WOODEN FLOORS 285 



to 2 inches thick on a cinder foundation 6 inches thick. Fine sand is 

 broomed into the cracks after the brick are in place. 



The cost of this floor per square yard is about as follows : 

 Material. 



Firebox cinders cost nothing $00 . oo 



Paving brick o. 50 



Labor. 



Preparing the foundation 0.20 



Laying the brick '..... 0.15 



Total cost per square yard $o . 85 



Total cost per square foot. 9^ cents. 



The cost of brick floors as given in the reports of the Association 

 of Railway Superintendents of Bridges and Buildings varies from 9^/2 

 to 13 cents per square foot. 



The Southern & Southwestern Railway Club Eng. News, Jan. 16, 

 1896 recommends that round house floors be made of vitrified brick 

 laid as follows : Make a bed surface of slag or chert about 18 inches 

 thick, then put a coat of sand over slag, lay brick on edge and level 

 them up by tamping. After this is done a coat of hot tar is applied 

 which enters the space between the bricks and cements them together. 



Wooden Floors. Coal-tar or asphalt concrete makes the best 

 foundation for a shop floor. If Portland cement is used, the planking 

 will decay very rapidly unless the top of the concrete is mopped with 

 coal-tar or asphalt. A floor laid by Pratt & Whitney Co., of Hartford, 

 Conn., is described as follows : "In laying a basement floor about 18 

 years since of 10,000 square feet, 8,000 square feet were laid over coal- 

 tar and pitch concrete in about equal proportions, and about 2,000 square 

 feet were laid over cement concrete. The latter portion of the floor 

 was removed in about ten years, the timbers and the plank being com- 

 pletely rotted out; while the other was in a perfect state of preserva- 

 toin and has continued so until the present time." The floor with tar 

 concrete foundations was constructed as follows: "Excavation was 

 made about one foot below the floor and six inches of coarse stone 



