"B" Gas Vent question...

[Paul Geer]

I have a gas-fired unit heater in my garage 30K Btu with a 3" B-vent or double walled stack through the roof. There is water coming in looks like around the outside of the vent pipe when we get a heavy blowing rain. It amounts to a few drops on the floor enough to just cover the bottom of a five gal. Bucket.

On the roof, the vent pipe is not sealed to the roof flashing but the storm ring is sealed with what looks like gutter sealant. Should the vent pipe sealed to the roof flash as well? I've received two options on this from two different contractors, one says yes it should and the other said no, "there should be movement because of the roof".

Any ideas?

[Lee Schierer]

As I recall, the double walled pipe on the stove my Dad put in his work shop had a sloped collar that went just above the roof cap that shed the rain outside the inner dimension of the roof cap. This ring acted as an umbrella for the roof cap. There was no sealant.

[Bruce Page]

Paul, my vent pipe is sealed to the flashing. It hasn’t leaked yet.

[Paul Geer]

Thanks Lee and Bruce for the replies, I was just up on the roof today here at work (the woodshop) and we have three B-vent stacks and all three are sealed to the flashing or roof jack. I'm going to hold off sealing the stack to roof jack at the home woodshop untill I find a wider storm collar and give that a try. The one that's on there now is 1" wide. Wish me luck!

Thanks guys,

Paul