CONSTRUCTION NOTES 



355 



desirable to use roofing paper or other paper which will prevent free water 

 from coming in contact with the surface of the tile. (3) (See Plate 149, 

 figure 3.) It may be desirable to leave the water, during the winter, within 

 a deep pool. On the theory that water increases approximately one-eleventh 

 of its volume when transformed into ice it then becomes advisable to anchor 

 barrels or other similar materials on the surface of the pool. During periods 

 of freezing conditions the ice will, under this arrangement, have a tend- 

 ency to heave, and thus the lateral pressure on the walls of the pool will be 

 greatly reduced. 



The main object in the protection of any pool is not to prevent the 

 walls from being subject to freezing conditions, but to prevent the sudden 

 changes of temperature within the area of the pool. These sudden changes 

 of temperature have a tendency to create conditions of expansion and 

 contraction which may prove extremely dangerous to the concrete in the 

 walls and bottom of the pool. 



It is further very desirable to keep outlet drains of any pool open 

 during the entire winter. If a quantity of water is allowed to enter the 



PLATE No. 152 

 PLAN OF WADING POOL, EMERSON WIGHT PLAYGROUND, SPRINGFIELD, MASSACHUSETTS 



This pool was constructed in 1917 at a cost of $1,200, all labor and supervision having been furnished by the 

 Springfield Park Department. The id-inch curb surrounding the pool extends six inches above the water line, 

 and there is an i8-inch surrounding apron sloping two inches from the curb. The basin consists of two inches of 

 trap rock, spaces between which are filled with sand, and which has a gallon of Tarvia X per square yard of surface, 

 making a three-inch impervious bottom. The feed pipes are one inch in diameter. Around the pool is a six-inch 

 pipe drain laid in 48 inches of cinders at a depth of five feet below the curb. The purpose of this is to prevent 

 outside water from reaching the pool bottom. In the central pedestal six inches below the level of the curb, is a 

 drain outlet, and a clean-out drain is placed at the base of the pedestal in a bowl-like depression three inches 

 lower than the pool bottom. Since the maximum depth of this pool is three feet, it is really a wading-swimming pool. 



