Is It OK To Use Stove Over Durock Without Tile?

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CWYfire

New Member
Nov 21, 2008
26
NE Oklahoma
I have yet to find the tile deal that I'm ha ppy with. But I do have my 1" Durock heat shields on the walls and Durock covering the wood subfloor, as per specs.

Question: Is there anything wrong with pulling a couple coats of thinset on all of the seams of the Durock so no coals can penetrate to combustibles, firing up my stove and using it until I can find the tile I like? We are having some really cold spells in the Midwest and I would like to be heating with wood right now.... Just don't wanna burn down my house...

Thanks for your help
Ed
 
as long as the heat shield has gaps in the top and bottom to allow air to travel through the 1 inch air space then it should not be a problem. the tile itself ads very little thermal barrier or r-value. it's primarily for aesthetics. in fact many heat shield are just a solid piece of metal which, on its own, adds close to zero in terms of a thermal barrier. it is all in that inch air space, which adds a sufficient thermal barrier between your stove and combustibles. when are you planning on, or have you already had the building inspector sign off on the project?
 
I'm in a rural town and wasn't planning on messing with calling the building inspector. I have built homes for almost thirty years and this is my own home so the advice I have gotten on here is going to be it. I have found the expertise here outstanding and feel confident in how everything is built thus far.

I was mainly concerned with the Durock on the floor and the potential of either heat or coals getting into any cracks or crevices to the plywood.

Is there a specific reason why I should have a building inspector approve my work? I am thinking like to sign off that everything was done to code for the insurance company and in case of a fire later?

Thanks
Ed
 
CWYfire said:
I am thinking like to sign off that everything was done to code for the insurance company and in case of a fire later?

Thanks
Ed
you got it, god forbid if you aver did have a fire, your insurance company will find any reason they can not to hand you hundreds of thousands of dollars. there are also a few other reasons as well. my cousin just recently sold his house and about 10 years ago he added a deck outside which was never approved or run through the building department. after he sold his house the new homeowners did not want the deck and since it was never approved he was required to spend 4 days tearing it down. he wasnt too happy about that.
 
btw if everything is up to code (which im sure it will be as this site is very thorough and informative), getting everything approved cost me 1 trip to the building department, 30 dollars, and to be home from 10-12 on a tuesday. not too bad considering what at could potentially save me.
 
From the practical side of life...
Durock seems like something that would be difficult to keep clean, (putting it mildly).
I assume you will place the stove for the winter, then take it back down, then tile, then put the stove back again?
If only you could tile now, it would save you a bunch of future work.
...just my observation.
 
Sounds like you are creating a bigger job for down the road. Hell, tile is dirt cheap at Lowes, HD you name it. I made up the base for my pellet rig in about an hour and the tile was the simplest part. Not much to it really if you size it right and I made the few cuts I needed with a 7"abrasive wheel on the table saw. Seems like moving the stove again, jacking it up or whatever later is going to cost you a dollar to save a dime time-wise down the road. U B SORRRRREEEEEEEE.................................. just wait and see.
 
Dura-Rock alone - as hearth protection - will not meet the required R-values cited in your owner's manual. I believe it has a rating of around .2 per INCH.
Most woodstoves that I've seen require an R-value of at least 1.2 - 1.5...That means you may have to have 7.5 sheets of Dura-Rock to meet spec...
If you can find some Micore at a local Hearth Shop, it comes in 1/2 x 20 x 72" sheets & has an R-value of 1.1 - 1.2...
You could put the Dura-Rock OVER the Micore & add thinset & tile & you'd meet spec.
Then again, we don't hear of too many house fires caused by hearthpad designs, but you might as well meet the specs & have the local building guy add his blessings!
 
To answer the OP, assuming the hearth value is correct, yes you can run the stove on the raw Durock temporarily. If you want to be extra safe, just put a sheet of metal over the unfinished cement board.

Hearth requirements vary dramatically from brand to brand. Many stoves simply require ember protection, others require fairly substantial hearth protection. The Century in question appears to want the standard 3/8" millboard or equivalent R=1.2. Durock is R=.26 so it would take 5 layers to achieve this R value. Micore or equivalent is much more efficient. An air space can also work well here.

Here's a link about the R value of a 3/8" millboard hearth requirement.
https://www.hearth.com/econtent/index.php/forums/viewthread/22089/
 
You have an owner's manual.

Does it require an R-value on the hearth? Many don't. If it does then we can tell you if the durock is sufficient for that.

Does your manual require the wall shield. The vast majority don't even require it. The stove can be surrounded by plywood so long as the plywood is outside of the minimum clearance to combustibles.

If your manual does not require a particular R-value for the hearth but instead requires a non-combustible ember protection. Then a single layer of durock, with proper joint sealing, certainly is non-combustible and continuous. I would run it.

Get a permit. I got one and it was easy. The benefit is that if your house burns down the fire department will often blame the woodstove. It's an easy target. If the woodstove, installed illegally without a permit, causes a fire then your insurance will reject the claim. Also, if you ever sell the house and they manage to burn it down and then their insurance finds that the install wasn't permitted then the you will still be liable for the house cost plus any inconvenience or restitution for the new owners.

What if someone dies in that housefire? Your fault. They'll find you.
 
I was reading the manufacture's specs calling for at least 3/8" mill board or equivalent thinking that 1/2 Durock would meet that requirement as an equivalent. Hmmm I better slow down here and hear a bit more about this.... Give me the scoop guys.
 
The specs and manual for my stove can be found at http://www.vermontcastings.com/content/products/productdetails.cfm?id=208

What the manual says about installing on a combustible floor is as follows:

Installation on a Combustible Floor

If the appliance is to be installed on a combustible floor or a combustible floor covering, it must be installed on a 3/8” (10mm) thick non-combustible millboard floor protector or durable equivalent. The pad must be installed beneath the appliance extending 18” in Canada and 16” in the USA. On any side equipped with a door and 8” on all other sides. In the USA the pad must cover any horizontal chimney connector runs and extend 2” beyond each side.

A grouted ceramic floor-tile surface installed per local building code is considered a durable equivalent.

Is this not saying that 1/2 Durock with tile is sufficient floor protection?

My stove is a pedestal type with an ash drawer under the firebox. Might that be why it seems there is less requirement for floor protection?
 
In the flyer titled CDW 300007 Date code prior to Aug 2007 states:

Unit must be placed on a non-combustible floor protection equivalent to 3/8" millwood. Consult your local building authorities for further information.
 
From what the manual says, the 1/2" Durock should be fine. Tape the seams with mesh tape and thinset. You could skim coat the whole thing with thinset but it would have a kind of rough finish and be hard to clean. I suppose if you wanted, you could paint it with high temp paint.
 
<> If the woodstove, installed illegally without a permit, causes a fire then your insurance will reject the claim. <>

Woodstoves CANNOT cause fires...fires are caused by the NUT holding onto the handle!
 
Cannot find a tile you like? Hmm. Anything will look better than durock with thinset smeared all over it. I would not set a stove on durock. The legs or pedestal would do a number on the material. Pick a base color tile, grout it down and start enjoying your stove.

Let's hear some insurance stories.

Peace
 
DAKSY said:
<> If the woodstove, installed illegally without a permit, causes a fire then your insurance will reject the claim. <>

Woodstoves CANNOT cause fires...fires are caused by the NUT holding onto the handle!

Yeah, electrical wires can't cause fires either unless some nut runs too much electricity through them.

If you elminate fires "caused" by electrical malfunction or woodstove malfunction, there aren't many left. Firemen always find something to blame which is why I get electrical and woodstove permits but no permits for plumbing.
 
OK guys you talked me into waiting and finding my tile. I was thinking it wouldn't be much effort to sit the stove back out. But after reading your posts it makes sense to find the floor tile and get that much down at the very least... I was hoping to find a deal on something expensive so this would be a focal point that would "POP" when you walk in the front door. Just seems like it is taking forever to get this thing ready to rumble.... Guess a little more patience would save me more work than I thought.... and these days I am not turning it out like I could twenty years ago.... lol Makes sense to just get it done right the first time and enjoy!

As far as tile goes is one kind better than another like porcelain better than ceramic or marble, etc.?
 
CWYfire said:
If the appliance is to be installed on a combustible floor or a combustible floor covering, it must be installed on a 3/8” (10mm) thick non-combustible millboard floor protector or durable equivalent. The pad must be installed beneath the appliance extending 18” in Canada and 16” in the USA. On any side equipped with a door and 8” on all other sides. In the USA the pad must cover any horizontal chimney connector runs and extend 2” beyond each side.

A grouted ceramic floor-tile surface installed per local building code is considered a durable equivalent.

Is this not saying that 1/2 Durock with tile is sufficient floor protection?

My stove is a pedestal type with an ash drawer under the firebox. Might that be why it seems there is less requirement for floor protection?

1/2" Durock (cement board) is not equivalent to millboard in R value. Millboard has a higher insulation value, see previous link. However, if your local inspector has given you the go ahead, then so be it.

Maybe Rick can give you a hearth temp for his Century
 
im sorry CWYfire when i read your original post it was late and i thought you were only referring to forging the tile on the wall. as that would not be difficult to tile after the stove is installed, i suggested no reason not to do it. now that i know that you were also referring to the pad itself, that would definitely be more difficult to tile after the stove is installed. dont know if its been said, but with what you posted from the installation manual, as long as it doesnt specify an r-value you must achieve, then one layer of durock alone would suffice and give you the 3/8 requirement. however since the big box stores have a wide variety of cheap tiles, i would suggest to just pick something up to make life a hell of a lot easier for you in the long run. (dont know if this helps but home depot seemed to have a better selection and cheaper prices than lowes. i got a walnut natural travertine tile for 2.99 psf. lowes was selling the same stuff for 6.99psf)

CWYfire said:
As far as tile goes is one kind better than another like porcelain better than ceramic or marble, etc.?

as far as this question goes.
hardness - porcelain is the hardest tile, then ceramic, then natural stone (can be scratched easily)
ease of installation - porcelain and ceramic both about the same, and natural stone is more difficult (needs to be cut with a wetsaw, has a tendency to break on the veins and is brittle, grout joints are usually very tight and shows unevenness of tile more. plus unsanded grout (tight joints) is a pain in the ass.)
ease of maintenance - porcelain and ceramic are about the same, natural stone is a bit more difficult (if you wish it can be sealed to prevent stains)

sry i did tile work for about 5 years. but anyway natural stone is a bit more difficult but i think it is worth the extra work, and if you have or can borrow a wetsaw, i suggest to just go for it. buy a few more than you think you'll need as you're going to break a few of them.
 
Rick could you give a hearth temp on your Century? Also what kind of heat does it throw off the sides?
 
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