2×10 ceiling joist spans (2021 IRC)
Every allowable span the 2021 International Residential Code ceiling tables list for a 2×10 joist — four species, four grades, four spacings, both attic load cases — each table cited where it sits.
2021 IRC Table R802.5.1(2) covers uninhabitable attics with limited storage; 2021 IRC Table R802.5.1(1) covers uninhabitable attics without storage. Both tables are below, in that order.
A 2×10 Southern pine No. 2 ceiling joist at 16-inch centers spans up to 18’1” in an uninhabitable attic with limited storage (2021 IRC Table R802.5.1(2)). Widen the spacing to 24-inch centers and the same joist is listed at 14’9”; hold 16-inch centers and switch to Spruce-pine-fir No. 2 and the table lists 19’10”. Under 2021 IRC Table R802.5.1(1) — uninhabitable attics without storage, 10 psf live / 5 psf dead / L/240 — that same Southern pine No. 2 at 16 inches is listed at 25’7”.
2×10 ceiling joists — uninhabitable attics with limited storage
| 2×10 — species and grade | 12" on center | 16" on center | 19.2" on center | 24" on center |
|---|---|---|---|---|
| Douglas fir-larch Select Structural | 26’+ | 25’0” | 23’7” | 21’3” |
| Douglas fir-larch No. 1 | 24’6” | 21’3” | 19’5” | 17’4” |
| Douglas fir-larch No. 2 | 23’3” | 20’2” | 18’5” | 16’5” |
| Douglas fir-larch No. 3 | 17’9” | 15’5” | 14’1” | 12’7” |
| Hem-fir Select Structural | 26’+ | 23’8” | 22’3” | 20’6” |
| Hem-fir No. 1 | 24’3” | 21’0” | 19’2” | 17’1” |
| Hem-fir No. 2 | 22’7” | 19’7” | 17’10” | 16’0” |
| Hem-fir No. 3 | 17’4” | 15’0” | 13’8” | 12’3” |
| Southern pine Select Structural | 26’+ | 24’7” | 23’1” | 21’6” |
| Southern pine No. 1 | 24’0” | 20’9” | 18’11” | 16’11” |
| Southern pine No. 2 | 20’11” | 18’1” | 16’6” | 14’9” |
| Southern pine No. 3 | 16’1” | 14’0” | 12’9” | 11’5” |
| Spruce-pine-fir Select Structural | 25’5” | 23’1” | 21’8” | 19’5” |
| Spruce-pine-fir No. 1 | 22’11” | 19’10” | 18’2” | 16’3” |
| Spruce-pine-fir No. 2 | 22’11” | 19’10” | 18’2” | 16’3” |
| Spruce-pine-fir No. 3 | 17’4” | 15’0” | 13’8” | 12’3” |
2021 IRC Table R802.5.1(2) — uninhabitable attics with limited storage, 20 psf live / 10 psf dead / L/240. table source
2×10 ceiling joists — uninhabitable attics without storage
| 2×10 — species and grade | 12" on center | 16" on center | 19.2" on center | 24" on center |
|---|---|---|---|---|
| Douglas fir-larch Select Structural | 26’+ | 26’+ | 26’+ | 26’+ |
| Douglas fir-larch No. 1 | 26’+ | 26’+ | 26’+ | 24’6” |
| Douglas fir-larch No. 2 | 26’+ | 26’+ | 26’0” | 23’3” |
| Douglas fir-larch No. 3 | 25’2” | 21’9” | 19’10” | 17’9” |
| Hem-fir Select Structural | 26’+ | 26’+ | 26’+ | 26’+ |
| Hem-fir No. 1 | 26’+ | 26’+ | 26’+ | 24’3” |
| Hem-fir No. 2 | 26’+ | 26’+ | 25’3” | 22’7” |
| Hem-fir No. 3 | 24’6” | 21’3” | 19’5” | 17’4” |
| Southern pine Select Structural | 26’+ | 26’+ | 26’+ | 26’+ |
| Southern pine No. 1 | 26’+ | 26’+ | 26’+ | 24’0” |
| Southern pine No. 2 | 26’+ | 25’7” | 23’5” | 20’11” |
| Southern pine No. 3 | 22’9” | 19’9” | 18’0” | 16’1” |
| Spruce-pine-fir Select Structural | 26’+ | 26’+ | 26’+ | 25’5” |
| Spruce-pine-fir No. 1 | 26’+ | 26’+ | 25’8” | 22’11” |
| Spruce-pine-fir No. 2 | 26’+ | 26’+ | 25’8” | 22’11” |
| Spruce-pine-fir No. 3 | 24’6” | 21’3” | 19’5” | 17’4” |
2021 IRC Table R802.5.1(1) — uninhabitable attics without storage, 10 psf live / 5 psf dead / L/240. table source
The two attic cases
2021 IRC Table R802.5.1(1) is the uninhabitable attics without storage case: 10 psf live over 5 psf dead, L/240. 2021 IRC Table R802.5.1(2) is the uninhabitable attics with limited storage case: 20 psf live over 10 psf dead, L/240. The dead load is the part that gets skipped — 5 psf where the attic holds no storage, 10 psf where the table allows limited storage — and it is why the same 2×10 carries two different spans on this page.
Each number is the span the code table lists for that species, grade, and on-center spacing at the load case stamped at the top of this page. Change the spacing, the grade, or the species and you are reading a different cell of the same table.
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.
Other sizes and assemblies
Other ceiling joist sizes: 2×4 ceiling joists · 2×6 ceiling joists · 2×8 ceiling joists
The same 2×10 in other assemblies: 2×10 floor joists · 2×10 rafters · 2×10 deck joists
Common questions
Can 2×10 ceiling joists span 21 feet?
At 16-inch centers, 2×10 Southern pine No. 2 is listed at 18’1” in 2021 IRC Table R802.5.1(2) (20 psf live / 10 psf dead / L/240). 23 of the 64 2×10 cells in that table are 21 feet or longer, and the widest spacing among them is 24-inch centers — Douglas fir-larch Select Structural at 24 inches is listed at 21’3”.
Do these 2×10 ceiling joist spans allow attic storage?
Two cases, two tables. 2021 IRC Table R802.5.1(1) is the uninhabitable attics without storage case — 10 psf live over 5 psf dead at L/240 — and lists 2×10 Southern pine No. 2 at 16-inch centers at 25’7”. 2021 IRC Table R802.5.1(2) is the uninhabitable attics with limited storage case — 20 psf live over 10 psf dead at L/240 — and lists the same joist at 18’1”.
How far can a 2×10 ceiling joist span at 24-inch centers?
2021 IRC Table R802.5.1(2) — uninhabitable attics with limited storage — lists 2×10 No. 2 at 24-inch centers as Douglas fir-larch 16’5”, Hem-fir 16’0”, Southern pine 14’9”, Spruce-pine-fir 16’3”. The same four in 2021 IRC Table R802.5.1(1) (uninhabitable attics without storage): 23’3”, 22’7”, 20’11”, 22’11”.