Extend fireplace opening?

DC123

New Member
Jan 5, 2017
3
DC
Hello,

We have a fireplace that's 29" wide. I'd like to be able to install a 34" gas insert, however. With the amount that they taper, I think there are several that are 34" wide at the front, but taper back far enough to fit into the 29" firebox opening after 9" or so, if I can widen the outer brick surround (please see pictures).

So the big question is, do you think that the outer brick surround can be cut back a couple inches on either side (and to a depth of 9" - where the outer white brick hits the refractory brick in the picture) without destabilizing anything? It looks to me that there is a lintel, but I'm not sure how far it extends.

Thanks in advance!
 

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bholler

Chimney sweep
Staff member
Jan 14, 2014
21,894
central pa
We have a fireplace that's 29" wide. I'd like to be able to install a 34" gas insert, however. With the amount that they taper, I think there are several that are 34" wide at the front, but taper back far enough to fit into the 29" firebox opening after 9" or so, if I can widen the outer brick surround (please see pictures).

So the big question is, do you think that the outer brick surround can be cut back a couple inches on either side (and to a depth of 9" - where the outer white brick hits the refractory brick in the picture) without destabilizing anything? It looks to me that there is a lintel, but I'm not sure how far it extends.
Well yes it is possible but not practical it would mean cutting in and installing support above the current lintel then removing it and the entire firebox and possibly smoke chamber then reconstructing. You are talking allot of work and money just get an insert that fits
 

DC123

New Member
Jan 5, 2017
3
DC
Huh, ok thanks. So you think it's unlikely that the current lintel extends far enough out to cut even a couple inches away? I'm not sure I understand why the firebox would need to be removed. And wouldn't you want to put support under the current lintel rather than over it? Clearly I don't understand how fireplaces are constructed...I'd been assuming the outer brick surround was decorative rather than structural.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
21,894
central pa
So you think it's unlikely that the current lintel extends far enough out to cut even a couple inches away?
It probably extends as far in as it needs to to support the opening if you take some of that support away who knows what will happen.

I'm not sure I understand why the firebox would need to be removed
Because it needs to be wider to it is flush with the opening so it will not be wide enough and being that they are laid on edge they will be very unstable and will likely collapse once you start messing with them

And wouldn't you want to put support under the current lintel rather than over it?
No because you are going to have to remove that lintel and replace it with a wider one. You need the support above to keep the structure from collapsing when you do that.

Clearly I don't understand how fireplaces are constructed...I'd been assuming the outer brick surround was decorative rather than structural.
It usually is but it still needs to support itself. And your firebox is not wide enough anyway so it needs modified as well
 

DC123

New Member
Jan 5, 2017
3
DC
Got it, thanks for the detailed explanation. Do you think the firebox would actually need to be altered? My thought was that the insert would have narrowed to the width of the 29 inch firebox assuming it was placed flush with the surround.

Do you think a longer lintel could be inserted directly under the current one? That would seem to solve the structural issues.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
21,894
central pa
Do you think a longer lintel could be inserted directly under the current one? That would seem to solve the structural issues.
No probably not unless you stuck it on the face which would then make it visible unless the insert surround would cover it.

Got it, thanks for the detailed explanation. Do you think the firebox would actually need to be altered? My thought was that the insert would have narrowed to the width of the 29 inch firebox assuming it was placed flush with the surround.
I just noticed that your face is 2 brick think in that case it is possible. You would have to get exact measurements of the insert.