WAC 51-51-0403 Section R403 -- Footings.

R403.1 General. All exterior walls shall be supported on continuous solid or fully grouted masonry or concrete footings, wood foundations, or other approved structural systems which shall be of sufficient design to accommodate all loads specified in Section R301 and to transmit the resulting loads to the supporting soil within the limitations determined from the characteristics of the soil. Footings shall be supported on undisturbed natural soil or engineered fill. Foundation walls complying with Section R404 or stem walls complying with Section R403.1.3 shall be permitted to support exterior walls, exterior braced wall lines and exterior braced wall panels provided they are supported by continuous footings.

TABLE R403.1

MINIMUM WIDTH OF CONCRETE,

PRECAST OR MASONRY FOOTINGS

(inches)

	LOAD-BEARING VALUE OF SOIL (psf)
	1,500	2,000	3,000	≥4,000
Conventional light-frame construction
1 floor^b,c	12	12	12	12
2 floors^b,c	15	12	12	12
3 floors^b,c	23	17	12	12
4-inch brick veneer over light frame or 8-inch hollow concrete masonry
1-story	12	12	12	12
2-story	21	16	12	12
3-story	32	24	16	12
8-inch solid or fully grouted masonry
1-story	16	12	12	12
2-story	29	21	14	12
3-story	42	32	21	16

For SI:	1 inch = 25.4 mm, 1 pound per square foot = 0.0479kPa.
	a. Where minimum footing width is 12 inches, use of a single wythe of solid or fully grouted 12-inch nominal concrete masonry units is permitted.
	b. Represents the number of floors supported.
	c. Footings shall be permitted to support a roof in addition to the stipulated number of floors. Footings supporting a roof only shall be as required for supporting one floor.

R403.1.2 Continuous Footing in Seismic Design Categories D₀, D₁ and D₂. The braced wall panels at exterior walls of buildings located in Seismic Design Categories D₀, D₁ and D₂ shall be supported by continuous footings. All required interior braced wall panels shall be supported on footings at intervals not exceeding 50 feet (15,240 mm).

Figure 403.4(1). Note corrected title and labels:

�� BASEMENT OR CRAWL SPACE WITH PRECAST CONCRETE FOUNDATION WALL BEARING ON CRUSHED STONE

�� PRECAST CONCRETE FOUNDATION WALL

�� CRUSHED STONE FOOTING

Figure 403.4(2). Note corrected title and label:

�� BASEMENT OR CRAWL SPACE WITH PRECAST CONCRETE FOUNDATION WALL ON SPREAD FOOTING

�� PRECAST CONCRETE FOUNDATION WALL

[Statutory Authority: Chapter 19.27 RCW. 10-24-061, � 51-51-0403, filed 11/29/10, effective 7/1/11. Statutory Authority: RCW 19.27.031 and 19.27.074. 10-03-098, � 51-51-0403, filed 1/20/10, effective 7/1/10. Statutory Authority: RCW 19.27.190, 19.27.020, and chapters 19.27 and 34.05 RCW. 08-01-103, � 51-51-0403, filed 12/18/07, effective 4/1/08. Statutory Authority: RCW 19.27.074, 19.27.020, and chapters 19.27 and 34.05 RCW. 07-01-090, � 51-51-0403, filed 12/19/06, effective 7/1/07.]