3o8 



ENGINEERING ON THE FARM 



Galvanized iron is made of mild steel or of ingot iron. Iron 

 costs about one-half more than steel. 



Brick. Bricks are sold by the thousand. Brick work is 

 measured and calculated on the basis of a superficial foot of 

 finished wall. 



Number of Brick Required per Square Foot of 

 Surface Where a %-Inch Mortar Joint Is Used 



Bricks per 

 Thickness of Wall Square Foot 



8- or 9-inch 15 



12- or 13-inch 22^ 



16- or 1 7-inch 3° 



4- or 43^-inch additional wall 73^ 



No allowance is made for openings of less than 80 square 



feet. 



One man can lay 60 pressed brick per hour, or 120 to 175 

 common brick. Ordinarily one helper is provided for each 

 bricklayer, but on thin walls where pressed brick is used, 

 one helper for each two bricklayers is sufficient. 



To lay 1,000 common brick, it requires one barrel of lime 

 (which is equivalent to 3 bushels) together with ^i yard 

 of sand. If cement mortar is used, i}4 barrels of cement 

 and H yard of sand are required. This makes a 1 to 3H 



mixture. It is difficult to 

 lay brick in pure cement 

 mortar. For this reason 

 it is common to use a 

 cement lime mortar in 

 the proportion of 1 lime, 

 2 cement, and 6 sand. 

 This requires 3 bushels 

 of lime, i}4 barrels of 

 cement, and ^ yard 

 of sand. Pressed brick 

 require less mortar than the more irregular shapes. A 

 colored joint in brick work costs about $1.00 per 

 thousand extra. 



Tread 



Fig. 250. 



Jui f/oor ' 

 Stairway, using rabbited 



risers 



