Advice on Building Floor / Wall Pad

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zenner

New Member
Feb 29, 2008
3
NJ Shore Area
We are building a 30 x 15-20' single story L shaped addition that opens to a kitchen (and a staircase running to our 2nd floor)... about 600 sq ft for the room alone, and are thinking of adding a wood stove in a corner of this room. For now we are considering a Jotul F 400 Castine ... it seems about the right size, has low clearance for a corner installation, and the styling is right. But we're not "sold" yet since there are other manufacturers in our area. Anyway...

To get the close clearance (I think 6" according to the manual) you need a protective surface on the walls near the stove. I could easily build this myself if supplied with accurate and safe recommendations / instructions. So I'm looking for a website or link or information regarding how to build these wall protectors (and floor protection as well). I have the basic concept: tile over a noncombustible surface with spacers to allow an air gap between the sheetrock and the protective wall, but I would appreciate specifics. For example, what's a suitable (and inexpensive if possible) substrate (board). Is 1/2" concreteboard suitable and sufficient? And what about spacers? I've read to use ceramic spacers or maybe pieces of the concreteboard ... but what about the actual fasteners (I would think metal screws could possibly transfer heat to the studs behind the sheetrock). And, if anyone has a recommendation or two on what type of tile to use (or if there are some tile materials to avoid). I'm thinking to build this protective wall from near the floor level (understanding that I need to leave a gap for air to circulate behind the wall) up to near the ceiling ... maybe 10 feet. So weight may be an issue. This would provide a dramatic background for the stove (and the pipe). But would the height prevent air circulating behind the wall (don't think so, but still a question)?

So, if anyone has information ... what to do and what to avoid, I would appreciate a reply.

Thanks!
 
Use 3" strips of the durock cement board as the spacers. Don't stress over the screws, just don't place a spacer strip directly behind the hottest part (flue).

Here's a link to instructions for the durock:
http://tinyurl.com/nmmt3
 
Let me be sure I have the dimensions correct. The space will be 30' x 15' with a 20' ceiling? Cathedral ceilings may be visually impressive, but with heating prices only going up, I would design with a lower ceiling and make the upper space storage. If the plan is set in stone then perhaps consider getting a Jotul F500 Oslo and building a larger hearth. The stove will need greater clearances on the left side to accommodate the side door if you choose to use it. And also add a couple ceiling fans to help distribute the heat that will stratify at the peak.
 
Good question! No, the ceiling height is approx 10' average. The room is "L-shaped" and is approx 15' at narrowest and 20' at widest. I expect everything to be well insulated, but there will be French doors and a large bay window (all thermal glass, etc.). We probably will install a couple of ceiling fans to distribute the heat better. Thanks, Hal
 
the 5/8" thick cement board would be well suited to this installation. using the spacers between creates a hat channel for any heat buildup to escape before reaching the gypsum wall. clay or porcelain bodied tile or dimensioned stone, (ie: slate, granite) should be installed with a heat resistant adhesive rated over 400 degrees. the cement board screws are hardened steel and should not be affected by any extremes.


salohcin

stihl 250
jotul oslo
 
Sounds good Hal. The Castine is a nice stove and works well for corner installs.
 
I noticed in the document for the cement board, the pipe to wall clearances are only reduced to 12" minimum. Several of the stoves I have been looking at have this as the minimum already. Is there a way to reduce the minimum clearance even further. It appears some manufactures allow less clearance space for the back of the stove to the wall, with the use of double wall pipe. I reallize this may not be a big deal, but it is the biggest complaint of my wife.

Thanks,

aussieblake
 
Ultimately I think the stove manufacturer's documentation is the final decision. If they haven't tested and published documentation for further reducing clearances, you are on your own to discuss a variance with the inspector based on additional measures like a wall heat shield. This is unfortunate because in some cases you know that adding a wall shield will improve the situation, but you will need to prove it based on NFPA variances.

FWIW, I think the 12" rule for clearances to unshielded combustibles for the Castine is a good one based on our installation. The good news is that in their documentation they do cover the wall shield case and reduce clearances to 6" with a proper wall shield, rear heatshield on stove and double-wall pipe. So with the F400 it is possible to reduce the 12" clearance by half with a bit more prep work.
 
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