main drain vent

[tom41]

is it ok to run the main drain vent through a gable sidewall instead of through the roof? it has been terminated in the attic. I hate to cut through the metal roof. the man that installed it said it would be ok but I think it needs venting outside and could be a problem with moisture on the metal. If I have to go through the metal roof, what would be the best way to install it without worry from leaking? thanks

[glenn kangiser]

If if is a septic vent it has to go outside and above the roof as it will bring sewer gas into the inside and cause health problems or at the worst, death.

http://www.meridianeng.com/sewergas.html

If going through the roof, put it in an area where water will not be blocked by the roof jack.  Usually in the flat between two ribs, or centered on a rib with water allowed to pass on both sides.  You will have to work out sealing for the rib by filling and sealing it or flattening it in the area of the jack, or there are rubber or possibly other  jacks made for the purpose.

I don't think there is a problem with a sidewall exit with proper fittings.  Keep snow in consideration so it does not get ripped off if that is an issue.

[MountainDon]

http://pipe-boots.com/
    uses a dead soft metal collar that is formed to the roof ribs, siliconed and screwed down.  Good for chimneys too

[cmsilvay]

I did not want to cut in my roof so I ran mine out the joists in the loft through the soffit and it has been this way for 3 years and have not issue

[Don_P]

If there is soffit venting don't run any vents or fan exhausts in the area of that roof intake. When repairing that later there will be a streak of mold or rot up the roof bays over that moisture source.