256 ROOF COVERINGS 



free from sand and loam. All walls and openings to be flashed. All 

 roofing cement and tar shall be applied hot. 



In Building Construction and Superintendence, Part II, Kidder 

 gives the following specifications for flashing a gravel roof: 



"Flashing. Finish the roofing against fire walls, chimneys, scuttle 

 and skylight by turning the felt up 4 inches against the wall. Over 

 this lay an 8-inch strip of felt with half its width on the roof. Fasten 

 the upper edge of the strip and the several layers of felt to the wall 

 by laths or wooden strips securely nailed, and press the strip of felt 

 into the angle of the wall and cement to the roof with hot pitch. Nail 

 the lower edge of the strip to the roof every 4 or 5 inches. Take spe- 

 cial care in fitting around chimneys and skylights. Extend the felt up 

 6 inches on the pitch of the roof, and secure every 4 inches with 3d 

 nails with tin washers." 



The pitch should not be more than Y^ and should preferably be 

 about % to I inch to the foot. Gravel is sometimes used on roofs 

 nearly flat. 



Gravel roofing under ordinary conditions will last for from 10 to 

 15 years. -With careful attention it can be made to last longer and has 

 been known to last 30 years. 



The cost of gravel roofing varies with local conditions and speci- 

 fications. In various reports of the Association of Railway Superintend- 

 ents of Bridges and Buildings costs of gravel roofs, not including the 

 sheathing, per square are given as follows: Three-ply gravel roof in 

 California, costs $3.75 ; four-ply (4) gravel roof in Kansas, cos'ts $3.00 ; 

 in Chicago, costs from $3.00 to $4.00; and in New England, costs 

 from $4.00 to $5.00. The cost varies greatly with the specifications. 



Prepared Gravel Roofing. Prepared gravel roofings may be bought 

 in the market. Prepared gravel roofing manufactured by the Armitage 

 Manufacturing Company, Richmond, Va., was quoted at $2.50 per 

 roll of 1 08 square feet and including nails and cement, delivered in cen- 

 tral Illinois. This company has discontinued the manufacture of pre- 

 pared slag roofing. 



Slag Roofing. Slag is sometimes used in the place of gravel in 

 making roofs. The method of constructing the roof and the specifica- 



