ICC Subscriptions
 
R502.3.1 Sleeping areas and attic joists. Table R502.3.1(1) shall be used to determine the maximum allowable span of floor joists that support sleeping areas and attics that are accessed by means of a fixed stairway in accordance with Section R311.7 provided that the design live load does not exceed 30 pounds per square foot (1.44 kPa) and the design dead load does not exceed 20 pounds per square foot (0.96 kPa). The allowable span of ceiling joists that support attics used for limited storage or no storage shall be determined in accordance with Section R802.4.

TABLE R502.3.1(1) FLOOR JOIST SPANS FOR COMMON LUMBER SPECIES

(Residential sleeping areas, live load = 30 psf, L/Δ = 360)a


JOIST SPACING (inches)
SPECIES AND GRADE
DEAD LOAD = 10 psf
DEAD LOAD = 20 psf
2×6
2×8
2×10
2×12
2×6
2×8
2×10
2×12
Maximum floor joist spans
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
  Douglas fir-larch SS
12-6
16-6
21-0
25-7
12-6
16-6
21-0
25-7
  Douglas fir-larch #1
12-0
15-10
20-3
24-8
12-0
15-7
19-0
22-0
  Douglas fir-larch #2
11-10
15-7
19-10
23-0
11-6
14-7
17-9
20-7
  Douglas fir-larch #3
9-8
12-4
15-0
17-5
8-8
11-0
13-5
15-7
  Hem-fir SS
11-10
15-7
19-10
24-2
11-10
15-7
19-10
24-2
  Hem-fir #1
11-7
15-3
19-5
23-7
11-7
15-2
18-6
21-6
  Hem-fir #2
11-0
14-6
18-6
22-6
11-0
14-4
17-6
20-4
12
Hem-fir #3
9-8
12-4
15-0
17-5
8-8
11-0
13-5
15-7
  Southern pine SS
12-3
16-2
20-8
25-1
12-3
16-2
20-8
25-1
  Southern pine #1
12-0
15-10
20-3
24-8
12-0
15-10
20-3
24-8
  Southern pine #2
11-10
15-7
19-10
24-2
11-10
15-7
18-7
21-9
  Southern pine #3
10-5
13-3
15-8
18-8
9-4
11-11
14-0
16-8
  Spruce-pine-fir SS
11-7
15-3
19-5
23-7
11-7
15-3
19-5
23-7
  Spruce-pine-fir #1
11-3
14-11
19-0
23-0
11-3
14-7
17-9
20-7
  Spruce-pine-fir #2
11-3
14-11
19-0
23-0
11-3
14-7
17-9
20-7
  Spruce-pine-fir #3
9-8
12-4
15-0
17-5
8-8
11-0
13-5
15-7
  Douglas fir-larch SS
11-4
15-0
19-1
23-3
11-4
15-0
19-1
23-0
  Douglas fir-larch #1
10-11
14-5
18-5
21-4
10-8
13-6
16-5
19-1
  Douglas fir-larch #2
10-9
14-1
17-2
19-11
9-11
12-7
15-5
17-10
  Douglas fir-larch #3
8-5
10-8
13-0
15-1
7-6
9-6
11-8
13-6
  Hem-fir SS
10-9
14-2
18-0
21-11
10-9
14-2
18-0
21-11
  Hem-fir #1
10-6
13-10
17-8
20-9
10-4
13-1
16-0
18-7
  Hem-fir #2
10-0
13-2
16-10
19-8
9-10
12-5
15-2
17-7
16
Hem-fir #3
8-5
10-8
13-0
15-1
7-6
9-6
11-8
13-6
  Southern pine SS
11-2
14-8
18-9
22-10
11-2
14-8
18-9
22-10
  Southern pine #1
10-11
14-5
18-5
22-5
10-11
14-5
17-11
21-4
  Southern pine #2
10-9
14-2
18-0
21-1
10-5
13-6
16-1
18-10
  Southern pine #3
9-0
11-6
13-7
16-2
8-1
10-3
12-2
14-6
  Spruce-pine-fir SS
10-6
13-10
17-8
21-6
10-6
13-10
17-8
21-4
  Spruce-pine-fir #1
10-3
13-6
17-2
19-11
9-11
12-7
15-5
17-10
  Spruce-pine-fir #2
10-3
13-6
17-2
19-11
9-11
12-7
15-5
17-10
  Spruce-pine-fir #3
8-5
10-8
13-0
15-1
7-6
9-6
11-8
13-6
  Douglas fir-larch SS
10-8
14-1
18-0
21-10
10-8
14-1
18-0
21-0
  Douglas fir-larch #1
10-4
13-7
16-9
19-6
9-8
12-4
15-0
17-5
  Douglas fir-larch #2
10-1
12-10
15-8
18-3
9-1
11-6
14-1
16-3
  Douglas fir-larch #3
7-8
9-9
11-10
13-9
6-10
8-8
10-7
12-4
  Hem-fir SS
10-1
13-4
17-0
20-8
10-1
13-4
17-0
20-7
  Hem-fir #1
9-10
13-0
16-4
19-0
9-6
12-0
14-8
17-0
  Hem-fir #2
9-5
12-5
15-6
17-1
8-11
11-4
13-10
16-1
19.2
Hem-fir #3
7-8
9-9
11-10
13-9
6-10
8-8
10-7
12-4
  Southern pine SS
10-6
13-10
17-8
21-6
10-6
13-10
17-8
21-6
  Southern pine #1
10-4
13-7
17-4
21-1
10-4
13-7
16-4
19-6
  Southern pine #2
10-1
13-4
16-5
19-3
9-6
12-4
14-8
17-2
  Southern pine #3
8-3
10-6
12-5
14-9
7-4
9-5
11-1
13-2
  Spruce-pine-fir SS
9-10
13-0
16-7
20-2
9-10
13-0
16-7
19-6
  Spruce-pine-fir #1
9-8
12-9
15-8
18-3
9-1
11-6
14-1
16-3
  Spruce-pine-fir #2
9-8
12-9
15-8
18-3
9-1
11-6
14-1
16-3
  Spruce-pine-fir #3
7-8
9-9
11-10
13-9
6-10
8-8
10-7
12-4
  Douglas fir-larch SS
9-11
13-1
16-8
20-3
9-11
13-1
16-2
18-9
  Douglas fir-larch #1
9-7
12-4
15-0
17-5
8-8
11-0
13-5
15-7
  Douglas fir-larch #2
9-1
11-6
14-1
16-3
8-1
10-3
12-7
14-7
  Douglas fir-larch #3
6-10
8-8
10-7
12-4
6-2
7-9
9-6
11-0
  Hem-fir SS
9-4
12-4
15-9
19-2
9-4
12-4
15-9
18-5
  Hem-fir #1
9-2
12-0
14-8
17-0
8-6
10-9
13-1
15-2
  Hem-fir #2
8-9
11-4
13-10
16-1
8-0
10-2
12-5
14-4
24
Hem-fir #3
6-10
8-8
10-7
12-4
6-2
7-9
9-6
11-0
  Southern pine SS
9-9
12-10
16-5
19-11
9-9
12-10
16-5
19-11
  Southern pine #1
9-7
12-7
16-1
19-6
9-7
12-4
14-7
17-5
  Southern pine #2
9-4
12-4
14-8
17-2
8-6
11-0
13-1
15-5
  Southern pine #3
7-4
9-5
11-1
13-2
6-7
8-5
9-11
11-10
  Spruce-pine-fir SS
9-2
12-1
15-5
18-9
9-2
12-1
15-0
17-5
  Spruce-pine-fir #1
8-11
11-6
14-1
16-3
8-1
10-3
12-7
14-7
  Spruce-pine-fir #2
8-11
11-6
14-1
16-3
8-1
10-3
12-7
14-7
  Spruce-pine-fir #3
6-10
8-8
10-7
12-4
6-2
7-9
9-6
11-0


For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
 
Note: Check sources for availability of lumber in lengths greater than 20 feet.
 
a. Dead load limits for townhouses in Seismic Design Category C and all structures in Seismic Design Categories D0, D1 and D2 shall be determined in accordance with Section R301.2.2.2.1.


TABLE R502.3.1(2) FLOOR JOIST SPANS FOR COMMON LUMBER SPECIES

(Residential living areas, live load = 40 psf, L/Δ = 360)b 


JOIST SPACING (inches)
SPECIES AND GRADE
DEAD LOAD = 10 psf
DEAD LOAD = 20 psf
2×6
2×8
2×10
2×12
2×6
2×8
2×10
2×12
Maximum floor joist spans
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
(ft - in.)
  Douglas fir-larch SS
11-4
15-0
19-1
23-3
11-4
15-0
19-1
23-3
  Douglas fir-larch #1
10-11
14-5
18-5
22-0
10-11
14-2
17-4
20-1
  Douglas fir-larch #2
10-9
14-2
17-9
20-7
10-6
13-3
16-3
18-10
  Douglas fir-larch #3
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
  Hem-fir SS
10-9
14-2
18-0
21-11
10-9
14-2
18-0
21-11
  Hem-fir #1
10-6
13-10
17-8
21-6
10-6
13-10
16-11
19-7
  Hem-fir #2
10-0
13-2
16-10
20-4
10-0
13-1
16-0
18-6
12
Hem-fir #3
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
  Southern pine SS
11-2
14-8
18-9
22-10
11-2
14-8
18-9
22-10
  Southern pine #1
10-11
14-5
18-5
22-5
10-11
14-5
18-5
22-5
  Southern pine #2
10-9
14-2
18-0
21-9
10-9
14-2
16-11
19-10
  Southern pine #3
9-4
11-11
14-0
16-8
8-6
10-10
12-10
15-3
  Spruce-pine-fir SS
10-6
13-10
17-8
21-6
10-6
13-10
17-8
21-6
  Spruce-pine-fir #1
10-3
13-6
17-3
20-7
10-3
13-3
16-3
18-10
  Spruce-pine-fir #2
10-3
13-6
17-3
20-7
10-3
13-3
16-3
18-10
  Spruce-pine-fir #3
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
  Douglas fir-larch SS
10-4
13-7
17-4
21-1
10-4
13-7
17-4
21-0
  Douglas fir-larch #1
9-11
13-1
16-5
19-1
9-8
12-4
15-0
17-5
  Douglas fir-larch #2
9-9
12-7
15-5
17-10
9-1
11-6
14-1
16-3
  Douglas fir-larch #3
7-6
9-6
11-8
13-6
6-10
8-8
10-7
12-4
  Hem-fir SS
9-9
12-10
16-5
19-11
9-9
12-10
16-5
19-11
  Hem-fir #1
9-6
12-7
16-0
18-7
9-6
12-0
14-8
17-0
  Hem-fir #2
9-1
12-0
15-2
17-7
8-11
11-4
13-10
16-1
16
Hem-fir #3
7-6
9-6
11-8
13-6
6-10
8-8
10-7
12-4
  Southern pine SS
10-2
13-4
17-0
20-9
10-2
13-4
17-0
20-9
  Southern pine #1
9-11
13-1
16-9
20-4
9-11
13-1
16-4
19-6
  Southern pine #2
9-9
12-10
16-1
18-10
9-6
12-4
14-8
17-2
  Southern pine #3
8-1
10-3
12-2
14-6
7-4
9-5
11-1
13-2
  Spruce-pine-fir SS
9-6
12-7
16-0
19-6
9-6
12-7
16-0
19-6
  Spruce-pine-fir #1
9-4
12-3
15-5
17-10
9-1
11-6
14-1
16-3
  Spruce-pine-fir #2
9-4
12-3
15-5
17-10
9-1
11-6
14-1
16-3
  Spruce-pine-fir #3
7-6
9-6
11-8
13-6
6-10
8-8
10-7
12-4
  Douglas fir-larch SS
9-8
12-10
16-4
19-10
9-8
12-10
16-4
19-2
  Douglas fir-larch #1
9-4
12-4
15-0
17-5
8-10
11-3
13-8
15-11
  Douglas fir-larch #2
9-1
11-6
14-1
16-3
8-3
10-6
12-10
14-10
  Douglas fir-larch #3
6-10
8-8
10-7
12-4
6-3
7-11
9-8
11-3
  Hem-fir SS
9-2
12-1
15-5
18-9
9-2
12-1
15-5
18-9
  Hem-fir #1
9-0
11-10
14-8
17-0
8-8
10-11
13-4
15-6
  Hem-fir #2
8-7
11-3
13-10
16-1
8-2
10-4
12-8
14-8
19.2
Hem-fir #3
6-10
8-8
10-7
12-4
6-3
7-11
9-8
11-3
  Southern pine SS
9-6
12-7
16-0
19-6
9-6
12-7
16-0
19-6
  Southern pine #1
9-4
12-4
15-9
19-2
9-4
12-4
14-11
17-9
  Southern pine #2
9-2
12-1
14-8
17-2
8-8
11-3
13-5
15-8
  Southern pine #3
7-4
9-5
11-1
13-2
6-9
8-7
10-1
12-1
  Spruce-pine-fir SS
9-0
11-10
15-1
18-4
9-0
11-10
15-1
17-9
  Spruce-pine-fir #
8-9
11-6
14-1
16-3
8-3
10-6
12-10
14-10
  Spruce-pine-fir #2
8-9
11-6
14-1
16-3
8-3
10-6
12-10
14-10
  Spruce-pine-fir #3
6-10
8-8
10-7
12-4
6-3
7-11
9-8
11-3
  Douglas fir-larch SS
9-0
11-11
15-2
18-5
9-0
11-11
14-9
17-1
  Douglas fir-larch #1
8-8
11-0
13-5
15-7
7-11
10-0
12-3
14-3
  Douglas fir-larch #2
8-1
10-3
12-7
14-7
7-5
9-5
11-6
13-4
  Douglas fir-larch #3
6-2
7-9
9-6
11-0
5-7
7-1
8-8
10-1
  Hem-fir SS
8-6
11-3
14-4
17-5
8-6
11-3
14-4
16-10a
  Hem-fir #1
8-4
10-9
13-1
15-2
7-9
9-9
11-11
13-10
  Hem-fir #2
7-11
10-2
12-5
14-4
7-4
9-3
11-4
13-1
24
Hem-fir #3
6-2
7-9
9-6
11-0
5-7
7-1
8-8
10-1
  Southern pine SS
8-10
11-8
14-11
18-1
8-10
11-8
14-11
18-1
  Southern pine #1
8-8
11-5
14-7
17-5
8-8
11-3
13-4
15-11
  Southern pine #2
8-6
11-0
13-1
15-5
7-9
10-0
12-0
14-0
  Southern pine #3
6-7
8-5
9-11
11-10
6-0
7-8
9-1
10-9
  Spruce-pine-fir SS
8-4
11-0
14-0
17-0
8-4
11-0
13-8
15-11
  Spruce-pine-fir #1
8-1
10-3
12-7
14-7
7-5
9-5
11-6
13-4
  Spruce-pine-fir #2
8-1
10-3
12-7
14-7
7-5
9-5
11-6
13-4
  Spruce-pine-fir #3
6-2
7-9
9-6
11-0
5-7
7-1
8-8
10-1


For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

Note:
Check sources for availability of lumber in lengths greater than 20 feet.

a. End bearing length shall be increased to 2 inches.

b. Dead load limits for townhouses in Seismic Design Category C and all structures in Seismic Design Categories D0, D1, and D2 shall be determined in accordance with Section R301.2.2.2.1.