DEAINAGE METHODS FOR COUNTY ROADS. 35 



5. After the tile is finished iin<i the forms removed it should be 

 protected from the drying action of the sun and air and kept wet by 

 sprinkling for at least seven days. Then the tile should for about 

 60 days be left in a protected place before it is used. 



6. The cost of concrete tile depends on the cost of the materials 

 of which it is composed and the cost and efficiency of labor. These 

 are so variable in different localities that figures of general value 

 can not be given. In general, the cost of concrete tile probably would 

 average slightly greater for the smaller sizes and slightly less for the 

 larger sizes than that of clay tile. 



LAYING THE TILE. 



In laying the tile work should begin at the lower end of the drain 

 and proceed up hill when bell tile is used, and, in general, the work 

 of excavating, laying and back filling should follow this rule, so 

 that the various steps may be taken and the ditch drained at all 

 times. To insure that the tile is laid true to grade, it is necessary 

 to employ grade stakes, which are usually set by means of an engi- 

 neer's level. These stakes should be spaced about 50 feet apart and 

 offset sufficiently far from the line of the drain not to be disturbed 

 while the ditch is being excavated. The excavation ordinarily is 

 carried down to within a few inches of grade with plows, picks, 

 shovels, etc., and the bottom of the trench is finished with a tile 

 scoop. In handling the scoop great care must be exercised in order 

 to bring the bottom of the ditch to a uniform grade and at the same 

 time scoop out a properly shaped trench to receive the tile. 



The tile should be laid as the ditch is completed, and each section 

 should be turned until the ends fit together closely. Small openings 

 at the joints, due to slight unevenness of the ends, are permissible, 

 provided they are made to come in the bottom of the tile, but any 

 opening more than about :|-inch wide should be covered with a piece 

 of broken tile, cement mortar, or heavy tar paper. In the case of 

 fine sandy soils, all joints should either be wrapped with cloth or 

 tar paper. This is necessary in order to prevent sediment from being 

 carried into the tile. Wherever two drains come together, the junc- 

 tion should be made preferably by means of T or V branches, be- 

 cause, when it is attempted to cut straight sections of tile to fit an 

 angle, one section is very likely to project into the other and cause 

 more or less obstruction. In case it is necessary to use straight tile 

 on curves the joints should be covered with pieces of broken tile. 

 Curves in a tile drain always should be as gradual as the location 

 will permit, and should be avoided if possible. 



As soon as the tile is laid it should be covered carefully to a depth 

 of 5 or 6 inches with loose earth to hold the different sections in 



