The pipe should be laid on the bottom of the trench to a pitch of at least 1⁄4 inch per foot fall. In laying, the start should be made at the street sewer with hubs of pipe toward the building. The trench should be dug within a few inches of the bottom of the pipe, then as the pipe is laid the exact depth is dug out, the surplus dirt being thrown on the pipe already laid. The body length of pipe should be on solid foundation. A space dug out for each hub as shown in Fig. 38 allows for this, also allows for the proper cementing of joints. To get the proper pitch of pipe, take for example 1⁄4 inch per foot, a level 2 feet long with a piece of wood or metal on one end 1⁄2 inch thick will answer. The end with the 1⁄2-inch piece on should be on the lower hub and the other end resting on the hub of the pipe about to be put in place. When the bubble shows level, then the pipe has the 1⁄4-inch fall per foot. If a tile trap is used, it should be laid level, otherwise the seal will be weakened or entirely broken.

Fig. 38.  Laying terra cotta pipe. Fig. 38. - Laying terra-cotta pipe.

Cutting

The cutting of tile is not difficult, but must be done carefully or the pipe will crack or a piece will be broken out, thus making the pipe worthless. To cut tile or terra-cotta pipe, stand the pipe on end with the hub down, fill the pipe with sand to the point of cutting. With a sharp chisel and hammer cut around the pipe two or three times and the pipe will crack around practically straight.

Cementing

If the pipe is free from cracks, the only possible way roots can get into the inside of terra-cotta pipe is through the cement joint. There are two ways of making these joints. Both ways are explained below and are used today on terra-cotta work.

  1. First

    The bottom of the hub of pipe in place is filled with cement and the straight end of the next piece of pipe is laid in place, then more cement is placed into the hub until the space between the hub and the pipe is filled. In a trench, a trowel is rather unhandy to work with, while the hands can be used to better advantage. The cement can be forced into place with the hands and then surfaced with a trowel. The rest of the operation is to swab out the inside joint to remove any cement that perchance was forced through the joint (see Fig. 39). The cement used should be 1⁄2 cement and 1⁄2 clean sharp sand.

    Second

    Half of the space between the hub and the pipe is first packed with oakum and then the other half filled with cement of the same proportions as that used above.

Fig. 39.  Showing use of the swab. Fig. 39. - Showing use of the swab.