Roof Drain Vent Question

[gman]

Was wondering why the drain roof vents on our homes are so short and have a cap on them.

All the stick built homes i see have no caps and are at least two times longer than my home.

Can we remove the cap to help keep the vent from being covered up or blocked by winter snow and ice storms.

[Greg]

I suspect they are short due to height restrictions when delivering the home (traffic lights, wires etc). I see no reason why you couldn't add some to give the stacks more height after the home is set up. Greg

[gman]

Thanks for the reply Greg.

The reason this has come up is because we just had a winter storm with a lot of sleet in the mix. It was deep enough that it covered my vents and blocked air flow of sewer gas until enough warm air from the home melted the ice around the vent pipe so it could flow again.

Would it hurt to just to remove the cap so the snow has nothing to build up on and the vent would always be open.

[Greg]

Will it hurt?? I really can't say, but I can say mine blew off about 10 years ago and I have not noticed any problems. Greg

[JD]

Caps are usually not used on comp shingle roofs. The shingles and mastic will seal up the hole the pipe will come through. Hopefully, it was installed with a jack, though I have seen many where it was just a pipe coming out the roof.

On a factory rolled galvanized metal roof, the caps are necessary to seal the hole cut into the metal roof for the pipe. This hole could also be sealed with a plumbing vent jack, which would allow you to extend the vent pipe (usually 1 1/2" abs) up higher. The problem comes when trying to fit a plumbing vent jack from Lowe's or Home Depot, etc. to your roof. These are usually made for a 4/12 pitch. If you have a low pitched roof, you may need to go to a roofing supplier to get the right jack. In my area, I have an HVAC metal company make them for me. That way I can get just what I need.

JD