60 PRACTICAL SILO CONSTRUCTION 



having a separate form to mold same. The opening 

 is closed by using short lengths of tongued and 

 grooved planks, supplemented with a thickness of 

 tar paper behind same. Two thicknesses of these 

 planks are employed, one at the outside opening of 

 the door, with the other at the opening upon the 

 inside of silo. The latter depends upon the pressure 

 of silage to hold them in place and are placed as 

 the silo is filled. 



The outside planks are held in place by 2x4" 

 strips bolted to the concrete walls, the bolts for same 

 being imbedded in the concrete as the material is 

 placed in form. 



SILO HOOFS 



A successful type of silo roof, using concrete as 

 the covering material, is shown at Fig. 16. The 

 rafters are cut to give the pitch desired, and the 

 roof framed so that a dormer-window or opening is 

 placed upon the side of silo from which it will be 

 filled. The rafters are securely fastened to the wall 

 by bolts imbedded into the concrete of the last 

 course. The " rods used as vertical reinforcement 

 can also be permitted to extend above the last course 

 of concrete and then fitted with threads and a nut so 

 as to bolt the rafter at the foot, cut securely to the wall 

 of silo. The space between rafters is now filled with 

 concrete, flush to the top edge of rafters, and over 

 the top of rafters wire lath, or expanded metal lath, 

 is nailed. This is treated to a plaster coat of con- 



