Page 119 - 2018_IRC

FOUNDATIONS

TABLE R403.1(3)
MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS
WITH CAST-IN-PLACE CONCRETE OR FULLY GROUTED MASONRY WALL CONSTRUCTION (inches) a, b
SNOW LOAD LOAD-BEARING VALUE OF SOIL
STORY AND TYPE
OR ROOF LIVE OF STRUCTURE WITH CMU (psf)
LOAD 1500 2000 2500 3000 3500 4000
1 story—slab-on-grade 14  6 1 2  6 12  6 1 2  6 12  6 1 2  6
1 story—with crawl space 19  6 14  6 12  6 1 2  6 12  6 1 2  6
1 story—plus basement 25  8 19  6 15  6 13  6 12  6 1 2  6
2 story—slab-on-grade 23  7 18  6 14  6 1 2  6 12  6 1 2  6
20 psf 2 story—with crawl space 35  12 22  6 17  6 14  6 12  15  6 6 1 13  6
29  9

 6
2
2 story—plus basement
26  8
21  6
17  6
3 story—slab-on-grade 32 11 24  7 19  6 16  6 14  6 1 2  6
3 story—with crawl space 38  14 28  9 23  6 19  6 16  6 14  6
3 story—plus basement 43  17 33  11 26  8 22  6 19  6 16  6
1 story—slab-on-grade 15  6 1 2  6 12  6 1 2  6 12  6 1 2  6
1 story—with crawl space 20  6 15  6 12  6 1 2  6 12  6 1 2  6
1 story—plus basement 26  8 20  6 16  6 13  6 12  6 1 2  6
2 story—slab-on-grade 24  7 18  6 15  6 1 2  6 12  6 1 2  6
30 psf 2 story—with crawl space 30  10 22  6 18  6 15  6 13  15  6 6 1 13  6
 6
2

18  6
36  13
27  8
2 story—plus basement
21  6
3 story—slab-on-grade 33  12 25  7 20  6 17  6 14  6 1 2  6
3 story—with crawl space 39  14 29  9 23  7 19  6 17  6 14  6
3 story—plus basement 44  17 33  12 27 8 22  6 19  6 17  6
1 story—slab-on-grade 17  6 13  6 12  6 1 2  6 12  6 1 2  6
1 story—with crawl space 22  6 17  6 13  6 1 2  6 12  6 1 2  6
1 story—plus basement 28 9 21  6 17  6 14  6 12  6 1 2  6
2 story—slab-on-grade 27  8 20  6 16  6 13  6 12  6 1 2  6
50 psf 2 story—with crawl space 32  11 24  7 19  6 16  6 14  16  6 6 1 14  6
2
 6

38  14
19  6
2 story—plus basement
28  9
23  6
3 story—slab-on-grade 35  13 27  8 21  6 18  6 15  6 13  6
3 story—with crawl space 41  15 31  10 24  7 20  6 17  6 15  6
3 story—plus basement 47  18 35  12 28  9 23  7 20  6 17  6
1 story—slab-on-grade 19  6 14  6 12  6 1 2  6 12  6 1 2  6
1 story—with crawl space 25  7 18  6 15  6 1 2  6 12  6 1 2  6
1 story—plus basement 30  10 23  6 18  6 15  6 13  6 1 2  6
2 story—slab-on-grade 29  9 22  6 17  6 14  6 12  6 1 2  6
70 psf 2 story—with crawl space 34  12 30  10 21  6 17  6 15  6 13  6
26  8
20  6
40  15
15  6
17  6
2 story—plus basement
24  7
3 story—slab-on-grade 38  14 28  9 23  6 19  6 16  6 14  6
3 story—with crawl space 43  16 32  11 26  8 21  6 18  6 16  6
3 story—plus basement 49  19 37  13 29  10 24  7 21  6 18  6
2
For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m .
a. Interpolation allowed. Extrapolation is not allowed.
b. Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width
of the house add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

SLAB CRAWL BASEMENT
ON GRADE SPACE

94 2018 INTERNATIONAL RESIDENTIAL CODE ®
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