16 PRACTICAL SILO CONSTRUCTION 



water-proofing the silo. In ordinary practise two or 

 three thin coats of this material applied over the 

 walls will be ample water-proofing for the purpose, 

 as this brush coat fills the pores of the concrete in 

 an effective manner. Caution must be observed 

 in using this brush coat, that it is not applied too 

 thick, as then it will craze or check, thus supplying 

 cracks for the admission of moisture. By having it 

 quite thin, and brushing well when spreading, the 

 purpose is accomplished with two coats, successfully 

 filling the pores but not applying more material than 

 will perfectly bond with the concrete in the wall. 



The thickness of wall does not prevent the free- 

 zing of the silage, for concrete, as with stone ma- 

 sonry, is not frost-proof in any ordinary thickness 

 as employed for walls. The most successful method 

 to avoid freezing of the silage is to build double 

 walls to the silo, with an air-chamber between same. 

 This is accomplished in the block construction and 

 also in the monolithic type of construction. While 

 freezing is not an injury to the silage, the protection 

 of a double wall against same is a positive preventa- 

 tive against this annoyance in feeding a feature 

 that is of value in our cold winters of the Northern 

 States. 



The double wall silo with sealed air-chambers is 

 also an assurance against the danger of air reaching 

 the silage, as well as moisture penetrating the walls. 



