EXCAVATION. 



Excavation for the foundation of the building 

 shall be carried dov;n to solid earth. The bottom of the ex- 

 oavation shall be level and smooth. When necessary to 

 grade into unlevel ground for the purpose of providing a 

 level building site, the slopes of the excavations result- 

 ing must clear tho sides of the building by at least 3 feet. 

 If necessary, provision should be made to prevent earth cav- 

 ing from the embankment from contacting with the Bills. If 

 posts are of wood, they too should be protected. 



FOUNDATION. 



Do not place foundation blocks or underpinning 

 further apart than 6 inches on center. Where snow loads 

 are excessive or where the ground is not firm, place the 

 foundation blocks or underpinning on 4 foot centers under 

 all outside sills and on 6 foot centers under all interior 

 sills. 



Foundations should be either of - 



(a) 6" x 6" heart cedar, redwood or Douglas fir under- 

 pinning, set unon substantial flat stones of sufficient 

 thickness to project at least 4 inches nbove the ground. 

 Wood blocks should never be used for footings under founda- 

 tion posts. 



(b) If substantial stones are not available, a masonry 

 footing should be provided. For masonry use only hard 

 stones, preferebly fiat ones. All should be carefully im- 

 bedded on their broadest faces in mortar of 1 part cement and 

 2 parts coarse, clean, sharp sand. Each layer should be 

 well filled and flushed up on both sides and firmly bonded 

 together. The tops should be made level to receive the 

 underpinning. See Table No. C-4. 



(c) Large stones of sufficient thickness to raise the 

 sill to a height of at least 12 inches above the ground. 



(d) Blocks of masonry or concrete et least 12 inches 

 high, 10 inches wide on top and 16 inches square at the bottom. 

 The top of concrete and masonry blocks should be made level 



to receive the sills. See Concrete Section and Table No. C-4. 



