How to close up fire place?

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Don.S

Member
Nov 11, 2017
42
Montreal QC
So i put my stove in a few years ago and have been extremely happy with the performance. Now the wife has decided it it time to finish the basement so i guess i have to choice. My question is how do i close up the old fire place and what is the proper way to run my stove pipe into my liner? Right now i just have the stainless snub flush with the cement and i have stuck the stove pipe into it. 20201205_105528.jpg
 
A lot going on there... Did you install a liner or is it exhausting through the old masonry flue tiles? Refer to local building code and stove manual for clearances to combustibles. You are going to need access later on so an insulated door / removable panel is what I'd be building.
 
Stainless liner. what will i need access for later? When i clean the chimney i sweep from the top down and then remove the stove pipe and suck out the t with a shop vac.
 
Stainless liner. what will i need access for later? When i clean the chimney i sweep from the top down and then remove the stove pipe and suck out the t with a shop vac.
Liners, especially flex, have a finite service life. The last thing you want would be to brick/tile that over then need to tear it all back out just to replace a pipe.
 
Liners, especially flex, have a finite service life. The last thing you want would be to brick/tile that over then need to tear it all back out just to replace a pipe.
It would just be a total rip out with a new t-snout (they come in 2 pieces) not really a game changer so to speak and if the op is comfortable with having to take the black pipe out to suck up the junk with an ash vac then so be it, its done like that all the time.
As far as closing up the space, I'd just continue with the concrete block to make it flush with the existing, then put up a scratch coat and do what ever decorative thing you want to do with non combustible materials.
Oh and remove the fiberglass insulation from around your crock area, replace with mineral wool or just seal it with high temp mortar.
 
Ideally there would be a tee at the wall thimble with an extension on the bottom that is capped to act as a cleanout. In this case, access below would be required.

Otherwise, I'd be inclined to make something removable by framing the opening with metal studs or at least angle iron around the perimeter and then covering with cement board that could be tiled to make it look like an intentional hearth back. If the draft is good and strong the stove might work ok by moving it closer to the wall and going straight up for a few feet and then 90º to a short horizontal into the thimble.
 
I will be breaking out the rest of the stone hearth that is in front of the fire place and then i would like to insulate everything. Can i use metal studs and mineral wool to insulate all the chimney area? If i make a metal block off plate for the flue can i put that in then fill the fireplace with mineral wool? I am not too worried about been able to get back in but i will take the advice of people who know better then i and make it accessible.
What should i be doing where the pipe passes through the wall? Right now it is just a hole i broke in the block. Do i break it bigger and put a insulated thimble or do i cement around it and do something else?