Stove Installation Against Cultured Stone?

[Jeff Childers]

I am designing my house and I want to install a VC Defiant stove in a nook that will be covered with cultured stone. I know this stuff won't burn, but it is just glued to a sheetrock wall and that makes me wonder if I have to worry about clearances. Any suggestions?

I could install some other backer board on the studs for the cultured stone to adhere to if necessary.

I need advice.

Thanks
Jeff

 

[begreen]

You need to use the maximum clearances recommended for the stove in this configuration. That would be 24" on the sides and 33" to the rear for the Defiant Cat 1945 without heat shields. Back clearance can be reduced with the heat shield and doublewall pipe.

Or the clearances can be further reduced if the cultured stone is installed over cement board (durock) that has a 1" air gap behind it. This is not as hard as it sounds. Use double 1/2" durock strips on each wall stud as "firring strips" to create the air gap. Leave it open about an inch at the bottom and top to aid airflow behind the wall.

 

[Corie]

Good advice BG!


The only thing I would add is that when cutting the strips of durock to use as "firring", be certain not to try and make them too narrow. The durock will be very crumbly and difficult to cut and break off if you're trying to make 1 inch wide strips and then trying to send a screw through them.

 

[webbie]

It should be mentioned that the clearances usually apply to the combustible wall - so if the stone and the cement board (with no space) take up 2", then you can save a total of 4" off the width (no air space)....

Although in theory it would be possible to protect walls with no air space (like hearths), in practice this is not usually done. NFPA does have specs using a real brick against a combustible wall for a 33% reduction (to original combustible wall, once again).

 

[begreen]

Good point Corie. The furring strips should be about 3-4" wide. There is info on how to do this on Durock's website.

 

[Highbeam]

I cut a bunch of 3-5/8" strips of 1/2" durock using an abrasive blade in my circular saw. It was very easy, just like cutting plywood only dustier. The strips were quite stable and I even did a destructive test of scraps of the strip. The mesh provides great strength even after the concrete cracks.

To create the 1" offset any noncombustible can be used such as steel square tube or the top hat style sheet metal spacers.

If just gluing the veneer to the sheetrock, the advice on this site has been that the combustible surface is the stove side face of the noncombustible veneer. In effect, the stone has to fall outside of the required clearances.

 

[jqgs214]

Cut mine with a sheetrock knife, scored it enough to get through one side mesh and just snapped it, works like a charm.

 

[Jeff Childers]

Thanks to all of you for your idea. But I have one more question.

If I use metal studs around this cove, attach the concrete board to that and then attach the cultured stone (made of concrete) to that, I'll have nothing combustable on this side of the wall. Even if I have sheetrock in the room on the other side of the cove wall, surely there won't be enough heat penetrating the wall to cause concern in the room behind the cove. It seems to me that I can place the stove fairly close to the stone wall of the cove. I mean like 6" to 10" between the stove and the stone wall.

Would the use of metal studs allow me to do this?

Thanks,
Jeff

 

[begreen]

You can not reduce clearances for this situation below the manufacturer's stated minimum clearances without violation. Metal studs would be overkill for air space and would not change the spec. Use the durock shims, it's cheaper and easier. You'll need to work with the stove's clearances or perhaps look at another top loader, like the Quadrafire Isle Royale for reducing clearances? What are the dimensions of the alcove?