Plumbing Under The Floor

How to cut a concrete floor for new plumbing.

Plumbing under the floor.

Supply leaks under the kitchen sink or bath vanity can go unnoticed for a long time since they re usually at the back of the cabinet. Diameter vertical pipe that runs into the basement floor. But it may run at an angle rather than straight out to the street. From there the pipe runs under the floor and out to the city sewage system under the street.

Also notice the drain is centered right in the middle of this 30 inch vanity. So before you can do any real planning you have to find that line. The photo below shows a sink drain hot water line and cold water line at a stud wall on the outer edge of the floor slab. The holes must follow a straight line across the floor and must ascend or descend so the pipe will be sloped 1 4 inch per foot.

Water can run down the pipes into the floor or subfloor rotting the sink base the floor and the framing. The two major plumbing codes in the united states is the ipc international plumbing code and the upc. The plumbing trenches are typically dug at the same time as the slab footings if any. Using the dimensions on the floor plan measure from the outside of the foundation walls or slab.

First locate the main stack the large 3 or 4 in. If joists are 16 inches on center and pipes run across them at a right angle holes should differ in height by about 3 8 inch. Take your floor plan and measuring tape and check the location of every pipe. The center of the lav s drain is located 18 approximately above the finished floor.

Once the trenches are dug you can add the sewer pipes and stub outs pipes that sit above the slab floor that eventually connect the sink toilet bathtub or shower and any other drains to the system.