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-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 R802.4.1(8)

RAFTER SPANS FOR COMMON LUMBER SPECIES (Ground snow load = 70 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-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.

Related Code Sections


R802.4.1 Roof-Ceiling Construction, Rafter Size
Rafters shall be sized based on the rafter spans in Tables R802.4.1(1) through R802.4.1(8). Rafter spans shall be measured along the horizontal ...
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Roof rafter size and thickness shall be determined in accordance with the limits set forth in Table R804.3.2.1(1) based on the horizontal projection ...
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Roof rafter size and thickness shall be determined in accordance with the limits set forth in Table R804.3.2.1(1) based on the horizontal projection ...
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R804.3.2.2 Roof-Ceiling Construction, Roof Rafter Support Brace
Where used to reduce roof rafter spans in determining roof rafter sizes, a roof rafter support brace shall meet all of the following conditions ...
2020 Residential Code of New York State > 8 Roof-Ceiling Construction > R804 Cold-Formed Steel Roof Framing > R804.3 Roof Construction > R804.3.2 Roof Rafters > R804.3.2.2 Roof Rafter Support Brace
R804.3.2 Roof-Ceiling Construction, Roof Rafters
Roof rafter size and thickness shall be determined in accordance with the limits set forth in Table R804.3.2.1(1) based ...
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