Yet another floor/wall protection question...

[mjjochen]

Hi folks, I've been "lurking" here for a while and have picked up quite a few tips that will help me on a coming install of a VC resolute acclaim that I just picked up. Thanks for all the good info!

The stove I have does not have the optional heat shields (rear or bottom), so I want to fabricate protection for the wall (to cut clearances) and need to do something for the hearth (since I'm on wood subfloor).

I want a raised hearth, so I'm thinking of doing 2x6 framing with 5/8 sheathing on top. Then 2" cement board strips doubled up to give me spacers for a 1" air gap, two 1/2" cement boards on top of that & then either thin brick or ceramic tile mortared in.

I have a couple questions before I go put in for my permit:

1. I've seen references to using 22 - 24 gauge sheet metal when the hearth material is loose. Since I'm going to mortar the top layer in, I'm thinking I don't need this. Any reason for me to want to add a layer of sheet metal for the hearth?

2. For the wall, I'm spacing out two sheets of 1/2" cement board 1" from the wall & then the same brick or tile facade used for the hearth. I would like to seal up the sides (vertical), but leave the top & bottom open for ventilation. Since I'm going to have ventilation under my hearth, could I use that to "feed" the airspace for the wall? In other words, the top of the wall protection will be open, and the bottom will run flush to the hearth - the airflow will start at the front of the hearth, proceed under the hearth, and then up the wall. I'm just thinking aesthetics and trying to conceal the 1" air gap at the bottom of the wall protection and of course, stay safe. This would also give some vertical support to the wall protection, since it would be resting directly on the hearth.

Has anyone an install similar to this (or thoughts as to good/bad idea)?

Thanks in advance for any advice/feedback!

 

[fossil]

There's a lot involved here, but the very first consideration is whether or not the manufacturer's installation instructions and clearance to combustibles requirements allow for clearance reduction. The hearth protection requirements for the stove without a bottom heat shield should be clearly spelled out, as should the required clearances from sides and rear without heat shields. If the manufacturer doesn't mention anything about allowable clearance reductions, then you can't reduce the clearances. Check the book very carefully and thoroughly, then get back with us and we can discuss your options. If reductions are allowed, some of your ideas sound real good. We could also use more info on the install location...corner, or along a wall? What stovepipe are you planning to use, and have you figured the required CTC for that into your plan? Rick

 

[OldDedHed]

Retired fire chief here, done hundreds of wood stove inspections--I'd approve the install as you describe it without the sheet metal, and your air circulation idea sounds appropriate to me. I'm not familiar with the stove but I am assuming it sits on some sort of legs. Final check would be to check the install instructions for the stove, if you have them. Manufacturer's recommendations are almost always accepted by FD's and insurance companies.

 

[mjjochen]

Thanks for the replies. I thought my initial post was getting a little wordy, so in trying to keep it short I obviously left out some important info:

The stove sits on 6" legs. It is a corner install, but the corner is beveled at a 45. For clearances, I'm treating it like a parallel install - since those require more distance. The hearth is 6' wide by 5' deep. 18" from the front of the stove to end of the hearth.

Single-wall stove pipe to triple wall class A chimney pipe (ceiling box, radiation guards through the attic, etc.). Straight vertical shot from the stove flu collar to the chimney. 17 feet of chimney in all. Chimney will be enclosed in a chase once through the roof deck. The information with the pipe I'm considering states 2" CTC.

The installation instructions state that with no heat shields, clearances are 24" to rear wall, (15" to side wall for corner installation). With a protected surface, clearance decreases to 13" to rear wall (8" to side walls for corner). I want to install 20" to rear wall & 20" to side walls. The protected wall will give me a couple inches to spare there.

The only language in the instructions about floor protection are that for any floors that are not non-combustible, a heat shield should be used and that loose hearth materials should not be used - mortar them in place. The hearth should be a minimum of 31" wide by 42" deep. So I'm not sure if I can fabricate a heat shield or if I need to track down something stock from vermont castings.

Thanks again! Cheers, -m

 

[fossil]

For the wall clearances, the key words there from the manual are "protected surface", which means that if you construct a wall shield properly of non-combustible materials with a 1" ventilated air space behind, then you can go down to that minimum clearance. If the manual gives no specific requirement for insulative property of the hearth, but only refers to it being non-combustible, then you can pretty much build it any way you want to so long as the top surface of the required side/front/rear clearance area is something that won't burn. Rick

 

[mjjochen]

Thanks for the feedback - I'm ready to head down to the township to get the build permits now. Just can't wait till October to start burning! -m