Summer Chimney Cap

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Woodcutter Tom

Feeling the Heat
Apr 28, 2019
334
Northern Illinois
I had earlier posted a Summer Shutdown Process thread where I mentioned I wanted to cap the top of my chimney during the summer. I wanted to prevent birds, critters, rain, and hot humid air from entering my chimney.

This is what I found and it works perfect.


I have 6" Selkirk double wall class A insulated chimney sections. This cap has a inside ID of 8 1/4". It fits perfect over the chimney pipe. The hose clamp snugs up the cap right under a ridge on the chimney pipe. It won't blow off.

Yesterday I had a bird in my stove. I was able to get it out by covering it with a towel. The bird did not struggle too much. I let it go unharmed outside.

By chance the Fernco cap arrived yesterday, so I installed it. It is just what I wanted for my needs. Perhaps this will help someone else.
 

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I had earlier posted a Summer Shutdown Process thread where I mentioned I wanted to cap the top of my chimney during the summer. I wanted to prevent birds, critters, rain, and hot humid air from entering my chimney.

This is what I found and it works perfect.


I have 6" Selkirk double wall class A insulated chimney sections. This cap has a inside ID of 8 1/4". It fits perfect over the chimney pipe. The hose clamp snugs up the cap right under a ridge on the chimney pipe. It won't blow off.

Yesterday I had a bird in my stove. I was able to get it out by covering it with a towel. The bird did not struggle too much. I let it go unharmed outside.

By chance the Fernco cap arrived yesterday, so I installed it. It is just what I wanted for my needs. Perhaps this will help someone else.
I would much rather let some air move through the chimney
 
I recently switched out my stove pipe cape to this:


Not at that price though! I love the large openings, I'm hoping that they don't clog up. I think it would get old really fast having to go up on the roof more times then needed just to switch out caps. I'm going to try it out this burn season, and I have the old cap of course which is still in itself pretty new just in case this one doesn't perform as well as my original cap. The only reason I changed mine out was like you, I woke up one morning to a bird in my firebox. Didn't care to deal with this issue all summer so wanted something to keep the critters out!

This is basically what my original cap looks like:


Great for wood stoves but no way of keeping animals out of your pipe.
 
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I would much rather let some air move through the chimney
Thanks for the link. I ordered a6” one for each flue.

As for air flow. I want to keep it out planning on a blower door test this summer
 
Thanks for the link. I ordered a6” one for each flue.

As for air flow. I want to keep it out planning on a blower door test this summer
That means you will have condensation in the chimney unless you completely seal top and bottom. An add quite a bit of dessicant.
 
That means you will have condensation in the chimney unless you completely seal top and bottom. An add quite a bit of dessicant.
Where you likely see the most condensation? At the top??
 
Im going to put small hole wire on it and use hose clamps. It will keep out the bigger animals.
 
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Down here multiple days a year there is condensation on the outside of my windows. Read that as the dew point goes above 80 regularly. I do see how house air being drawn up keeps the flue dry.

I stuck my temp/humidity logger in my stove. I’ll report back what it reads In its own thread. Probably will put it 4 feet down from the top then cap it and collect some data too.