Ceiling joist span tables (2021 IRC)

Both ceiling joist tables the 2021 International Residential Code publishes, in full: 2021 IRC Table R802.5.1(1) for uninhabitable attics without storage and 2021 IRC Table R802.5.1(2) for uninhabitable attics with limited storage. Every size, every species, every grade, every on-center spacing — each table cited where it sits, with a link down to the page for each size.

20 psf live / 10 psf dead / L/240 10 psf live / 5 psf dead / L/240

20 psf live / 10 psf dead / L/240

12’0”

Per 2021 IRC Table R802.5.1(2) — uninhabitable attics with limited storage, 20 psf live / 10 psf dead / L/240.

A 2×6 Southern pine No. 2 ceiling joist at 16-inch centers spans up to 12’0” in an attic with limited storage (2021 IRC Table R802.5.1(2)). Take the storage away and 2021 IRC Table R802.5.1(1) — 10 psf live / 5 psf dead / L/240 — lists the same joist at 16’11”.

Which of the two tables applies

The two ceiling tables differ in what the attic above is used for. 2021 IRC Table R802.5.1(1) is uninhabitable attics without storage at 10 psf live / 5 psf dead / L/240. 2021 IRC Table R802.5.1(2) is uninhabitable attics with limited storage at 20 psf live / 10 psf dead / L/240 — double the live load and double the dead load. Both ceiling tables hold deflection to L/240; the floor tables hold L/360.

Neither table is a floor. Both are labeled uninhabitable attics, and neither covers a habitable room — for a room's floor, even one tucked under a roof, see the floor joist span tables. 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.

The common case, size by size

No. 2 grade at 16-inch centers in an attic with limited storage, across the 4 species 2021 IRC Table R802.5.1(2) lists. Each size links to its own page, where the full table for that size sits alongside the without-storage table.

Joist size	Douglas fir-larch	Hem-fir	Southern pine	Spruce-pine-fir
2×4 ceiling joists	8’11”	8’4”	8’0”	8’7”
2×6 ceiling joists	13’0”	12’8”	12’0”	12’10”
2×8 ceiling joists	16’6”	16’0”	15’3”	16’3”
2×10 ceiling joists	20’2”	19’7”	18’1”	19’10”

2021 IRC Table R802.5.1(2) — uninhabitable attics with limited storage, 20 psf live / 10 psf dead / L/240, No. 2 grade at 16-inch centers. table source

Uninhabitable attics with limited storage — the full table

2021 IRC Table R802.5.1(2), every size the table covers. Spacing runs across the top; species and grade run down the side; the blocks are the lumber sizes. Cells that read 26’+ are spans the table lists as exceeding 26 feet.

Species and grade	12" on center	16" on center	19.2" on center	24" on center
2×4 ceiling joists
Douglas fir-larch Select Structural	10’5”	9’6”	8’11”	8’3”
Douglas fir-larch No. 1	10’0”	9’1”	8’7”	7’8”
Douglas fir-larch No. 2	9’10”	8’11”	8’2”	7’3”
Douglas fir-larch No. 3	7’10”	6’10”	6’2”	5’7”
Hem-fir Select Structural	9’10”	8’11”	8’5”	7’10”
Hem-fir No. 1	9’8”	8’9”	8’3”	7’7”
Hem-fir No. 2	9’2”	8’4”	7’10”	7’1”
Hem-fir No. 3	7’8”	6’8”	6’1”	5’5”
Southern pine Select Structural	10’3”	9’4”	8’9”	8’1”
Southern pine No. 1	9’10”	8’11”	8’5”	7’8”
Southern pine No. 2	9’3”	8’0”	7’4”	6’7”
Southern pine No. 3	7’2”	6’2”	5’8”	5’1”
Spruce-pine-fir Select Structural	9’8”	8’9”	8’3”	7’8”
Spruce-pine-fir No. 1	9’5”	8’7”	8’0”	7’2”
Spruce-pine-fir No. 2	9’5”	8’7”	8’0”	7’2”
Spruce-pine-fir No. 3	7’8”	6’8”	6’1”	5’5”
2×6 ceiling joists
Douglas fir-larch Select Structural	16’4”	14’11”	14’0”	13’0”
Douglas fir-larch No. 1	15’9”	13’9”	12’6”	11’2”
Douglas fir-larch No. 2	15’0”	13’0”	11’11”	10’8”
Douglas fir-larch No. 3	11’6”	9’11”	9’1”	8’1”
Hem-fir Select Structural	15’6”	14’1”	13’3”	12’3”
Hem-fir No. 1	15’2”	13’7”	12’4”	11’1”
Hem-fir No. 2	14’5”	12’8”	11’7”	10’4”
Hem-fir No. 3	11’2”	9’8”	8’10”	7’11”
Southern pine Select Structural	16’1”	14’7”	13’9”	12’9”
Southern pine No. 1	15’6”	14’0”	12’9”	11’5”
Southern pine No. 2	13’11”	12’0”	11’0”	9’10”
Southern pine No. 3	10’6”	9’2”	8’4”	7’5”
Spruce-pine-fir Select Structural	15’2”	13’9”	12’11”	12’0”
Spruce-pine-fir No. 1	14’9”	12’10”	11’9”	10’6”
Spruce-pine-fir No. 2	14’9”	12’10”	11’9”	10’6”
Spruce-pine-fir No. 3	11’2”	9’8”	8’10”	7’11”
2×8 ceiling joists
Douglas fir-larch Select Structural	21’7”	19’7”	18’5”	17’2”
Douglas fir-larch No. 1	20’1”	17’5”	15’10”	14’2”
Douglas fir-larch No. 2	19’1”	16’6”	15’1”	13’6”
Douglas fir-larch No. 3	14’7”	12’7”	11’6”	10’3”
Hem-fir Select Structural	20’5”	18’6”	17’5”	16’2”
Hem-fir No. 1	19’10”	17’2”	15’8”	14’0”
Hem-fir No. 2	18’6”	16’0”	14’8”	13’1”
Hem-fir No. 3	14’2”	12’4”	11’3”	10’0”
Southern pine Select Structural	21’2”	19’3”	18’2”	16’10”
Southern pine No. 1	20’5”	17’9”	16’2”	14’6”
Southern pine No. 2	17’7”	15’3”	13’11”	12’6”
Southern pine No. 3	13’3”	11’6”	10’6”	9’5”
Spruce-pine-fir Select Structural	19’11”	18’1”	17’1”	15’10”
Spruce-pine-fir No. 1	18’9”	16’3”	14’10”	13’3”
Spruce-pine-fir No. 2	18’9”	16’3”	14’10”	13’3”
Spruce-pine-fir No. 3	14’2”	12’4”	11’3”	10’0”
2×10 ceiling joists
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

Uninhabitable attics without storage — the full table

2021 IRC Table R802.5.1(1), on the 10 psf live / 5 psf dead / L/240 basis, every size the table covers. Across the 256 cells the two tables share, 2021 IRC Table R802.5.1(1) lists a longer span than 2021 IRC Table R802.5.1(2) in 253 of them and the same span in 3 — never a shorter one. More of its cells also run past the 26-foot end of the table: 36 of 256, against 3 of 256 in 2021 IRC Table R802.5.1(2).

Species and grade	12" on center	16" on center	19.2" on center	24" on center
2×4 ceiling joists
Douglas fir-larch Select Structural	13’2”	11’11”	11’3”	10’5”
Douglas fir-larch No. 1	12’8”	11’6”	10’10”	10’0”
Douglas fir-larch No. 2	12’5”	11’3”	10’7”	9’10”
Douglas fir-larch No. 3	11’1”	9’7”	8’9”	7’10”
Hem-fir Select Structural	12’5”	11’3”	10’7”	9’10”
Hem-fir No. 1	12’2”	11’0”	10’4”	9’8”
Hem-fir No. 2	11’7”	10’6”	9’11”	9’2”
Hem-fir No. 3	10’10”	9’5”	8’7”	7’8”
Southern pine Select Structural	12’11”	11’9”	11’0”	10’3”
Southern pine No. 1	12’5”	11’3”	10’7”	9’10”
Southern pine No. 2	11’10”	10’9”	10’2”	9’3”
Southern pine No. 3	10’1”	8’9”	8’0”	7’2”
Spruce-pine-fir Select Structural	12’2”	11’0”	10’4”	9’8”
Spruce-pine-fir No. 1	11’10”	10’9”	10’2”	9’5”
Spruce-pine-fir No. 2	11’10”	10’9”	10’2”	9’5”
Spruce-pine-fir No. 3	10’10”	9’5”	8’7”	7’8”
2×6 ceiling joists
Douglas fir-larch Select Structural	20’8”	18’9”	17’8”	16’4”
Douglas fir-larch No. 1	19’11”	18’1”	17’0”	15’9”
Douglas fir-larch No. 2	19’6”	17’8”	16’8”	15’0”
Douglas fir-larch No. 3	16’3”	14’1”	12’10”	11’6”
Hem-fir Select Structural	19’6”	17’8”	16’8”	15’6”
Hem-fir No. 1	19’1”	17’4”	16’4”	15’2”
Hem-fir No. 2	18’2”	16’6”	15’7”	14’5”
Hem-fir No. 3	15’10”	13’9”	12’6”	11’2”
Southern pine Select Structural	20’3”	18’5”	17’4”	16’1”
Southern pine No. 1	19’6”	17’8”	16’8”	15’6”
Southern pine No. 2	18’8”	16’11”	15’7”	13’11”
Southern pine No. 3	14’11”	12’11”	11’9”	10’6”
Spruce-pine-fir Select Structural	19’1”	17’4”	16’4”	15’2”
Spruce-pine-fir No. 1	18’8”	16’11”	15’11”	14’9”
Spruce-pine-fir No. 2	18’8”	16’11”	15’11”	14’9”
Spruce-pine-fir No. 3	15’10”	13’9”	12’6”	11’2”
2×8 ceiling joists
Douglas fir-larch Select Structural	26’+	24’8”	23’3”	21’7”
Douglas fir-larch No. 1	26’+	23’10”	22’5”	20’1”
Douglas fir-larch No. 2	25’8”	23’4”	21’4”	19’1”
Douglas fir-larch No. 3	20’7”	17’10”	16’3”	14’7”
Hem-fir Select Structural	25’8”	23’4”	21’11”	20’5”
Hem-fir No. 1	25’2”	22’10”	21’6”	19’10”
Hem-fir No. 2	24’0”	21’9”	20’6”	18’6”
Hem-fir No. 3	20’1”	17’5”	15’10”	14’2”
Southern pine Select Structural	26’+	24’3”	22’10”	21’2”
Southern pine No. 1	25’8”	23’10”	22’0”	20’5”
Southern pine No. 2	24’7”	21’7”	19’8”	17’7”
Southern pine No. 3	18’9”	16’3”	14’10”	13’3”
Spruce-pine-fir Select Structural	25’2”	22’10”	21’6”	19’11”
Spruce-pine-fir No. 1	24’7”	22’4”	21’0”	18’9”
Spruce-pine-fir No. 2	24’7”	22’4”	21’0”	18’9”
Spruce-pine-fir No. 3	20’1”	17’5”	15’10”	14’2”
2×10 ceiling joists
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

Common questions

Which ceiling joist table applies — attic with storage or without?

2021 IRC Table R802.5.1(1) covers uninhabitable attics without storage at 10 psf live / 5 psf dead / L/240; 2021 IRC Table R802.5.1(2) covers uninhabitable attics with limited storage at 20 psf live / 10 psf dead / L/240. The storage case carries twice the live load and twice the dead load. For the same 2×6 Southern pine No. 2 joist at 16-inch centers, the two tables list 16’11” without storage and 12’0” with limited storage.

How far can a ceiling joist span?

For Southern pine No. 2 at 16-inch centers in an attic with limited storage (2021 IRC Table R802.5.1(2)), the table lists 2×4 8’0”, 2×6 12’0”, 2×8 15’3”, 2×10 18’1”. Without storage (2021 IRC Table R802.5.1(1)) the same joists are listed at 2×4 10’9”, 2×6 16’11”, 2×8 21’7”, 2×10 25’7”.

How far apart are ceiling joists?

At one of the 4 on-center spacings both ceiling tables list: 12, 16, 19.2 or 24 inches, measured center to center. The spacing is chosen along with the size, species and grade, and it moves the span — a 2×6 Southern pine No. 2 joist in an attic with limited storage (2021 IRC Table R802.5.1(2)) is listed at 13’11” at 12-inch centers, 12’0” at 16-inch centers, 11’0” at 19.2-inch centers, 9’10” at 24-inch centers. Neither table lists a spacing wider than 24 inches.

How much weight can a ceiling joist hold?

Neither ceiling table states a weight a joist can hold. Each states the design load its spans were worked for, per square foot of ceiling: 2021 IRC Table R802.5.1(1), uninhabitable attics without storage, carries 10 psf live load and 5 psf dead load; 2021 IRC Table R802.5.1(2), uninhabitable attics with limited storage, carries 20 psf live and 10 psf dead; both hold deflection to L/240. A cell is an answer only inside those loads. A floor for a room, heavier storage, or a load hung from one spot is outside both tables. 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.

Why do so many ceiling joist cells read 26 feet or more?

Both ceiling tables stop at 26 feet: where the span would run past that, the code prints a note instead of a number, and this site prints 26’+ for those cells. 36 of the 256 cells in 2021 IRC Table R802.5.1(1) are listed that way, against 3 of 256 in 2021 IRC Table R802.5.1(2). A cell that reads 26’+ is not a longer span you can claim — it is past what the table covers. 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.

Do these tables cover a habitable attic room?

No. Both tables on this page are labeled uninhabitable attics — one without storage, one with limited storage. Neither is a habitable room. For a habitable room's floor, the floor joist tables (2021 IRC Table R502.3.1(1) and 2021 IRC Table R502.3.1(2)) are the ones to read. Local codes amend these tables and your inspector has the final word — confirm with your building department.

The rest of the framing

Ceiling joist sizes: 2×4 ceiling joists · 2×6 ceiling joists · 2×8 ceiling joists · 2×10 ceiling joists

Other assemblies: floor joist span tables · rafter span tables · deck joist span tables · deck beam spans · header and girder spans

Local codes amend these tables and your inspector has the final word — confirm with your building department.