Building
Trap Replacement
What is a Building Trap?
It is easy to find many older properties that still have a building trap in place. This device is attached to the main drain of a household’s sewer drain, it serves to stop sewage gases and water backflow from entering the home. If your home or property was built before the 1960-70s, you most likely have a building trap (unless you’ve already had it replaced). This type of trap is also referred to as a sewer trap, sanitary trap, or a running trap.
The building trap is a U-bend clay pipe that builders would install on the exterior sewer line of houses built before the use of modern plumbing fittings. The purpose of the trip was to stop odorous gases entering the home from the sewer, and it worked by “trapping” a small amount of water in the bend – just like the S-bend under your kitchen sink does. You can check whether your home has a building trap by searching in your front garden for a cast iron “cap” in the shape of a mushroom. It’s usually located on a pipe close to the surface.
