# Fireproof Board



## HARRY BARKER (Jan 11, 2010)

I need minimum 3/8" thick board to go under woodstove to meet code...building inspector forgot the name of the stuff but said it was like homasote and could be cut with a sheetrock knife...anyone know the name of the stuff? i have searched but all i come up with is the fancy stove boards/hearth type things.


----------



## Wife'nHubby (Jan 11, 2010)

Durock

Shari


----------



## HARRY BARKER (Jan 11, 2010)

nope....we talked about that...he said it was flexible like homasote....thanks though..


----------



## Wife'nHubby (Jan 11, 2010)

Then it must be Micore - but it's hard to find.

Shari


----------



## Torin (Jan 11, 2010)

Homosote Wall Shield?


----------



## Wife'nHubby (Jan 11, 2010)

Edit: The only other one I am aware of is hardibacker - but apparently the manufacturer has changed the composition and now hardibacker is not recommended.

Shari


----------



## Torin (Jan 11, 2010)

I can also remember a product called eterboard. I don't know if it still around.


----------



## JFerg65 (Jan 11, 2010)

It is called micore and if you google it, you will eventually find the company and can do a dealer locator. Many dry wall whole salers have it. It is soft and you have to put hardi backer or durarock over it. It comes in 1/2 thick sheets 4x8. I think I paid about 80 cents a square foot. 

You can't get anything with a higher R value. I think it has an R value of 1.03 or something like that. I ended up with 1 inch of micore 1 inch of hardibacker and then my finished tile on top, well over the R-Value of 2 they look for.


----------



## turnkey4099 (Jan 12, 2010)

Used to be a product "Wonderboard" - fibreglass mesh and cement - rigid. Why would you need a flexible piece under a stove?

Harry K


----------



## Marc (Jan 12, 2010)

Marinite would suit your needs. Might be able to get it through Grainger or someone like that.

http://www.industrialinsulation.com/marinite_board.htm


----------



## Marc (Jan 12, 2010)

You can also get Kaowool in board form.


----------



## kfhines (Jan 12, 2010)

I used two 1/2" x 48" x 48" sheets of MARINITE 1 from ARMIL/CFS INC. with dura rock above and below then tiled over the top for a flush hearth. It was not cheap @ $575. shipped from Illinois! It is a ridged furnace board that can be cut with a sheetrock knife or circular saw just don't breath the dust.
I could not find or locate any body locally that would order Micore for me, so I was forced to find another alternative.
So far (2 months) the tile and grout have not flexed enough to crack with a 689# stove sitting on it.








kfhines


----------



## blades (Jan 12, 2010)

I just purchased a sheet of PCS cer-wool HP board 1" x 24x36 good for 2100 deg. $60. got it from a local refractories supply out fit. I needed it to replace the insulation panels inside the stove above the secondaries. If you framed it with angle iron and set your tiles the old way you would be good to go. Probably the same a KAO board just different mfg.


----------



## JFerg65 (Jan 12, 2010)

The Micore is soft yes, but provides unequaled R-Value of anything out there. The Micore does require another substrate such as hardiboard, wonderboard, or durarock in order to provide the platform for the finish application. The hardiboard distributes the weight with no issue. 

I took no chances and overbuilt my hearth in the R-Value department. I've seen some hearths that frankly, I would have a hard time sleeping at night knowing I had a fire burning in my stove.


----------



## demographic (Jan 12, 2010)

Wife'nHubby said:


> Edit: The only other one I am aware of is hardibacker - but apparently the manufacturer has changed the composition and now hardibacker is not recommended.
> 
> Shari




Oh, well there goes my recommendation anyway as I was going to suggest half inch thick Hardibacker.


----------



## JFerg65 (Jan 12, 2010)

I just went to the hardi websight and it still appears you can use it. It does transfer heat but will not burn. Any thoughts?


----------



## blades (Jan 12, 2010)

I do not know or remember which kind ( one of the cement boards though) that they are adding foam beads to, to reduce the weight. Doesn't do much for fire protection. Maybe it is one of durarock brands.


----------



## demographic (Jan 12, 2010)

JFerg65 said:


> I just went to the hardi websight and it still appears you can use it. It does transfer heat but will not burn. Any thoughts?




Its possible that the Hadribacker we get in the UK is slightly different than what you get but I was using some recently and put a bit on the fire to see how it held up.

It didn't burn at all but did de-laminate after it had been in a fire for a good length of time, I wouldn't worry about that if I were using it as long as it wasn't actually *in* the fire all the time.

Another cement based board that I have clad some sections of a building with was called Marley Eternit board, THIS Wiki page suggests it is suitable for use as fire protection but that wasn't what I used it for so can't comment much.


----------



## Billy_Bob (Jan 12, 2010)

I used two sheets of Micore under the ceramic tile floor and that exceeded the woodstove manufacturer's specifications for R-Value. (And the inspectors!)

http://www.gypsumsolutions.com/htmlID/micore.asp


----------



## JFerg65 (Jan 12, 2010)

Billy Bob

How in the hell did you get the tile to not flex and crack and to stay in one place! That stuff is so soft and flexible.


----------



## davec (Jan 12, 2010)

Foamglas?


----------



## Billy_Bob (Jan 12, 2010)

JFerg65 said:


> Billy Bob
> 
> How in the hell did you get the tile to not flex and crack and to stay in one place! That stuff is so soft and flexible.




I was thinking... How did I do that?

Ahhh I remember! I put cement board or tile backer on top! (Forget exactly what you call it?) Then the tile on top of that.


----------



## JFerg65 (Jan 13, 2010)

Billy Bob

That is exactly what I did as well. The hardest part of that job was actually driving the hour to the drywall wholesaler to buy it. 

My suggestion to anyone out there getting ready to do or redo their hearths is to do your research and don't short cut the R-Value requirements by the manufacturer or the inspector if one is involved. Also don't forget to properly seal the edges where/if the hearth butts up against a wall or existing firebox.


----------

