Drain and vent lines are important aspects of your home's sewer system. We'll show you why they matter and how to install them yourself.
Installing drain and vent lines in your bathroom is a home project that can be completed in a weekend. Before you begin, have your plans approved by an inspector and consider the following:
- Drain and vent lines must be positioned precisely, so you should install them before the supply pipes. It may be possible to simplify supply runs by moving a vent pipe over a few inches.
- If you must run drainpipes across a floor, carefully calculate the amount of vertical space available; you must slope the drainpipe at 1/8 to 1/4 inch drop per foot.
- Sometimes it's difficult to visualize how drainpipes will travel through walls and floors. Once you start assembling the pieces and testing them for fit, you may need to modify your plans.
- Some inspectors prefer horizontal vent pipes to be sloped so condensation can run back to the drainpipes; others don't consider this important. To be on the safe side, slope the vents.
Before you begin, check your plumbing setup. A joist may be in the way of a toilet bend. If so, remove as much flooring as necessary to get at the framing. Cut the joist, install a blocking piece, and attach 2x4 cleats around the opening.