FOUNDATION AND ROOF TYPES. 



97 



Foundations. Concrete 

 block silos require heavier 

 foundation footings than do 

 clay block or wooden silos. 

 They should not be less 

 than 28 inches wide at the 

 bottom and 2 feet deep. 

 A mixture of one part ce- 

 ment, three parts sand, and 

 six parts broken stone or 

 course gravel will make a 

 mixture for the footings and 

 foundation walls. 



Fig. 40. Two types of foun- 

 dation for cement block 

 silos. Courtesy Nebraska 

 Station. 



The Roof. Figure 41 illustrates 

 the cornice work and forms for a 

 concrete roof to correspond in per- Fig. 41. Illustrating how 



manence and fire-proof qualities 

 with the remainder of the silo. A 

 one-third pitch is recommended. 



to build cornice f or con- 

 crete roof on a concrete 

 block silo ._ Courtesy Ne . 



braska Station. 



Patented Reinforcements. The weak point in any sectional 

 block construction is in the joints between the blocks and the 

 attempts to overcome this are demonstrated in many forms 

 of patented reinforced cement blocks now being used for 

 silo building. Where the blocks are made of a poured or gravity 

 mixture, using the best quality of cement, sand and gravel ob- 

 tainable, they are extremely dense and strong. One of these, 

 known as the Hurst System, uses blocks 24x12x4 inches thick. 

 Running laterally through each block are two % inch round 



