ROOFING 253 



pure linseed oil is recommended. The under side of the sheets should 

 be painted before laying. Tin roofs should be painted every two or 

 three years. If kept well painted a tin roof should last 25 to 30 years. 



For flat seam roofing, using *^>-inch locks, a box of 14 x 20 tin 

 will cover 192 square feet, and for standing seam, using ^-inch locks 

 and turning ij4 and 1^2 -inch edges, making i-inch standing seams, it 

 will lay 1 68 square feet. For flat seam roofing, using 3/2 -inch locks, 

 a box of 20 x 28 tin will lay about 399 square feet, and for standing 

 seam, using ^-inch locks and turning ij4 and i^-inch edges, making 

 I -inch standing seams, it will lay about 365 square feet. 



Current prices in 1903 for tin in small quantities were about as 

 follows : 



American Charcoal Plates: 



1C, 14x20 $5. 50 to $6. 50 per box of 112 sheets; 



IX, 14 x 20 $6 . 60 to $8 . 25 per box of 1 12 sheets. 



American Coke Plates, Bessemer : 



1C, 14 x 20 $4.70 to $4.80 per box of 112 sheets ; 



IX, 14 x 20 $6.60 to $8.25 per box of 112 sheets. 



American Terne Plates: 



1C, 20x28 $ 9.50; 



IX, 20x28 $11.50. 



Two good workmen can put on and paint from 2^2 to 3 squares 

 of tin roofing in 8 hours. Tin roofs cost from $7.00 to $11.00 or 

 $12.00 per square depending upon the specifications and the cost of 

 labor. 



Sheet Steel Roofing. Sheet steel roofing is sold in sheets 28 

 inches wide and from 4 to 12 feet long, or in rolls 26 inches wide and 

 about 50 feet long. It is commonly laid with vertical standing seams 

 and horizontal flat seams; tin cleats from 12 to 15 inches apart being 

 nailed to the plank sheathing and locked into the seams. Sheet steel 

 plates are also made with standing crimped seams near the edges, which 

 are nailed to V-shaped sticks ; the horizontal seams being made by 

 lapping about 6 inches. 



