# How to Insulate Around Basement Fireplace



## Windows on Wash (Aug 30, 2011)

Check with the code inspector in the area based on what you are putting in and err on the side of caution. 

Roxul makes a rigid rockwool board that would probably work here. Polyiso does well under roofs and hot areas but it is not rated to be exposed so that is the consideration.


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## NickWa (Nov 17, 2011)

I forgot about roxul board, it isn't vapor barrier though right? Id have to have poly somewhere


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## Windows on Wash (Aug 30, 2011)

Meh. Painted and trimmed out drywall, when sealed, isn't letting a bunch through it.


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## NickWa (Nov 17, 2011)

Windows on Wash said:


> Meh. Painted and trimmed out drywall, when sealed, isn't letting a bunch through it.


I'm thinking I bring the XPS within 6" of the sides and to the top of the heatform on the top. Then I'll bring the Roxul board to the opening of the firebox and seal between the XPS and Roxul board with spray foam.

I will be using steel studs to frame out the opening of the fireplace and I'll fill the cavities with Roxul wool. Then concrete board over the steel studs and drywall over the wood studs. Considering behind the Roxul board is the chimney cavity I wouldn't expect there to be a lot of moisture penetration here anyways. Also, there will be no moisture through the heatform obviously.

Thanks for the reminder about the Roxul board!


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## Windows on Wash (Aug 30, 2011)

No sweat. I also don't think there is going to be much moisture penetration there and especially in that 6" of relief. 

Make sure the box is well sealed to the concrete so there is no air gain around there.


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## NickWa (Nov 17, 2011)

Here is my plan for doing around the fireplace / fireplace insert. I need 6" on the sides and 16" above for combustible clearances. I will do steel studs over Roxul board for the non-combustible part and Roxul batt in the stud cavities. Outside of the non-combustible zone will be normal wood studs over XPS, and fiberglass batt.

X = XPS
R = Roxul Board
Brown = Wood framing
Green = Pressure Treat plate
Blue = Steel stud


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## Windows on Wash (Aug 30, 2011)

I would make the sections directly beneath the fireplace Roxul as well.

Everything else looks solid.


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## NickWa (Nov 17, 2011)

Windows on Wash said:


> I would make the sections directly beneath the fireplace Roxul as well.
> 
> Everything else looks solid.


Fair enough, I will have plenty of board leftover from a bag still anyways.

Thanks for keeping up!


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## Windows on Wash (Aug 30, 2011)

Yeppers.

Great progress by the way.


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