144 



BULLETIN 414, U. S. DEPAETMEISTT OF AGEICULTUEE. 



from 3 to 6 inches, the larger laps being used on the lower pitches. 

 For the side lap it is recommended that each alternate sheet be laid 

 upside down and lapped as shown in (a) rather than (h), figure 9. By 

 this method, when water is blown through the first lap, it will stop 

 and not pass the haK lap, but run down and out at the end of the 

 sheet. 



In applying to the sheathing or wooden strips, the sheets should be 

 secured by nailing through the tops of the corrugations, the nails 

 being driven through every alternate corrugation at the ends and 

 about 8 inches apart at the sides. 



In ordering corrugated sheets an allowance must be made for the 

 laps. The following table (17) gives the number of square feet 



Fig. 9. — Proper (a) and improper (b) manner of laying corrugated roofing. 



necessary to cover 100 square feet of actual surface, using sheets 8 

 feet long. If shorter sheets are used, the allowance must be slightly 

 increased. 



Table 17. — Nuviber of square feet of corrugated sheets to cover 100 square feet of roof . 



End laps. 



1 incli. 



2 inclies. 



3 inclies. 



4 inclies. 



5 inches. 



Square 



Square. 



Square 



Square 



Square 



feet. 



feet. 



feet. 



feet. 



feet. 



110 



Ill 



112 



113 



114 



116 



117 



118 



119 



120 



123 



124 



125 



126 



127 



6 inches. 



Side lap, one corrugation 



Side lap, one and one-half corrugations . 

 Side lap, two corrugations 



Square 

 feet. 

 115 

 121 

 128 



Cement Concrete. 



Portland cement concrete may be used in a convict camp for vari- 

 ous purposes, such as the construction of floors, building foundations, 

 well casings, and protective coverings, etc. Necessary information 



yr^ 



TSBT 



'TT 



