LOADS IN STRUCTURES 



(51 



WEIGHT OF BUILDING MATERIALS PER SQUARE FOOT 



(Continued) 



Name of Material 



'Average 

 Weight 

 Pounds 



Per 



Square 

 Foot 



Neponset roofing felt, two layers 



Spruce sheathing, 1 in. thick , 



i in. thick 1.81 



A in. thick 2.71 



1 in. thick 3.62 



Slate, single thickness f in. thick 5.43 



\ in. thick 7.25 



I in. thick 9.06 



f in. thick 10.87 



Shingles, common, 6 in. X 18 in., 5 in. to weather. 2 



Skylight of glass, ^ to J in., including frame .... 4 to 10 



Slag roof, four-ply. 4 



Steel roofing, standing seam , . 1 



Tiles, Spanish, 14$ in. X 10} in., 7i in. to weather 8} 

 Tiles, plain, 10} in. XGJ in. Xf in., 5i in. to 



weather 18 



White-pine sheathing, 1 in. thick 2 



Yellow-pine sheathing, 1 in. thick 



Gravel roof and four-ply felt 5} 



Gravel roof and five-ply felt 



Roofing, three-ply ready (asphalt, rubberoid, 



etc.) 6 to 10 



Purlins, wooden, with 12- to 16-ft. span 2 



Chestnut or maple sheathing, 1 in. thick 4 



Ash, hickory, or oak sheathing, 1 in. thick 5 



Sheet iron, A in. thick 3 



Thatch. . . 6.5 



LIVE LOADS 



If the live load consists of heavy material, such as mer- 

 chandise in a warehouse, and if the amount of this material 

 and its location are known, the live load is usually calculated 

 from the table of weights of materials given on pages 64-81. 

 If, however, the structure is to be used as a dwelling, a hotel, 



