DIY Toilet Drain Vents

Toilet drain vents are necessary to the proper functioning of any toilet. A toilet drain vent runs from the toilet base to the roof of the home, where it stands open so that air can enter and exit freely. Without the free movement of air in drain vents, toilets may bubble, make noises, overflow and even empty without warning or cause. Air pressure equalizes the water pressure inside your toilet drain system; the vent is the doorway through which this air flows. Installation of a toilet drain vent requires both carpentry and plumbing skills, and some specialized tools.

Rubber pipe adapter, 3 inch to 1 1/2 inch
Pipe wrench
Screwdriver
PVC pipe, 1 1/2 inch
Double female PVC adapters, 1 1/2 inch
PVC pipe cleaning solution
PVC pipe cement
Hacksaw
Power drill
Hole cutter
Razor knife
Double female PVC adapter, 1 1/2 inch to 3 inch
Rubber roof sealer

Instructions

- 1
  Locate the vertical sewer main into which your toilet drains. The pipe should be a minimum of 3 inches in diameter and will likely be cast iron or PVC. Inspect the area above the main to ensure there is enough space to run an extension to the roof of the building.
- 2
  Install a 3-inch to 1 1/2-inch rubber adapter to the top end of the sewer main. The main will typically be topped by an end cap. Use your pipe wrench to remove the cap. Slide the larger end of the adapter over the open main end, and use your screwdriver to tighten the metal hose clamp, which is provided.
- 3
  Slide a length of 1 1/2-inch-diameter PVC pipe into the open end of the rubber adapter, and use your screwdriver to tighten the other hose clamp until both joints are firmly fastened. Extend the 1 1/2-inch pipe upward through the structure until it reaches the roof. Add 1 1/2-inch double female adapters and lengths of pipe as needed to make up the distance.
- 4
  Install each PVC adapter by first applying PVC pipe cleaner to the inside rim of the adapter and the outside rim of the pipe to which it is being attached. Allow the cleaner to dry, then apply PVC cement in the same locations, and slide the two together. Hold the joint for a few moments, and allow it to dry according to the manufacturer's instructions. Repeat the cementing process with each pipe or adapter you add, and use your hacksaw to cut the pipes to fit.
- 5
  Use your power drill and a hole-cutter bit to make a 3-inch-diameter hole through the roof from the bottom up. On the top side, use a razor knife to cut away any tiles that remain over the hole.
- 6
  Convert the portion of your vent pipe which exits through the wall or roof from 1 1/2 inch back to 3 inches in diameter. Install a 1 1/2-to-3-inch double female PVC adapter to the top end of the drain vent pipe, about 12 inches below the underside of the roof. Install a final length of 3-inch PVC pipe into the adapter and through the surface of the roof. The open end of the pipe should be at least 6 inches higher than the roof surface.
- 7
  Apply rubber roof sealer around the pipe to prevent leaks.

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