Blocking off the chimney from the fireplace

[joann5]

Anyway, I am wondering what is to be done about blocking off the chimney flues from the fireplaces. There are no dampers. What is normally done re: materials and such? How is it done and who does it? A mason? A chimney sweep? A gas installer? Can it be a DIY job for a handy person?

Thanks.

 

[BrotherBart]

Make a block off plate but don't cut the hole for a liner in the middle of it.

https://www.hearth.com/econtent/index.php/articles/making_a_block_off_plate/

 

[joann5]

Make a block off plate but don't cut the hole for a liner in the middle of it.

https://www.hearth.com/econtent/index.php/articles/making_a_block_off_plate/

Awesome! And I have enough basic skills to do it myself.


One question: Will any silicone sealant stand up to the heat or does it have to be a special kind?


Thanks!!

 

[BrotherBart]

My stove gets a hell of a lot hotter than any ventless gas unit will and the ACE Hardware silicone around the edges of the block off plate looks brand new after three years. Those bricks on the side of the chimney are a heat sink. That stuff doesn't get very hot. The hottest my infrared thermo had ever read on the fireplace firebrick was 238 degrees. Plain old silicone caulk is good to 450 degrees.

Of course I have to also say I wouldn't have a vent free gas appliance in this house if you held a gun to my head.

 

[joann5]

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[North of 60]

The colder weather is when you are going to use it and thats when your going to get the most condensation. It will pool up there if you put holes in it. The products of combustion are very acidic. With that moisture collecting there it will even be worse. Stop convincing yourself that it will be OK. The school of hard knocks is already tough as it is.
N of 60