SPECIFICATIONS FOR RESERVOIR WATERPROOFING After the first layer of concrete has become set and is perfectly dry, all dust must be carefully brushed off; and on this dry, clean surface, and also in joints between blocks, shall be applied, with ordinary paint brushes, one heavy coat of primer paint, manufactured by (or any paint equal thereto). Over eachjoint in concrete, there shall be placed a single layer of asphalt-saturated wool felt, not less than 8 inches in width, which felt shall be laid in hot voir waterproofing asphalt (or any asphalt equal thereto), which asphalt shall be heated to a temperature of be tween 425°F. and 450°F. On the primed surface, and also over the strips of felt, shall be mopped a heavy coat ing of the hot asphalt, which coating must be of uniform thickness of one-eighth of an inch.
The above specification applies to side walls, bottom, and ends of reservoir. After the waterproofing asphalt has cooled, the next layer of concrete is to be laid over it as provided herein. No asphalt need be applied in the joints of the second layer of concrete, as this layer is simply to protect the waterproofing asphalt.
In reservoir waterproofing, some of the spe cial waterproofing compounds are frequently used, either alone or in combination with asphalt. Very frequently no special provisions are made except that of special care in the mix ing and placing of the concrete. The degree of water-tightness to be attained governs the method to be adopted. It will be desirable to back the reservoir walls with twelve to fifteen inches of clay puddle.
The design of the floor is a most important item in reservoir construction. For small reser voirs it is desirable to put in a floor monolithic with the walls, and to reinforce it in both direc tions for temperature and shrinkage cracks. In larger work it is customary to place the floor upon a layer of clay puddle—the concrete being separated into blocks for its full depth, and the joints run with hot asphalt filler.