insulation behind the fireplace facing?

[RickF]

Hello,

My question is what kind of insulation should/should not be behind the framing for the fireplace facing, i.e., above the fireplace and near/around the large ducts in the chimney (there are liners also inside the large ducts).

In a remodel of my house, I am refacing the fireplace, which gave me the chance to see behind the framing that holds of the facing.

I never knew what a fireplace looked like inside, but as my contractor finished some framing and wiring before the refacing, I noticed he was replacing insulation.

My concern is that some of the insulation is the kind that has paper facing on one side. Sounds like a bad idea to me to have near a fireplace. Any guidelines for whether/what kind/how much insulation to have in this cavity behind the fireplace facing and around the large ducts?

Rick

 

[webby3650]

Typically you would use unfaced insulation inside the fireplace chase. Make sure there is also a draftstop installed at the ceiling height. Otherwise cold air will pour out around the fireplace! Got any pictures of it?

 

[RickF]

Typically you would use unfaced insulation inside the fireplace chase. Make sure there is also a draftstop installed at the ceiling height. Otherwise cold air will pour out around the fireplace! Got any pictures of it?

I do have photos - haven't gotten this system to work yet. Look like it works when I attach to a reply. I suspect I should remove the insulation with the backing on it. As you view the chase here, what should be insulated? What is a draftstop?

 

[begreen]

The insulation bats should be supported so that they can't all out. Criss-crossing with string is one method. Covering with sheetrock is often suggested. There should be a firestop, (draft stop) at the ceiling level.

 

[RickF]

The insulation bats should be supported so that they can't all out. Criss-crossing with string is one method. Covering with sheetrock is often suggested. There should be a firestop, (draft stop) at the ceiling level.
View attachment 186224

What is a draftstop? How do I implement it?

 

[begreen]

It's a sheet metal plate that surrounds the chimney and goes to the chase walls to create a block. Remember to maintain the 2 in. clearance to combustibles all the way up.

 

[webby3650]

The entire fireplace chase needs a ceiling in it. It needs to be 3/4" plywood minimum, then the chimney will pass through a metal fire stop that will maintain 2" clearance.