Wood insert clearances to combustibles

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mtrainier

New Member
Dec 15, 2021
1
PNW
I'm new to the forums and have been searching for wood insert clearance information.

I'm looking at getting a wood insert for my existing fireplace -- specifically looking at the Hearthstone GMi70.

I have an original open masonry fireplace, where the fireplace front brick extends 47" high -- from the floor up where the first piece of horizontal wood (lathe and plaster) shows. From what I can tell, the wall framing starts at this point and is built around/on top of the fireplace brick.

So, after re-tiling the fireplace surround, that wood framing would be set back from the face of the fireplace surround by about 1" (where ceramic tile would comprise the surround facing). In other words, the depth of the tile surface would be 1".

So, my question is whether the clearance specifications for the GMi70 (and wood inserts in general) are intended for only the fireplace surround face (materials protruding out from the fireplace face) or whether it is also cross-section clearance. I.e., whether the wall wood framing interior to the wall (starting 47" above the fireplace floor) would not comply with the clearance requirements. For context, the GMi70 states it should have 50" of clearance to combustibles from the bottom of the insert (floor) to the first combustible.

Thanks in advance for your help!

fireplace surround (2).jpg


fireplace surround (2).jpg
 
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kennyp2339

Minister of Fire
Feb 16, 2014
6,693
07462
For a full masonry fireplace that uses refractory high temp bricks and is solid with 8" thick total masonry or more the clearance is for materials protruding like a mantle, floor in front of the unit, side walls if the insert isn't flush mounted,
 

EbS-P

Minister of Fire
Jan 19, 2019
3,511
SE North Carolina
So the wood in the picture is what you are concerned about. It clear that the fireplace doesn’t meet code for 2” clearance to combustibles. so I think the question is, even if you install an insulated liner is the current fireplace safe and code compliant for an insert install? I don’t have the answer.

in general adding non combustibles in between insert and combustible does not change the minimum distance to combustibles. The exception is a ventilated heat shield With non combustible stand offs.
 

Ctwoodtick

Minister of Fire
Jun 5, 2015
1,780
Southeast CT
So the wood in the picture is what you are concerned about. It clear that the fireplace doesn’t meet code for 2” clearance to combustibles. so I think the question is, even if you install an insulated liner is the current fireplace safe and code compliant for an insert install? I don’t have the answer.

in general adding non combustibles in between insert and combustible does not change the minimum distance to combustibles. The exception is a ventilated heat shield With non combustible stand offs.
I could be wrong but I believe using an insulated liner allows for the wood to touch the outside of the masonry structure, providing “zero clearance”. This is in general, I believe- I’m not sure if the pics provided by the OP indicate a specific issue or not.