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BULLETIN 1141, U. S. DEPARTMEXT OF AGRICULTURE. 



of the workroom floor. If the ground upon which the building 

 stands is firm and dry the earth itself may form the floor of the 

 furnace room. If the location or soil is such that trouble from 

 seepage is to be expected, the furnace room should be floored with a 

 layer of concrete resting upon broken stone. 



Walls. — The walls of most of the dry kilns are constructed of 

 wood. Concrete, concrete blocks, hollow tile, brick, or stone makes 

 a more durable structure, but the first cost is considerably higher. 

 Wood kilns demand frequent repairs, are short lived, and take a 

 higher rate of insurance than kilns made of other material. The 

 most economical material to use must be determined by local condi- 



Fig. 1. — Cross section and ground plan of a kiln. When the kilns are built in rows the 

 furnace rooms are not separated, but the furnaces have separate inclosures and hoppers 

 for distributing the heat. The drying floors are separated by walls. 



tions; if concrete is cheap in a particular locality, that may be the 

 best material. The details of the construction of the kiln must be 

 determined by the material used for the walls, but the interior di- 

 mensions remain the same irrespective of the kind of material se- 

 lected. In the usual type of wood construction, the walls are made 

 by setting 2 by 6 inch studding 16 inches apart, measured center to 

 center. On the outside of the studding a layer of sheathing boards 

 is placed diagonally. A layer of building paper is then applied, and 

 the siding placed on the outside of this. When cement blocks are 

 used, the wall, as a rule, is made 8 inches thick. The same dimension 

 is used for hollow tile or brick. When stone is used, the walls must 

 be 10 to 12 inches thick. Whatever the material used, the doors, 



