HOWTO: Slab Leak Repair

Slab leak repair, while tedious, does not have to be as dreaded as it usually is. Homes with no basement or crawl space are built on a concrete slab. Some plumbing elements, such as the pipes, are located underneath the slab foundation. This makes it very difficult to repair a leak in a pipe under the slab. This usually happens to the hot water pipe, due to the fluctuation in temperature of the pipe. If your water or electric bill is higher than usual, you might have a hot water leak.

If you do have a hot water leak, the best way to find it is to take your shoes and socks off and walk around your house, feeling the temperature of the floor. (It is a good idea to pick up any rugs as well.) When you find a part of the floor that is unusually warm, you have found your hot water leak. Note or mark this area so you know where you need to work.

To start with, you must remove the flooring from the area. This can be done with a saw or chisel/crowbar and hammer, or just by pulling it up if you have a linoleum floor. Try to remove only as much as you need to, however. The less you pull up, the less you will have to replace when you are done fixing the leak.

Once you have removed the flooring, try to pinpoint exactly where the leak is and use a concrete drill bit to drill down through the slab. Slab foundations are usually about 4 inches thick so it may take some time. Make a hole you can fit your hand through, and feel around for the leak. Once you have located it, you can make a bigger hole in the slab so you have better access while you work on it.

Shut off your water at the water main before you do any work on the pipes. After you have done this, it is safe to cut the pipe. Cut out the leaky area of pipe and replace it with identical pipe. If you have PVC pipe, make sure you cut out at least six inches on either side of the leak to make sure there are no smaller cracks around the larger one. Then simply replace the length of pipe, sealing it well. If you have copper piping, you will have to weld the pipes together. If this is the case, you should leave the hole open for a couple of days after the repair, just to make sure everything is sealed properly.

To finish your slab leak repair, you have to seal the hole and replace your flooring. Sealing the hole back up is simple: mix a bag of concrete and fill the hole to the top. As with any concrete, it is best to let it cure for several days. Then you can re-floor the hole you made, using whatever method was originally used. Congratulations- you have repaired your leak.