I HAVE A RANCH HOME IN NORTHERN MICHIGAN BUILT IN 1996. ONCE OR SO PER YEAR MY 3″ PLUMBING VENTS FROST UP AND SEWER GAS CAN BE SMELLED IN THE HOUSE. THE TWO VENT PIPES ARE ON THE EAST SIDE OF A 6/12 PITCHED ROOF AND ARE 36″ ABOVE ROOF . CURRENT SNOW DEPTH IS 24″. THIS HAS BEEN A PROBLEM 8 TIME IN THE LAST 6 YEARS, ALWAYS WHEN BLIZZARD CONDTIONS LAST FOR A DAY OR MORE. THE 3″ VENTS ARE COUPLED TO 2″ PVC PIPE 18″ THE ROOF DECK. ANY IDEAS HOW TO FIX THIS IN THE SPRING WOULD BE A GOD SENT. I HAVE TRIED TO GET THE PLUMBER AND INSPECTOR TO GIVE ME SOME IDEAS WITH NO HELP.
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How about taking 10" diameter piece of pvc centering the 3" pipe and fill the gap with foam in a can to insulate it. Then going in side and insulate the pipe in the attic with the foam they use on cold water pipes to keep them from sweating. I think you can get that in large size also.
upc tells us that the vent pipe can be 6" min 12" max i've run across same problem and solved it by following code
I NEED TO UNDERSTAND 6" ABOVE ROOF DECK AND NO MORE THAN 12" IS THE CODE. I HAVE AT LEAST 18 TO 20" OF SNOW ON ROOF AT PRESENT.
i would say come spring measure from the roof deck and if you think vent is to small in diamiter you can always increase diamiter in attic if need and extend it out roof.
looks like my best option so far. thanks
DRW; I had a similar problem. Found out I had about 7-8 ft. of horizontal run in the attic. It did not have enough pitch and was holding water. The water was condensing in the cold stack that was above the roof. Only happened in real cold . I fixed it this summer and so far I have not had a problem. See if any of your vent pipes have standing water. Hope it helps.
thanks for your help. my problem is frost above the roof line between snow level and top of vent stack. to correct i have to re-open the vent with a screw driver, it's not frozen solid like ice cubes. i have checked for proper pitch on the horizonal run before.
I had to use a 6' piece of 1/2" conduit to free mine. Somewhere you are getting excess moisture.
Increase size/diameter.
Snow above the vent should have much effect: when the snow piles over it, the warm moist aiur rising in the vent will melt the snow directlt above and the snow melt will just drain away.
BTW, please turn off the ALL CAPS. It is very hard to read messages in all caps, and using all caps on the internet is generally considered to be a form of shouting. Thus some folks just skip messages in all caps and you limit the number opf responses you're likelt to get.
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"I may have said the same thing before... But my explanation, I am sure, will always be different." Oscar Wilde
Edited 1/31/2003 7:13:58 AM ET by Bob Walker