# Insulate around brick fireplace - behind drywall



## Nealtw (Jun 22, 2017)

Do the holes for speakers give you access into the cavity?


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## mrdoyam (Oct 16, 2019)

Nealtw said:


> Do the holes for speakers give you access into the cavity?


Thanks for the reply. They do not, there is a stud right at the edge of the drywall. Where the speakers are going is a separate wall cavity. 

Also, I'll note, I've removed the electrical outlet at the top. It will go below the header.


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## Nealtw (Jun 22, 2017)

mrdoyam said:


> Thanks for the reply. They do not, there is a stud right at the edge of the drywall. Where the speakers are going is a separate wall cavity.
> 
> Also, I'll note, I've removed the electrical outlet at the top. It will go below the header.


Is there a box built around the outside of the FP and what kind of siding is on that?


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## mrdoyam (Oct 16, 2019)

Nealtw said:


> Is there a box built around the outside of the FP and what kind of siding is on that?


I took some more pictures for you. The house is brick. The sheathing and house wrap stops at the framing. There is the standard air gap between the housewrap and brick that you cant see well. I tried to show all of it in these pictures. I'm worried if I spray foam it or something, if water gets back there, it will sit...


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## mrdoyam (Oct 16, 2019)

Here is a marked up view. Maybe this will help.


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## Nealtw (Jun 22, 2017)

mrdoyam said:


> Here is a marked up view. Maybe this will help.


I really think you should build a wall with all or part steel studs in front of that so you can insulate


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## mrdoyam (Oct 16, 2019)

Nealtw said:


> I really think you should build a wall with all or part steel studs in front of that so you can insulate


I like the idea but there isnt enough depth. The brick is about the depth of the framing. Drywall on top of it is all that will fit...


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## Nealtw (Jun 22, 2017)

mrdoyam said:


> I like the idea but there isnt enough depth. The brick is about the depth of the framing. Drywall on top of it is all that will fit...


 frame it out to match that brick and drywall or cement board right over the brick. Protect the edge of the board with metal bead.


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## mrdoyam (Oct 16, 2019)

Nealtw said:


> mrdoyam said:
> 
> 
> > I like the idea but there isnt enough depth. The brick is about the depth of the framing. Drywall on top of it is all that will fit...
> ...


Thanks for the suggestion. I didn't think of cement board. I did consider the moisture resistant drywall in case any moisture gets back there. It is exposed to the air gap right now which can be moist air due to porous brick. Curious what I gain by framing it out. I really could only frame the few inches. I attached another picture. Maybe it helps show the depths better


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## Nealtw (Jun 22, 2017)

mrdoyam said:


> Thanks for the suggestion. I didn't think of cement board. I did consider the moisture resistant drywall in case any moisture gets back there. It is exposed to the air gap right now which can be moist air due to porous brick. Curious what I gain by framing it out. I really could only frame the few inches. I attached another picture. Maybe it helps show the depths better


 Well you should be planning on be comfortable that you have no leaks, you might look at sealing the outside of the brick. moisture getting in the cavity should minimal I think. And the side do have vapour permeable house wrap. 

I am not sure how close to the fire box you can use wood so I think i would just opt for steel and they do make a 2 1/2" if you don't have 3 1/2" or 3 1/4 and you could fill the space there with a mortar to get a good seal around the fire place.


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## mrdoyam (Oct 16, 2019)

Ok, here is my thought. No vapor barrier or any house wrap. Using moisture resistant drywall and cement board. Also ROCKWOOL COMFORTBATT R-15 Stone Wool Batt Insulation with Sound Barrier - Non-combustible, fire-resistant up to 2150 F. Thoughts?


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## Nealtw (Jun 22, 2017)

mrdoyam said:


> Ok, here is my thought. No vapor barrier or any house wrap. Using moisture resistant drywall and cement board. Also ROCKWOOL COMFORTBATT R-15 Stone Wool Batt Insulation with Sound Barrier - Non-combustible, fire-resistant up to 2150 F. Thoughts?


That should work I don't think the back for green drywall is special, I would just use regular.


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