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TOPIC: Installation Process

pipeless vents

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How would a guy go about properly venting an attic vent that doesn't have a pipe? Also I don't have access to the part of the attic where the hole is located. Thanks, Joe
Joe Busch

5/25/2010
Venting the attic or running up a plumbing vent? Eric Novotny
Eric Novotny
An informed customer is the Best Customer!

5/26/2010
just venting the attic
Guest User

6/2/2010
If you are just venting the attic, what pipe are you referring to? Where is the make up air coming from for the attic? Eric Novotny
Eric Novotny
An informed customer is the Best Customer!

6/2/2010
Look up Air Admittance Valves (AAVs). These allow air into the drain without letting anything out, and can be used in attics and even under sinks (such as for kitchen islands). The big box stores sell them, and I'm sure plumbing suppliers have a wider variety. Plumbing vents serve two purposes. With no vent, water going down the drain would siphon the water out of the trap, eliminating the seal and allowing sewer gases in. For this purpose, air must be allowed in. The AAV serves this purpose. The other purpose is to relieve pressure coming in from the sewer line. With no relief, the pressure would push water out of the traps (at least one of them), again destroying the water seal. For this reason, codes require at least one true outside vent. I'm in the middle of having metal roofing installed. Yeah! We are eliminating all the holes for plumbing vents by using AAVs for all but one, and venting the other one through a gable. (You would have to check local codes for size requirements of the "true" vent and exactly when gable venting is allowed.) Edward
Edward Reid

7/16/2010