need to build a hearth for new stove

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FrankenCub

New Member
Feb 3, 2009
8
Southern Tier, NY
Hi guys...new member kinda confused. I am getting a USSC model 2015 for our mobile home and called our local building inspector to see if there are any specific requirements for our town. The only thing he could offer was to go by the manufacturers specs. Ok...not that big a deal. The manual for this stove only says it needs to be rated R-1 which I thought was pretty low. Our local building supply has never heard of Micore 300 and they don't carry wonderboard any more. They only carry hardie backer board which is only rated at .13R which I thought wasn't very good. I searched the net and found the Micore but no one even close caries it. I really need to keep the cost reasonable and hopefully not real thick. Any advise ?
 
You have lots of options... One option is these guys: http://www.industrialinsulation.com/board_insulation.htm - looks like they may be in your area (tho I can't really tell where Southern Tier is).

The real key is to get AWAY from the Home Depots and local hardware stores, and find a real building supply company. They will sell mineral wool insulation boards.

One other option is to use air space from plain steel studs laid on the face, mortared to a suitable base. Hardi Backer is not recommended, but there's a lot of debate on the subject, to be honest. I'd expand your search to find a store that does sell a concrete-based board - it's far less controversial...

Finally, a great link to R-value data: http://www.chimneysweeponline.com/horvalue.htm

Good luck with your search, build, and burning!
 
Thanks for the reply dawg. I checked your links out, that mineral board looks like the deal. They are about 4 hours away though. We really don't have any good building supply companys that I know of here in Broome Co. I have found that Home Depo does sell Durock which is a cement board. I happened to be looking through Craigs List a little while ago and found a contractor going out of buisness, which is too bad, that has a huge supply of steel studding he's liquidating so an email went out to him. Also found a guy selling roofing slate he saved from an old house. So, I should be safe putting the cement board over the studs and the slate will look good.
 
cement board is not concrete board. Big difference. Wonderboard/Durock = Concrete. Hardi-backer = cement. Cementitious, actually. Has organics / cellulose in it. Not necessarily flammable, but could be prone to outgassing or other less-than-desirable actions in a hearth application.

I used Wonderboard and metal studs for my hearth.

I wouldn't use roofing slate for a hearth. Too fragile and unforgiving. Just get some tile. HD sells 12" and even larger tiles they sell for well below $1/sq ft.
 
Ok, thanks for the correction. It is Durock they sell. I can see why the Hardi board is no good then. Can I get away with a single layer of Durock or should I double it ? I didn't realize the roofing slate would be that fragile, thats too bad cause I like the looks. There is however someone on Craigs List that also has new leftover tile from either Lowes or Home Depo, forget which, their trying to get rid of. Think they have 12" and 18" in two different colors. Both floor tiles, one is indoor other is either. I'll send them an email tonight. I had 6 pieces of marble that was rejected from a job site, not polished very well, that I ended up with. They were 3"sq. I thought I would try to get some shine to them, I tried every polishing compound I had with my buffer and got nowhere. I should have saved them. They would have been good for this. Well...other than they were heavier than heck.
 
metal studs would do the job! i didnt want to spend the money for them so i used hallow, 4" bricks on top of Durrock. the hallow bricks allow air to flow between them (when lined up together). i went to lowe's and got 3 boxes of multicolor slate and put on top of the brick, looks great. total in hearth pad $90.00
 
FrankenCub said:
Can I get away with a single layer of Durock or should I double it ?

Not exactly sure why you are asking this - 2 layers alone? or two layer over a mineral board product? or two layers over a steel-stud airgap?

2 layers of 1/2" Durock alone are only about R 0.4. See the list I gave you for R-value data: http://www.chimneysweeponline.com/horvalue.htm

If you need R 1.0 minimum, you have a ways to go. You CAN just stack 5 sheets but boy - sounds like a lot of weight... I went the steel stud route, myself...

See attached images. From the floor up: 1/4" Hardi, 1/4" Wonderboard, steel studs, 1/2" Wonderboard, cheapest 1/4" ceramic tile HD sells, 500 lb stove. It's freestanding - all mortared together - only screws are holding the top 1/2" Wonderboard down to the stud faces. No cracks yet! Cost about $150 total, and I think that included the tile cutter, face tiles, trim, mortar, and the saw blade for the steel studs. R value is a little over 1.2 IIRC.

Sharp edges on those steel studs - be really careful working with them.
 

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Sorry, should have said 1 layer of 1/2" Durock or 2 over the steel studs with vented air gap. I seem to get more vague as the night progresses :)
I don't think I'm going to find the mineral board near me.
 
Go for the Durock, two layers 1/2" on top of the studs should be fine. What about to the rear?
 
As a suggestion, take some pics of everything before it's covered with tile; just in case the insurance, bldg inspector, etc. wants them. We don't have inspections here, but our insurance form had a lot of questions and some of them were easier to answer with a picture. Good luck and enjoy!
 
Good idea with the camera, I take pics of everything but didn't think of that. Our inspectors here don't seem to be to bright, he sounded like he didn't know how it should be done which lead me here. Oh...I will defenantly enjoy the wood heat. Buying kerosene makes me sick. That and I grew up with wood heat as a kid, nothing like coming home from a long night snowmobiling at below zero temps and sitting next to the wood stove...aahhhh
 
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