Pesky pesky Selkirk chimney leaks

Started by Ernest T. Bass, November 11, 2020, 10:35:46 AM

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Ernest T. Bass

Hey guys! Been a while.. finishing up a kitchen addition on our cobwood home (probably deserves its own thread), but for now, chimney leaks!

It's a Selkirk system, cathedral ceiling with a metal roof. I have 6'' of Polyiso insulation. I was getting intermittent leaks during rainstorms that I couldn't pin down. I read that these Selkirk pipes can wick water into their vertical seams and bring rain down past the boot. I caulked all the seams, and I'm still getting drips.

Problem is, now that it's cold I can't tell how much of it is rain and how much is condensation! After pulling off the trim plates and keeping an eye on it for a few days, I can see the inside of the rubber boot is covered in condensation. My question is, how is this not a design flaw? You're required to cut back all insulation/vapor barrier at least 2'' from the pipe. That just allows warm, moist ceiling air to shoot right up under the cold roof. Anyone else have this problem?

https://drive.google.com/file/d/1WBjEplLSXPO78OjVF4bppm5_OtSAUGzG/view

https://drive.google.com/file/d/1a0dduDWoI9fFO9tdD3HKQtNjdI-YTD24/view

https://drive.google.com/file/d/19JR5IvzBYlQj0OMYf-JDmYwPXAeeG4_m/view

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JRR

Do you have another heat source?  If so, you could stuff this area with cloth and check periodically to see if condensation is stopped, or rain drops come through.

If the problem proves to be condensation, you might consider stuffing the space with stainless steel wool.  A sizable roll can be had for under $100.

... this from a guy who has absolutely no experience with a problem such as you are having.   Good luck!


akwoodchuck

The design flaw is not in the chimney, but in your house. In modern cold climate construction, warm, humid interior air should never have a direct pathway to a cold surface, or condensation will occur. That's why air sealing, handling, and exchanging take up, pardon the pun, so much oxygen in the building design process....
"The lyf so short, the craft so long to lerne."

MountainDon

Years ago, right after installing the chimney,  we had a leak that allowed small amounts of water to drip down onto the stove top when it rained. It was also a Selkirk brand chimney. It took forever but I finally stopped the leak when I silicone caulked one of the joints where two sections of insulated pipe coupled together. It was in desperation that I removed the S/S clamp band, applied silicone and wiped it into the joint, then replaced the clamp band.
Just because something has been done and has not failed, doesn't mean it is good design.

Ernest T. Bass

Quote from: akwoodchuck on November 11, 2020, 12:05:32 PM
The design flaw is not in the chimney, but in your house. In modern cold climate construction, warm, humid interior air should never have a direct pathway to a cold surface, or condensation will occur. That's why air sealing, handling, and exchanging take up, pardon the pun, so much oxygen in the building design process....

Understood, but I am unable to run insulation or a vapor barrier right up to the pipe as per the manufacture's instructions.

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Ernest T. Bass

Quote from: MountainDon on November 11, 2020, 02:12:28 PM
Years ago, right after installing the chimney,  we had a leak that allowed small amounts of water to drip down onto the stove top when it rained. It was also a Selkirk brand chimney. It took forever but I finally stopped the leak when I silicone caulked one of the joints where two sections of insulated pipe coupled together. It was in desperation that I removed the S/S clamp band, applied silicone and wiped it into the joint, then replaced the clamp band.

I do think I was getting a similar type of leak as well. I hope that caulking the vertical seams fixed it... I took the bands off and thought about caulking in there, but I'd rather not glue the pipe sections together. You've never had condensation? We do have a particularly humid home.. Perhaps someone with low humidity who is always using the stove in cool weather would not have a problem. I think when the stove is in use, that gap is warm enough to prevent condensation. Also, the metal trim plate underneath could be a vapor barrier if it was caulked I suppose. My wood ceiling has small gaps between the boards, however, which would still let moisture behind the metal plate.

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MountainDon

I wasn't keen on caulking the joint either, but by that time I had exhausted every other possible entry point. 

No, we've never seen any condensation anywhere around the chimney. We used one of those silicone rubber boots on a metal roof. My first thoughts were that I had messed up sealing it. but no it was, and still is, good. The climate is on the dry side but even with a pot of water evaporating on the stove during the winter the only condensation anywhere inside has been on window glass on occasion and mostly in the shower room.

Do you have snow on the ground? We have a little but it melts a little every day.
Just because something has been done and has not failed, doesn't mean it is good design.

Ernest T. Bass

Quote from: MountainDon on November 11, 2020, 03:01:58 PM
Do you have snow on the ground? We have a little but it melts a little every day.

Just got an inch last night! Also melting.. coming off a crazy warm week. We hit 83 degrees a few days ago! Go back even further, and October had blizzards and we hit 15 degrees one night. Nuts!

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