BUILDING CONSTRUCTION 143 



hustled to and from a building. A smooth impervious floor is 

 not dangerous if it is kept clean and if the animals are not hurried 

 or frightened. 



For both economic and hygienic reasons a floor must be durable. 

 One that has been badly laid wears unevenly and subsides in patches. 

 If made of concrete on an unsatisfactory foundation it cracks and 

 wears into holes, which give lodgment to water and dirt and are a 

 constant nuisance. 



For a floor to be free from damp it is necessary that it be at 

 least 6 inches above the surrounding ground. Should, however, 

 the ground be so sloping that the floor must of necessity be below 

 the level of the outside at any part, then provision must be 

 made for keeping out the damp by the formation of a " dry 

 area " or a special damp-proof course. If the floor is on the 

 same level or below the outside ground it is always difficult to keep 

 out the damp, and the doorways in wet weather are invariably wet 

 and dirty. A low-level floor is much more difficult to drain than 

 one that is raised. 



Of the materials commonly used for the flooring of animal- 

 houses, cement concrete is undoubtedly the best. If properly laid 

 and of good composition it is as durable as any other flooring, 

 more impervious than most, and relatively as cheap. The bottom- 

 ing of a floor is the same whatever material is used to cover it, 

 and since the durability and, consequently, the hygienic condition 

 of the floor depend very largely upon the nature of the bottoming, 

 particular attention is paid to it. 



To ensure a satisfactory and lasting floor the earth must be 

 cleared away to the necessary depth, which will vary with the nature 

 of the soil, levelled off and well rammed until it presents a hard, 

 even surface. Having prepared the ground, a layer of stones or 

 bricks broken to pass through a 4-inch ring is then spread to a depth 

 of 5 or 6 inches, rammed compactly and finished to a proper level 

 on top. It is important that this foundation should be well con- 

 structed, for if badly laid it causes the floor to sink and crack. On 

 this bottoming is laid a 3 or 4-inch thick cement concrete floor, 

 composed of one part Portland cement, four parts gravel, broken 

 stones or bricks and two parts sand, the whole being well mixed 

 together with clean water. The concrete is then well beaten down, 

 levelled off with a wooden float, which leaves a slightly rough 

 surface, and left to set. It may be brushed with a stiff brush after 

 it is levelled to give a somewhat rougher face. In order to give 

 additional foothold, the cement concrete may be grooved in straight 

 lines, herring-bone fashion, or checkered (see fig. 57). The grooves 



