6 foot centers under all exterior sills and girts. Where 

 underpinning on short centers are necessary, add sufficient 

 material to the lumber order list to provide for them. 



Foundations should be either of - 



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

 pinning, set upon substantial flat stones of sufficient 

 thickness to project at least 4 inches above 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, preferably flat 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 at least 12 inches 

 high, 10 inches wide on top and 16 inches square at; the bot- 

 tom. The top of concrete and masonry blocks should : be made 

 level to receive the sills. See Concrete Section and Table 

 No, C-4. 



MATERIALS. 



All structural materials should conform as closely 

 as possible to the specifications given in the builder's 

 list and lumber order list. That minor deviations must 

 sometimes be made is recognized as unavoidable. 



SILLS. 



Should preferably be of cedar or redwood. Douglas 

 fir may be used as a second cho*ice. 



.- . ' i '.' . 



Rectangular sills should be laid'with ? the narrow 

 face up. 



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