Insulating around wall thimble

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cham1733

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Jun 25, 2014
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Thank goodness for this forum. You guys have helped me quite a few times already. When the hole was cut for our wall thimble they ended up taking some extra out around the thimble (not purposely) and now I can feel a draft coming through. What would be the best thing to put there to insulate? I have attached a few pictures below to demonstrate what I mean. If you look around the all thimble there is an open space that I would like to close up. I am guessing that reluar insulation would be fine but I also found a 1” ceramic fiber insulation blanket on Amazon I was thinking would work but I was hoping for some opinions. Also can I caulk or put anything around the pipe going on the inside on the house where it goes through the thimble to seal that off. If you look at the bottom picture you can see a space between the pipe and the thimble where it doesn't fit tight.
Insulating around wall thimble Insulating around wall thimble
 
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What brand thimble did they use to go through the wall? What is on the outside wall where this pipe comes out?
 
It is a Selkirk.The pipe goes through the wall to an elbow and then up. There is a piece of insulation on the inside of thimble on top of the encassment the pipe goes through.
 
Can you post a picture of the outdoor side? Something doesn't look right with this install. If you could pull the trim ring on the inside and show what is behind it that would also be helpful. My concern here is lack of proper clearances going through a wall. Insulation is not enough. This is a Selkirk Supervent wall pass-through diagram. Note the 3" protrusion of the class A pipe into the room.

Insulating around wall thimble
 
I am not home right now but I can later if it would help. I can try to describe it. The regular insulation you see on the pictures stops at the outside of the thimble. In the inside there is the pipe, then around that is the thimble, then open space, and then our blockwall. Our double wall pipe runs through the thimble and to the outside 4 inches or so and then connects with the elbow so we are 6in away from the siding. On the inside the double wall pipe runs into the house ~20in then connects to our elbow and stove pipe. So we would have basically 20in of double wall chimney pipe running into the room. Running the pipe through the thimble and having the 2 or 3 inches around the thimble of airspace was enough according to the Dura Tech instructions, unless I misunderstood them. I think I might of answered your question. If not let me know and I can take some pictures tonight.
 
DuraTech is not Selkirk, it is DuraVent pipe. I need to see more from back further. It is impossible to figure scale in the picture so one can't see what pipe is being used or where it transitions to regular connector. Normally the class A chimney pipe only comes 3-6" into the room. Also, there is no such thing as an exterior 90deg. elbow. for chimney pipe, only a tee connection with a cleanout can make a 90 deg turn outdoors.

My concern here is that interior connector pipe was used instead of chimney pipe. If so, this is a dangerous installation. But I will wait until later to see the outdoor and indoor details.
 
Sorry for the confusion. Double Wall chimney pipe (Dura tech) was used through the thimble (which is a Selkirk) and connects on the outside to our tee connector with cleanout. The Dura Tech chimney pipe runs about 20in in the inside of our house to the connector which connects the chimney pipe to our black stove pipe elbow and then pipe. It sticks out so far into the room because a 3ft section of the Dura Tech (chimney pipe) was run through the wall thimble. Is there an issue having the Dura Tech come so far into the room? Sorry I am terrible at trying to explain this. I will take pictures later tonight. Thanks for the help.
 
No problem, that sounds safer. I was confused by the use of combined brands, but what you say makes sense now. 20" of class A pipe into the room is kind of ugly. Normally an 18" length for this setup would be sufficient and more trim looking.

Did you silicone caulk or stuff any insulation between the pipe and the thimble on the exterior side? The thimble itself is can be sealed with JUSI/SUSI insulation.

Insulating around wall thimble
 
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No problem, that sounds safer. I was confused by the use of combined brands, but what you say makes sense now. 20" of class A pipe into the room is kind of ugly. Normally an 18" length for this setup would be sufficient and more trim looking.

Did you silicone caulk or stuff any insulation between the pipe and the thimble on the exterior side?

Ya, it is not very appealing. But then again neither is that whole room (future project).The thimble has a piece of insulation that went around the ring on the inside of the house and then a piece that went around the inner metal part that the chimney pipe went through. I attached a picture below . That was part of of original question was if I can caulk around the pipe. I am assuming I can by your question. In that case I will be caulking the outside when I get back home today. Any idea of what I can do for the inside around the thimble wall where they cut the board back too far? Would my best bet just be to caulk there as well?

Insulating around wall thimble
 
Should be ok to caulk around the trim ring inside. Some lacquer thinner may remove the ink marks below the pipe. Be careful not to get any on the trim ring as it may also remove the paint.
 
Should be ok to caulk around the trim ring inside. Some lacquer thinner may remove the ink marks below the pipe. Be careful not to get any on the trim ring as it may also remove the paint.

Ok. Thanks for all your help. It's definately appreciated.
 
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