CONSTRUCTION AND FIRE PROTECTION OF COTTON WAREHOUSES. 31 
For most conditions a floor sufficiently dry will be secured by use 
of the simple concrete pavement first described, provided the propor- 
tion of cement stated is not reduced, the sand is not excessively coarse, 
the stone is of proper size to insure no voids being left open, and 
reasonable care is exercised in mixing and placing the material. 
Floors consisting of a concrete made of a mixture of tar, sand, and 
crushed stone with thick plank embedded upon this layer and the 
surface finished with regular hardwood flooring have been used with 
excellent results. The only objection to this construction is the ex- 
cessive cost, which is prohibitive for the usual warehouse. 
Boards of 2 to 3 inches in thickness may be used laid flat on the 
ground and nailed to skids 4 inches square bedded in the earth. In 
this case the timber should be heart pine or oak. Sap pine may be 
used if air-dried and thoroughly treated with creosote to retard 
decay. Both of these last forms of floor construction are f airly satis- 
factory from a fire-hazard standpoint, though they are not as de- 
sirable as a strictly non-combustible floor such as is afforded by 
concrete. 
Earth, shell, or cinder floors may be used in some sections of the 
country where no damage to the cotton from moisture will occur. As 
a safeguard, however, it usually will be necessary to raise the cotton 
a few inches above this surface by means of wood strips or stringers. 
Such floors make trucking extremely difficult and generally should be 
avoided. 
Upper floors of warehouses several stories in height, should be of 
fire-resistive construction presently to be described. Where there is 
but one floor and the ground is very rolling, there is a temptation to, 
use heavy frame construction. This should not be done, as such con- 
struction reduces the protection against fire very much as far as that 
compartment is concerned. 
Floors of any material and for any conditions, whether there be 
one floor or several stories, should be constructed with a slight incline 
from the center of the compartment toward the exterior wall in order 
that water used in case of fire may drain off readily through wall 
openings or scuppers provided. This slope should be a total of about 
a system of underdraining of the floor. This may be accomplished by placing 
1 foot or more below the floor, a line of open joint field tile, the lines being 
spaced at intervals of from 25 to 50 feet. The trench in which the tile is laid 
should be filled with crushed stone, gravel, broken brick or coarse cinders, while 
still better results are secured when the use of this material is extended to form 
a layer about 2 inches thick under the floor. The lines of tile should be given 
sufficient grade or fall to drain off and discharge water finding its way into 
them. 
