30 MANAGEMENT OF DAIRY PLANTS 



2. Sione and Tile. — If sawed stone or tile is used for the 

 floor, either one should be laid in cement on a concrete base 

 similar to the base constructed for cement floors. 



3. Asphalt. — This has been used for creamery floors to some 

 extent as a surface coating usually of about one and one half 

 inches in thickness. It is laid on a concrete base as in the case 

 of floors previously described. As asphalt floor has the advan- 

 tage of being comparatively soft and hence less tiring to work- 

 men than the harder floors. Furthermore, it is considered 

 waterproof, and is comparatively easy to repair. However, as 

 it gradually dissolves under hot water, it proves less desirable 

 for floor covering in a creamery. 



4. Plank. — The plank floor was formerly used more exten- 

 sively than any other kind. As it is unsanitary and lacking 

 in durability, it cannot be considered very serviceable. 



FOUNDATIONS, WALLS, AND BRICKWORK 



Mortar. — Kidder ^ recommends for brickwork a mortar 

 made from one part of Portland cement and three parts of 

 sand. "One barrel of Portland cement and three barrels of 

 sand thoroughly and properly mixed will make 31/3 barrels, or 

 12 cubic feet, of good strong mortar . . . sufiicient to 

 lay . . . 750 bricks, with 1/4 to 3/8-inch joints." 



Hoeppner maintains that a mortar made from cement and 

 sand alone should not be used for hollow tile, as such mortar 

 is too "short" and will roll off the tile and hence does not insure 

 a full joint. 



Cement. — Cement used for building construction should 

 meet the following requirements of the American Society for 

 Testing Materials: 



The specific gravity of the cement, thoroughly dried at 100° 

 C, shall not be less than 3.10. 



It shall leave by weight a residue of not more than 8 per cent 

 on a No. 100, and not more than 25 per cent on a No. 200 sieve. 



It shall develop initial set in not less than thirty minutes, 



' Architects' and Builders' Pocketbook, by Kidder, 1912, pp. 19(^200. 



