56 MANAGEMENT OF DAIRY PLANTS 



3. Cork. Cork is perhaps one of the most satisfactory ma- 

 terials for both efficiency and durability. It is used in the form 

 of granulated cork and also as cork slabs. Slabs are put on in 

 one or more courses, in the latter case all joints being broken. 



In accordance with instructions given by a constructing firm 

 the cork board should be erected in a half-inch Portland cement 

 mortar mixed in the proportion of one part Portland cement 

 to two parts clean, sharp sand. Against the exposed surface of 

 this cork board, a Portland cement plaster finish, about ^ inch 

 in thickness, is applied in two coats. The first coat is approxi- 

 mately y inch in thickness, mixed in the proportion stated 

 above, and rough scratched; the second coat is approximately 

 y inch in thickness, mixed in the proportion of one part Port- 

 land cement to one and one-half parts of clean, sharp sand, 

 and brought to a finish with a steel trowel. The plaster should 

 be kept wet by daily sprinkling for at least a week after the 

 second coat is applied, in order to reduce cracking to a 

 minimum. 



The ceiling and floor are insulated in a manner similar to 

 the wall. The cork boards should fit closely together at the 

 corners (see Fig. n). The floor, if a ground floor, should be 

 dug down to such depth that, after the insulating material has 

 been applied, it will be level with other floors in the building. 

 Such a floor may be constructed as follows: After the ground 

 has been properly graded, cinders to the depth of about 4 inches 

 or more may be added. These are thoroughly packed and on 

 them is placed about 4 inches of concrete. On top of this the 

 cork boards are laid so as to join with the cork boards of the 

 walls. The floor is finished by adding about 4 inches of con- 

 crete on top of the cork and then about % inch of finishing 

 cement, as in laying any other cement floor. 



4. Mineral Wool. Mineral wool is made from the slag of 

 blast furnaces. It will absorb moisture; but aside from that, 

 it meets the requirements of an efficient insulating material. 

 It is now furnished in slabs as the most convenient form for 

 use. In this form it may be put on walls in the same manner 

 as cork slabs; but, not being waterproof, it is usually put on 



