How to Add a Plumbing Vent
Plumbing vents allow gasses to exit the waste water pipes of the home sewer system. Waste water flows on the downward slope of the pipes while the gasses flow up through the vent exiting through the roof. Adding plumbing fixtures may require the addition of plumbing vents, although additional vents can also address problems such as gurgling or slow drains. Does this Spark an idea?
Instructions
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1
Cut through a segment of the horizontal waste water pipe. Use a hacksaw to cut through the PVC pipe. Remove a segment of the pipe large enough to accommodate a T-fitting.
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2
Place the T-fitting between the two segments of the pipe. Dry fit the fitting in place to make sure it fits properly. Remove and coat the interior of the fitting with PVC glue and replace.
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3
Connect a vertical piece of PVC pipe to the fitting. The vertical portion of PVC pipe will ultimately extend up through the ceiling and roof of the home. The pipe commonly fits within the cavity of the stud wall to extend through the main floor of the home to the attic.
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4
Drill a hole to accommodate the size of the pipe through the bottom plate between the studs of the wall. Drill a second hole through the top plate directly above the first hole. This creates an opening from the basement level through the wall cavity into the attic. This work is done before drywall is applied to the stud wall.
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Locate the position on the underside of the roof directly above the position where the PVC vent pipe extends into the attic. Move a string tied to a weight around the underside of the roof until the weight is directly above the pipe. Drive a nail up through the roof surface to mark the position.
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Cut through the shingles of the roof to create an opening the same size as the diameter of the PVC vent pipe. Drill a hole through the roof deck to accommodate the pipe.
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Extend the PVC pipe through the hole. Use straight fittings to connect pieces of pipe together to fit through the roof. Seal the area around the vent pipe above the roof with roofing tar.
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Tips & Warnings
Use the same size PVC pipe for the entire vent pipe. The size of the vent pipe depends on the number of plumbing fixtures near the vent. The vent pipe should extend at least 6 inches, but no more than 12 inches, above the roof. Check local building codes for particular specifications.
