Freezing Vent Pipes on Roof

My husband and I live in Iowa where our winter weather has turned extremely cold (currently 7 degrees). Our home has two 3" vent pipes and one 2" vent pipe on the roof coming from our bathrooms/kitchen. Over the last week, each of the pipes have frozen over. When this happens, our basement smells of sewer gas. To eliminate this problem, we have had to climb up on the roof and pour hot water down each pipe to unfreeze them. Any ideas on how to eliminate the vent pipes from freezing (aside from not using any hot water)? Any suggestions will be greatly appreciated. Thanks.

floerchinger said:

Over the last week, each of the pipes have frozen over.

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Frozen over... I assume because of snow? I don't know if this is legal or to code, but you could dry fit 2 street ells to the top of the vents, that should keep the snow out.

Rancher

Thanks for your response. However, they freezing is not due to snow, just frigid temperatures. The steam rising up out of the pipes freezes when it reaches the roof line and causes the pipes to freeze over.

Heat tape down the vents?

Rancher

It's not snow, it's steam coming up the vents, condensing and freezing.

Next summer change all the vents so that 4" pipe comes through the roof.

Don't take long showers.

Wrap a short heat tape around the vent pipes.

Thanks for the advice. I sure hope it works.