Retrofit blockoff plate?

[Ctwoodtick]

So I have an insert with ss insulated liner going all the way to top of chimney. Installer had room to put liner through old damper so did not have to remove. He shoved roxul in the damper area to cut down on heat loss from insert. At this point I do not want to remove old damper with insert installed. Also don’t want to remove insert to have damper removed. Is there any way to put in a block off plate at this point that connects to old damper? Not so much thinking about heat loss but end up getting some small amounts of roxul dust that I think falls and gets picked up by the blower. I imagine a blockoff plate or something like that would correct that. More heat always welcome too of course.

 

[KennyK]

I’m not sure how you can accsss the area where you need to get to for the block off plate without move the insert, but perhaps when you remove the insert surround you have some access. I’d recommend making a two piece block off plate, which might be your only option and should work great. I’m attaching pics of the one I made to give you an idea. You can seal the two pieces with high temp silicone.

Here’s a link to the wiki on how to make a block off plate: https://www.hearth.com/talk/threads...ock-off-plate-for-a-masonry-fireplace.147679/

Here’s a post I put up last spring with some questions about my block off plate, which you may find helpful:
https://www.hearth.com/talk/threads/sealing-block-off-plate-question.168661/#post-2264457

Good luck!