Header and floor girder spans (2021 IRC)
A two-ply 2×10 header in an exterior bearing wall supporting roof and ceiling spans up to 6’10” at 30 psf ground snow and a 24-foot building width, and requires 2 jack studs at each end, per 2021 IRC Table R602.7(1).
Both tables are here in full: 2021 IRC Table R602.7(1) for exterior bearing walls, and 2021 IRC Table R602.7(2) — the interior floor girder table — for the built-up girders and headers in an interior bearing wall, read by how many floors they carry rather than by ground snow load.
How to read these tables
The size column pairs a ply count with a lumber size. “2-2×10” means two 2×10s fastened together; a 3-2×12 is three 2×12s fastened together. On this page the same rows are printed as “2 × 2×10”.
NJ is the number of jack studs required at each end of the header, and it is printed next to each span here as “(2 jacks)”. The tables also assume the top of the header is laterally braced — both are facts of the table, stated in its footnotes.
Building width is measured perpendicular to the ridge. Where the ground snow load is less than 30 psf and the roof live load is 20 psf or less, the table’s own instruction is to use the 30 psf ground snow columns.
Point loads, cantilevers beyond the table footnotes, unusual snow loads, or anything else outside the table's stated conditions — that's an engineer's question.
Exterior bearing walls
2021 IRC Table R602.7(1), one table per supporting condition. Columns are ground snow load in psf by building width in feet; each cell is the allowable span with the jack studs required at each end.
Supporting roof and ceiling
| Header | 30 psf ground snow | 50 psf ground snow | 70 psf ground snow | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | |
| 1 × 2×6 | 4’0” (1 jack) | 3’1” (2 jacks) | 2’7” (2 jacks) | 3’5” (1 jack) | 2’8” (2 jacks) | 2’3” (2 jacks) | 3’0” (2 jacks) | 2’4” (2 jacks) | 2’0” (2 jacks) |
| 1 × 2×8 | 5’1” (2 jacks) | 3’11” (2 jacks) | 3’3” (2 jacks) | 4’4” (2 jacks) | 3’4” (2 jacks) | 2’10” (2 jacks) | 3’10” (2 jacks) | 3’0” (2 jacks) | 2’6” (3 jacks) |
| 1 × 2×10 | 6’0” (2 jacks) | 4’8” (2 jacks) | 3’11” (2 jacks) | 5’2” (2 jacks) | 4’0” (2 jacks) | 3’4” (3 jacks) | 4’7” (2 jacks) | 3’6” (3 jacks) | 3’0” (3 jacks) |
| 1 × 2×12 | 7’1” (2 jacks) | 5’5” (2 jacks) | 4’7” (3 jacks) | 6’1” (2 jacks) | 4’8” (3 jacks) | 3’11” (3 jacks) | 5’5” (2 jacks) | 4’2” (3 jacks) | 3’6” (3 jacks) |
| 2 × 2×4 | 4’0” (1 jack) | 3’1” (1 jack) | 2’7” (1 jack) | 3’5” (1 jack) | 2’7” (1 jack) | 2’2” (1 jack) | 3’0” (1 jack) | 2’4” (1 jack) | 2’0” (1 jack) |
| 2 × 2×6 | 6’0” (1 jack) | 4’7” (1 jack) | 3’10” (1 jack) | 5’1” (1 jack) | 3’11” (1 jack) | 3’3” (2 jacks) | 4’6” (1 jack) | 3’6” (2 jacks) | 2’11” (2 jacks) |
| 2 × 2×8 | 7’7” (1 jack) | 5’9” (1 jack) | 4’10” (2 jacks) | 6’5” (1 jack) | 5’0” (2 jacks) | 4’2” (2 jacks) | 5’9” (1 jack) | 4’5” (2 jacks) | 3’9” (2 jacks) |
| 2 × 2×10 | 9’0” (1 jack) | 6’10” (2 jacks) | 5’9” (2 jacks) | 7’8” (2 jacks) | 5’11” (2 jacks) | 4’11” (2 jacks) | 6’9” (2 jacks) | 5’3” (2 jacks) | 4’5” (2 jacks) |
| 2 × 2×12 | 10’7” (2 jacks) | 8’1” (2 jacks) | 6’10” (2 jacks) | 9’0” (2 jacks) | 6’11” (2 jacks) | 5’10” (2 jacks) | 8’0” (2 jacks) | 6’2” (2 jacks) | 5’2” (3 jacks) |
| 3 × 2×8 | 9’5” (1 jack) | 7’3” (1 jack) | 6’1” (1 jack) | 8’1” (1 jack) | 6’3” (1 jack) | 5’3” (2 jacks) | 7’2” (1 jack) | 5’6” (2 jacks) | 4’8” (2 jacks) |
| 3 × 2×10 | 11’3” (1 jack) | 8’7” (1 jack) | 7’3” (2 jacks) | 9’7” (1 jack) | 7’4” (2 jacks) | 6’2” (2 jacks) | 8’6” (1 jack) | 6’7” (2 jacks) | 5’6” (2 jacks) |
| 3 × 2×12 | 13’2” (1 jack) | 10’1” (2 jacks) | 8’6” (2 jacks) | 11’3” (2 jacks) | 8’8” (2 jacks) | 7’4” (2 jacks) | 10’0” (2 jacks) | 7’9” (2 jacks) | 6’6” (2 jacks) |
| 4 × 2×8 | 10’11” (1 jack) | 8’4” (1 jack) | 7’0” (1 jack) | 9’4” (1 jack) | 7’2” (1 jack) | 6’0” (1 jack) | 8’3” (1 jack) | 6’4” (1 jack) | 5’4” (2 jacks) |
| 4 × 2×10 | 12’11” (1 jack) | 9’11” (1 jack) | 8’4” (1 jack) | 11’1” (1 jack) | 8’6” (1 jack) | 7’2” (2 jacks) | 9’10” (1 jack) | 7’7” (2 jacks) | 6’4” (2 jacks) |
| 4 × 2×12 | 15’3” (1 jack) | 11’8” (1 jack) | 9’10” (2 jacks) | 13’0” (1 jack) | 10’0” (2 jacks) | 8’5” (2 jacks) | 11’7” (1 jack) | 8’11” (2 jacks) | 7’6” (2 jacks) |
2021 IRC Table R602.7(1) — exterior bearing wall header supporting roof and ceiling, No. 2 grade Douglas fir-larch, hem-fir, southern pine or spruce-pine-fir, ground snow load in psf by building width in feet. table source
Supporting roof, ceiling and one center-bearing floor
| Header | 30 psf ground snow | 50 psf ground snow | 70 psf ground snow | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | |
| 1 × 2×6 | 3’3” (1 jack) | 2’7” (2 jacks) | 2’2” (2 jacks) | 3’0” (2 jacks) | 2’4” (2 jacks) | 2’0” (2 jacks) | 2’9” (2 jacks) | 2’2” (2 jacks) | 1’10” (2 jacks) |
| 1 × 2×8 | 4’1” (2 jacks) | 3’3” (2 jacks) | 2’9” (2 jacks) | 3’9” (2 jacks) | 3’0” (2 jacks) | 2’6” (3 jacks) | 3’6” (2 jacks) | 2’9” (2 jacks) | 2’4” (3 jacks) |
| 1 × 2×10 | 4’11” (2 jacks) | 3’10” (2 jacks) | 3’3” (3 jacks) | 4’6” (2 jacks) | 3’6” (3 jacks) | 3’0” (3 jacks) | 4’1” (2 jacks) | 3’3” (3 jacks) | 2’9” (3 jacks) |
| 1 × 2×12 | 5’9” (2 jacks) | 4’6” (3 jacks) | 3’10” (3 jacks) | 5’3” (2 jacks) | 4’2” (3 jacks) | 3’6” (3 jacks) | 4’10” (3 jacks) | 3’10” (3 jacks) | 3’3” (4 jacks) |
| 2 × 2×4 | 3’3” (1 jack) | 2’6” (1 jack) | 2’2” (1 jack) | 3’0” (1 jack) | 2’4” (1 jack) | 2’0” (1 jack) | 2’8” (1 jack) | 2’2” (1 jack) | 1’10” (1 jack) |
| 2 × 2×6 | 4’10” (1 jack) | 3’9” (1 jack) | 3’3” (2 jacks) | 4’5” (1 jack) | 3’6” (2 jacks) | 3’0” (2 jacks) | 4’1” (1 jack) | 3’3” (2 jacks) | 2’9” (2 jacks) |
| 2 × 2×8 | 6’1” (1 jack) | 4’10” (2 jacks) | 4’1” (2 jacks) | 5’7” (2 jacks) | 4’5” (2 jacks) | 3’9” (2 jacks) | 5’2” (2 jacks) | 4’1” (2 jacks) | 3’6” (2 jacks) |
| 2 × 2×10 | 7’3” (2 jacks) | 5’8” (2 jacks) | 4’10” (2 jacks) | 6’8” (2 jacks) | 5’3” (2 jacks) | 4’5” (2 jacks) | 6’1” (2 jacks) | 4’10” (2 jacks) | 4’1” (2 jacks) |
| 2 × 2×12 | 8’6” (2 jacks) | 6’8” (2 jacks) | 5’8” (2 jacks) | 7’10” (2 jacks) | 6’2” (2 jacks) | 5’3” (3 jacks) | 7’2” (2 jacks) | 5’8” (2 jacks) | 4’10” (3 jacks) |
| 3 × 2×8 | 7’8” (1 jack) | 6’0” (1 jack) | 5’1” (2 jacks) | 7’0” (1 jack) | 5’6” (2 jacks) | 4’8” (2 jacks) | 6’5” (1 jack) | 5’1” (2 jacks) | 4’4” (2 jacks) |
| 3 × 2×10 | 9’1” (1 jack) | 7’2” (2 jacks) | 6’1” (2 jacks) | 8’4” (1 jack) | 6’7” (2 jacks) | 5’7” (2 jacks) | 7’8” (2 jacks) | 6’1” (2 jacks) | 5’2” (2 jacks) |
| 3 × 2×12 | 10’8” (2 jacks) | 8’5” (2 jacks) | 7’2” (2 jacks) | 9’10” (2 jacks) | 7’8” (2 jacks) | 6’7” (2 jacks) | 9’0” (2 jacks) | 7’1” (2 jacks) | 6’1” (2 jacks) |
| 4 × 2×8 | 8’10” (1 jack) | 6’11” (1 jack) | 5’11” (1 jack) | 8’1” (1 jack) | 6’4” (1 jack) | 5’5” (2 jacks) | 7’5” (1 jack) | 5’11” (1 jack) | 5’0” (2 jacks) |
| 4 × 2×10 | 10’6” (1 jack) | 8’3” (2 jacks) | 7’0” (2 jacks) | 9’8” (1 jack) | 7’7” (2 jacks) | 6’5” (2 jacks) | 8’10” (1 jack) | 7’0” (2 jacks) | 6’0” (2 jacks) |
| 4 × 2×12 | 12’4” (1 jack) | 9’8” (2 jacks) | 8’3” (2 jacks) | 11’4” (2 jacks) | 8’11” (2 jacks) | 7’7” (2 jacks) | 10’4” (2 jacks) | 8’3” (2 jacks) | 7’0” (2 jacks) |
2021 IRC Table R602.7(1) — exterior bearing wall header supporting roof, ceiling and one center-bearing floor, No. 2 grade Douglas fir-larch, hem-fir, southern pine or spruce-pine-fir, ground snow load in psf by building width in feet. table source
Supporting roof, ceiling and one clear-span floor
| Header | 30 psf ground snow | 50 psf ground snow | 70 psf ground snow | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | |
| 1 × 2×6 | 2’11” (2 jacks) | 2’3” (2 jacks) | 1’11” (2 jacks) | 2’9” (2 jacks) | 2’1” (2 jacks) | 1’9” (2 jacks) | 2’7” (2 jacks) | 2’0” (2 jacks) | 1’8” (2 jacks) |
| 1 × 2×8 | 3’9” (2 jacks) | 2’10” (2 jacks) | 2’5” (3 jacks) | 3’6” (2 jacks) | 2’8” (2 jacks) | 2’3” (3 jacks) | 3’3” (2 jacks) | 2’6” (3 jacks) | 2’2” (3 jacks) |
| 1 × 2×10 | 4’5” (2 jacks) | 3’5” (3 jacks) | 2’10” (3 jacks) | 4’2” (2 jacks) | 3’2” (3 jacks) | 2’8” (3 jacks) | 3’11” (2 jacks) | 3’0” (3 jacks) | 2’6” (3 jacks) |
| 1 × 2×12 | 5’2” (2 jacks) | 4’0” (3 jacks) | 3’4” (3 jacks) | 4’10” (3 jacks) | 3’9” (3 jacks) | 3’2” (4 jacks) | 4’7” (3 jacks) | 3’6” (3 jacks) | 3’0” (4 jacks) |
| 2 × 2×4 | 2’11” (1 jack) | 2’3” (1 jack) | 1’10” (1 jack) | 2’9” (1 jack) | 2’1” (1 jack) | 1’9” (1 jack) | 2’7” (1 jack) | 2’0” (1 jack) | 1’8” (1 jack) |
| 2 × 2×6 | 4’4” (1 jack) | 3’4” (2 jacks) | 2’10” (2 jacks) | 4’1” (1 jack) | 3’2” (2 jacks) | 2’8” (2 jacks) | 3’10” (1 jack) | 3’0” (2 jacks) | 2’6” (2 jacks) |
| 2 × 2×8 | 5’6” (2 jacks) | 4’3” (2 jacks) | 3’7” (2 jacks) | 5’2” (2 jacks) | 4’0” (2 jacks) | 3’4” (2 jacks) | 4’10” (2 jacks) | 3’9” (2 jacks) | 3’2” (2 jacks) |
| 2 × 2×10 | 6’7” (2 jacks) | 5’0” (2 jacks) | 4’2” (2 jacks) | 6’1” (2 jacks) | 4’9” (2 jacks) | 4’0” (2 jacks) | 5’9” (2 jacks) | 4’5” (2 jacks) | 3’9” (3 jacks) |
| 2 × 2×12 | 7’9” (2 jacks) | 5’11” (2 jacks) | 4’11” (3 jacks) | 7’2” (2 jacks) | 5’7” (2 jacks) | 4’8” (3 jacks) | 6’9” (2 jacks) | 5’3” (3 jacks) | 4’5” (3 jacks) |
| 3 × 2×8 | 6’11” (1 jack) | 5’3” (2 jacks) | 4’5” (2 jacks) | 6’5” (1 jack) | 5’0” (2 jacks) | 4’2” (2 jacks) | 6’1” (1 jack) | 4’8” (2 jacks) | 4’0” (2 jacks) |
| 3 × 2×10 | 8’3” (2 jacks) | 6’3” (2 jacks) | 5’3” (2 jacks) | 7’8” (2 jacks) | 5’11” (2 jacks) | 5’0” (2 jacks) | 7’3” (2 jacks) | 5’7” (2 jacks) | 4’8” (2 jacks) |
| 3 × 2×12 | 9’8” (2 jacks) | 7’5” (2 jacks) | 6’2” (2 jacks) | 9’0” (2 jacks) | 7’0” (2 jacks) | 5’10” (2 jacks) | 8’6” (2 jacks) | 6’7” (2 jacks) | 5’6” (3 jacks) |
| 4 × 2×8 | 8’0” (1 jack) | 6’1” (1 jack) | 5’1” (2 jacks) | 7’5” (1 jack) | 5’9” (2 jacks) | 4’10” (2 jacks) | 7’0” (1 jack) | 5’5” (2 jacks) | 4’7” (2 jacks) |
| 4 × 2×10 | 9’6” (1 jack) | 7’3” (2 jacks) | 6’1” (2 jacks) | 8’10” (1 jack) | 6’10” (2 jacks) | 5’9” (2 jacks) | 8’4” (1 jack) | 6’5” (2 jacks) | 5’5” (2 jacks) |
| 4 × 2×12 | 11’2” (2 jacks) | 8’6” (2 jacks) | 7’2” (2 jacks) | 10’5” (2 jacks) | 8’0” (2 jacks) | 6’9” (2 jacks) | 9’10” (2 jacks) | 7’7” (2 jacks) | 6’5” (2 jacks) |
2021 IRC Table R602.7(1) — exterior bearing wall header supporting roof, ceiling and one clear-span floor, No. 2 grade Douglas fir-larch, hem-fir, southern pine or spruce-pine-fir, ground snow load in psf by building width in feet. table source
Supporting roof, ceiling and two center-bearing floors
| Header | 30 psf ground snow | 50 psf ground snow | 70 psf ground snow | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | |
| 1 × 2×6 | 2’8” (2 jacks) | 2’1” (2 jacks) | 1’10” (2 jacks) | 2’7” (2 jacks) | 2’0” (2 jacks) | 1’9” (2 jacks) | 2’5” (2 jacks) | 1’11” (2 jacks) | 1’8” (2 jacks) |
| 1 × 2×8 | 3’5” (2 jacks) | 2’8” (2 jacks) | 2’4” (3 jacks) | 3’3” (2 jacks) | 2’7” (2 jacks) | 2’2” (3 jacks) | 3’1” (2 jacks) | 2’5” (3 jacks) | 2’1” (3 jacks) |
| 1 × 2×10 | 4’0” (2 jacks) | 3’2” (3 jacks) | 2’9” (3 jacks) | 3’10” (2 jacks) | 3’1” (3 jacks) | 2’7” (3 jacks) | 3’8” (2 jacks) | 2’11” (3 jacks) | 2’5” (3 jacks) |
| 1 × 2×12 | 4’9” (3 jacks) | 3’9” (3 jacks) | 3’2” (4 jacks) | 4’6” (3 jacks) | 3’7” (3 jacks) | 3’1” (4 jacks) | 4’3” (3 jacks) | 3’5” (3 jacks) | 2’11” (4 jacks) |
| 2 × 2×4 | 2’8” (1 jack) | 2’1” (1 jack) | 1’9” (1 jack) | 2’6” (1 jack) | 2’0” (1 jack) | 1’8” (1 jack) | 2’5” (1 jack) | 1’11” (1 jack) | 1’7” (1 jack) |
| 2 × 2×6 | 4’0” (1 jack) | 3’2” (2 jacks) | 2’8” (2 jacks) | 3’9” (1 jack) | 3’0” (2 jacks) | 2’7” (2 jacks) | 3’7” (1 jack) | 2’10” (2 jacks) | 2’5” (2 jacks) |
| 2 × 2×8 | 5’0” (2 jacks) | 4’0” (2 jacks) | 3’5” (2 jacks) | 4’10” (2 jacks) | 3’10” (2 jacks) | 3’3” (2 jacks) | 4’7” (2 jacks) | 3’7” (2 jacks) | 3’1” (2 jacks) |
| 2 × 2×10 | 6’0” (2 jacks) | 4’9” (2 jacks) | 4’0” (2 jacks) | 5’8” (2 jacks) | 4’6” (2 jacks) | 3’10” (3 jacks) | 5’5” (2 jacks) | 4’3” (2 jacks) | 3’8” (3 jacks) |
| 2 × 2×12 | 7’0” (2 jacks) | 5’7” (2 jacks) | 4’9” (3 jacks) | 6’8” (2 jacks) | 5’4” (3 jacks) | 4’6” (3 jacks) | 6’4” (2 jacks) | 5’0” (3 jacks) | 4’3” (3 jacks) |
| 3 × 2×8 | 6’4” (1 jack) | 5’0” (2 jacks) | 4’3” (2 jacks) | 6’0” (1 jack) | 4’9” (2 jacks) | 4’1” (2 jacks) | 5’8” (2 jacks) | 4’6” (2 jacks) | 3’10” (2 jacks) |
| 3 × 2×10 | 7’6” (2 jacks) | 5’11” (2 jacks) | 5’1” (2 jacks) | 7’1” (2 jacks) | 5’8” (2 jacks) | 4’10” (2 jacks) | 6’9” (2 jacks) | 5’4” (2 jacks) | 4’7” (2 jacks) |
| 3 × 2×12 | 8’10” (2 jacks) | 7’0” (2 jacks) | 5’11” (2 jacks) | 8’5” (2 jacks) | 6’8” (2 jacks) | 5’8” (3 jacks) | 8’0” (2 jacks) | 6’4” (2 jacks) | 5’4” (3 jacks) |
| 4 × 2×8 | 7’3” (1 jack) | 5’9” (1 jack) | 4’11” (2 jacks) | 6’11” (1 jack) | 5’6” (2 jacks) | 4’8” (2 jacks) | 6’7” (1 jack) | 5’2” (2 jacks) | 4’5” (2 jacks) |
| 4 × 2×10 | 8’8” (1 jack) | 6’10” (2 jacks) | 5’10” (2 jacks) | 8’3” (2 jacks) | 6’6” (2 jacks) | 5’7” (2 jacks) | 7’10” (2 jacks) | 6’2” (2 jacks) | 5’3” (2 jacks) |
| 4 × 2×12 | 10’2” (2 jacks) | 8’1” (2 jacks) | 6’10” (2 jacks) | 9’8” (2 jacks) | 7’8” (2 jacks) | 6’7” (2 jacks) | 9’2” (2 jacks) | 7’3” (2 jacks) | 6’2” (2 jacks) |
2021 IRC Table R602.7(1) — exterior bearing wall header supporting roof, ceiling and two center-bearing floors, No. 2 grade Douglas fir-larch, hem-fir, southern pine or spruce-pine-fir, ground snow load in psf by building width in feet. table source
Supporting roof, ceiling and two clear-span floors
| Header | 30 psf ground snow | 50 psf ground snow | 70 psf ground snow | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | 12 ft wide | 24 ft wide | 36 ft wide | |
| 1 × 2×6 | 2’3” (2 jacks) | 1’9” (2 jacks) | 1’5” (2 jacks) | 2’3” (2 jacks) | 1’9” (2 jacks) | 1’5” (3 jacks) | 2’2” (2 jacks) | 1’8” (2 jacks) | 1’5” (3 jacks) |
| 1 × 2×8 | 2’10” (2 jacks) | 2’2” (3 jacks) | 1’10” (3 jacks) | 2’10” (2 jacks) | 2’2” (3 jacks) | 1’10” (3 jacks) | 2’9” (2 jacks) | 2’1” (3 jacks) | 1’10” (3 jacks) |
| 1 × 2×10 | 3’4” (2 jacks) | 2’7” (3 jacks) | 2’2” (3 jacks) | 3’4” (3 jacks) | 2’7” (3 jacks) | 2’2” (4 jacks) | 3’3” (3 jacks) | 2’6” (3 jacks) | 2’2” (4 jacks) |
| 1 × 2×12 | 4’0” (3 jacks) | 3’0” (3 jacks) | 2’7” (4 jacks) | 4’0” (3 jacks) | 3’0” (4 jacks) | 2’7” (4 jacks) | 3’10” (3 jacks) | 3’0” (4 jacks) | 2’6” (4 jacks) |
| 2 × 2×4 | 2’3” (1 jack) | 1’8” (1 jack) | 1’4” (1 jack) | 2’3” (1 jack) | 1’8” (1 jack) | 1’4” (1 jack) | 2’2” (1 jack) | 1’8” (1 jack) | 1’4” (2 jacks) |
| 2 × 2×6 | 3’4” (1 jack) | 2’6” (2 jacks) | 2’2” (2 jacks) | 3’4” (2 jacks) | 2’6” (2 jacks) | 2’2” (2 jacks) | 3’3” (2 jacks) | 2’6” (2 jacks) | 2’1” (2 jacks) |
| 2 × 2×8 | 4’3” (2 jacks) | 3’3” (2 jacks) | 2’8” (2 jacks) | 4’3” (2 jacks) | 3’3” (2 jacks) | 2’8” (2 jacks) | 4’1” (2 jacks) | 3’2” (2 jacks) | 2’8” (3 jacks) |
| 2 × 2×10 | 5’0” (2 jacks) | 3’10” (2 jacks) | 3’2” (3 jacks) | 5’0” (2 jacks) | 3’10” (2 jacks) | 3’2” (3 jacks) | 4’10” (2 jacks) | 3’9” (3 jacks) | 3’2” (3 jacks) |
| 2 × 2×12 | 5’11” (2 jacks) | 4’6” (3 jacks) | 3’9” (3 jacks) | 5’11” (2 jacks) | 4’6” (3 jacks) | 3’9” (3 jacks) | 5’8” (2 jacks) | 4’5” (3 jacks) | 3’9” (3 jacks) |
| 3 × 2×8 | 5’3” (1 jack) | 4’0” (2 jacks) | 3’5” (2 jacks) | 5’3” (2 jacks) | 4’0” (2 jacks) | 3’5” (2 jacks) | 5’1” (2 jacks) | 3’11” (2 jacks) | 3’4” (2 jacks) |
| 3 × 2×10 | 6’3” (2 jacks) | 4’9” (2 jacks) | 4’0” (2 jacks) | 6’3” (2 jacks) | 4’9” (2 jacks) | 4’0” (2 jacks) | 6’1” (2 jacks) | 4’8” (2 jacks) | 4’0” (3 jacks) |
| 3 × 2×12 | 7’5” (2 jacks) | 5’8” (2 jacks) | 4’9” (3 jacks) | 7’5” (2 jacks) | 5’8” (2 jacks) | 4’9” (3 jacks) | 7’2” (2 jacks) | 5’6” (3 jacks) | 4’8” (3 jacks) |
| 4 × 2×8 | 6’1” (1 jack) | 4’8” (2 jacks) | 3’11” (2 jacks) | 6’1” (1 jack) | 4’8” (2 jacks) | 3’11” (2 jacks) | 5’11” (1 jack) | 4’7” (2 jacks) | 3’10” (2 jacks) |
| 4 × 2×10 | 7’3” (2 jacks) | 5’6” (2 jacks) | 4’8” (2 jacks) | 7’3” (2 jacks) | 5’6” (2 jacks) | 4’8” (2 jacks) | 7’0” (2 jacks) | 5’5” (2 jacks) | 4’7” (2 jacks) |
| 4 × 2×12 | 8’6” (2 jacks) | 6’6” (2 jacks) | 5’6” (2 jacks) | 8’6” (2 jacks) | 6’6” (2 jacks) | 5’6” (2 jacks) | 8’3” (2 jacks) | 6’4” (2 jacks) | 5’4” (3 jacks) |
2021 IRC Table R602.7(1) — exterior bearing wall header supporting roof, ceiling and two clear-span floors, No. 2 grade Douglas fir-larch, hem-fir, southern pine or spruce-pine-fir, ground snow load in psf by building width in feet. table source
Interior floor girder spans — 2021 IRC Table R602.7(2)
This is the floor girder table. The beam running down the middle of a basement or crawlspace that the floor joists land on, the built-up girder in an interior bearing wall, the header across an opening in one — the code lists them all in 2021 IRC Table R602.7(2), under interior bearing walls, and this is that table in full.
It is read by how many floors the girder carries. The row groups below are the supporting conditions 2021 IRC Table R602.7(2) publishes — one floor only and two floors — with the built-up size under each, the building width in feet across the top, and the jack studs each end requires printed next to every span. Ground snow load does not appear on this table: that is an exterior-wall column, because an interior girder is not carrying the roof.
| Header | Building width (feet) | ||
|---|---|---|---|
| 12 ft | 24 ft | 36 ft | |
| Supporting one floor only | |||
| 2 × 2×4 | 4’1” (1 jack) | 2’10” (1 jack) | 2’4” (1 jack) |
| 2 × 2×6 | 6’1” (1 jack) | 4’4” (1 jack) | 3’6” (1 jack) |
| 2 × 2×8 | 7’9” (1 jack) | 5’5” (1 jack) | 4’5” (2 jacks) |
| 2 × 2×10 | 9’2” (1 jack) | 6’6” (2 jacks) | 5’3” (2 jacks) |
| 2 × 2×12 | 10’9” (1 jack) | 7’7” (2 jacks) | 6’3” (2 jacks) |
| 3 × 2×8 | 9’8” (1 jack) | 6’10” (1 jack) | 5’7” (1 jack) |
| 3 × 2×10 | 11’5” (1 jack) | 8’1” (1 jack) | 6’7” (2 jacks) |
| 3 × 2×12 | 13’6” (1 jack) | 9’6” (2 jacks) | 7’9” (2 jacks) |
| 4 × 2×8 | 11’2” (1 jack) | 7’11” (1 jack) | 6’5” (1 jack) |
| 4 × 2×10 | 13’3” (1 jack) | 9’4” (1 jack) | 7’8” (1 jack) |
| 4 × 2×12 | 15’7” (1 jack) | 11’0” (1 jack) | 9’0” (2 jacks) |
| Supporting two floors | |||
| 2 × 2×4 | 2’7” (1 jack) | 1’11” (1 jack) | 1’7” (1 jack) |
| 2 × 2×6 | 3’11” (1 jack) | 2’11” (2 jacks) | 2’5” (2 jacks) |
| 2 × 2×8 | 5’0” (1 jack) | 3’8” (2 jacks) | 3’1” (2 jacks) |
| 2 × 2×10 | 5’11” (2 jacks) | 4’4” (2 jacks) | 3’7” (2 jacks) |
| 2 × 2×12 | 6’11” (2 jacks) | 5’2” (2 jacks) | 4’3” (3 jacks) |
| 3 × 2×8 | 6’3” (1 jack) | 4’7” (2 jacks) | 3’10” (2 jacks) |
| 3 × 2×10 | 7’5” (1 jack) | 5’6” (2 jacks) | 4’6” (2 jacks) |
| 3 × 2×12 | 8’8” (2 jacks) | 6’5” (2 jacks) | 5’4” (2 jacks) |
| 4 × 2×8 | 7’2” (1 jack) | 5’4” (1 jack) | 4’5” (2 jacks) |
| 4 × 2×10 | 8’6” (1 jack) | 6’4” (2 jacks) | 5’3” (2 jacks) |
| 4 × 2×12 | 10’1” (1 jack) | 7’5” (2 jacks) | 6’2” (2 jacks) |
2021 IRC Table R602.7(2) — interior bearing wall header, No. 2 grade Douglas fir-larch, hem-fir, southern pine or spruce-pine-fir, by building width in feet. table source
The jack studs, and the stud table they come from
A header is a beam inside a stud wall, and the jack studs counted at each end of every span above are studs like any other in that wall. How big those studs must be and how far apart they may stand is 2021 IRC Table R602.3(5), which has its own page: wall stud spacing, with the full table, its footnotes and the R602.3.1 exceptions.
Common questions
Where is the floor girder span table in the 2021 IRC?
Interior floor girders are 2021 IRC Table R602.7(2) — the interior bearing wall table, and it is on this page in full. It is read by how many floors the girder carries (one floor only or two floors), the built-up size, and the building width in feet; each cell gives the allowable span and the jack studs required at each end. The girder over an exterior opening is a different table, R602.7(1) above it, because that one is also carrying the roof and ceiling.
How far can a built-up 2x10 floor girder span?
2021 IRC Table R602.7(2) lists a three-ply 2×10 girder in an interior bearing wall carrying one floor at 8’1” in a 24-foot-wide building, with 1 jack stud at each end. Change the ply count, the building width, or the number of floors the girder carries and you are reading a different cell — all of them are on this page. Point loads, cantilevers beyond the table footnotes, unusual snow loads, or anything else outside the table's stated conditions — that's an engineer's question.
What does NJ mean in the header table?
NJ is the number of jack studs the table requires at each end of the header — the studs under the header ends that carry it down to the plate. It is printed in this page as “(2 jacks)” next to the span, and it changes with the size, the load the header supports, the ground snow load, and the building width.
What does 2-2x10 mean in the header table?
It is the number of plies followed by the lumber size. A 2-2×10 header is two 2×10s fastened together; a 3-2×12 is three 2×12s fastened together. Each ply count is its own row, so read the row that matches the header you have.
My ground snow load is under 30 psf — which column applies?
The table’s own instruction is that where the ground snow load is less than 30 psf and the roof live load is 20 psf or less, the 30 psf ground snow columns apply. Confirm the ground snow load for your address with your building department.
Around the header
What the header carries: floor joist spans · ceiling joist spans · rafter spans. What the studs and the header themselves weigh, size by size, is on the lumber weight page.