Help Building Hearth Pad for Insert

[bostonrob]

Hello all, new poster here and I really need help.

In my last house I had two Breckwell inserts (P2000I and P23). When we moved I saved both stoves and now having purchased a new house I would like to use one of them.

In my new house I have a firebox that the previous owners demolished the front of the hearth and closed in the box in the wall. I exposed the firebox itself and now am looking to build just a face that the insert will be set into.

I have seen people build a box in a wall and ran a pellet stove however I cant find ANY information on R Value of what the stove sits on.

Will I be able to get away with wood 2x6 construction holding up one or two layers of Durock and the stove sitting on that or do I need to frame in all metal studs 12 inches in either direction? Will one layer or Durock suffice or do I need two? There is NO information on this type of application that I can find.

 

[imacman]

Most people have used wood framing, then 1/2" cement board with tile or thin stone on top. Don't think steel studs are needed.

 

[Vognorth]

I built the one in my avatar out of 2x2's (spaced no more than 12" apart), with a layer of 1/2" OSB screwed to the top, then a layer of 1/2" cement board, and ceramic tiles...our stove weighs 305 lbs and I stand on the pad when filling it with pellets. It's rock solid. So whether you use 2x4's or 2x6's it'll be plenty strong enough and should provide the R-value you need. Our stove's manual simply stated "place on non-combustible surface". The base is typically luke-warm at best when the stove is running.

 

[bostonrob]

Thanks Imac. Vog, im not doing this for a free standing. This is a pellet insert that half of the rear will be in a masonry fireplace and half will be fitted into a 2x6 wall. I need to make sure there is not too much heat through the bottom if I butt my wood 2x6 up to the Durock or if I should just frame the whole thing out of metal.

 

[Harvey Schneider]

Check the manual for your insert. It will tell you what clearance to combustibles is required. Metal framing doesn't really help, it's a good thermal conductor in an enclosed space.

 

[bostonrob]

The Website gives 5 Inches of clearance. That does not state that the 5 inches includes going through a section of masonry and such. ????

 

[Harvey Schneider]

The Website gives 5 Inches of clearance. That does not state that the 5 inches includes going through a section of masonry and such. ????

I don't know what insert you have, but that is usually given as clearance to a combustible surface. The cement board is clearly not a combustible surface, and the back of it won't be any hotter than the front. Is the issue that you don't have 5 inches available?

 

[imacman]

I don't know what insert you have.....

In the OP's first post: "two Breckwell inserts (P2000I and P23)"

 

[Dinger]

I don't know what insert you have, but that is usually given as clearance to a combustible surface. The cement board is clearly not a combustible surface, and the back of it won't be any hotter than the front. Is the issue that you don't have 5 inches available?

I'm not 100%, as I'm not code enforcement, but the way it was explained to me here was a non combustible cannot be mounted "out of" the clearance range to a combustible "in spec", or it becomes considered a combustible. Not sure if I worded that properly but I bet you understand. That kept me from rocking my alcove. My side clearance is 7" spec'd 6", rock would have added 2" nominal taking me to 5", thereby encroaching spec'd clearance.

Again it might be wrong, but it saved me $1000 regardless.

 

[Harvey Schneider]

My side clearance is 7" spec'd 6", rock would have added 2" nominal taking me to 5", thereby encroaching spec'd clearance.

That sounds right