Help! Building a woodstove hearth using flagstone

[wootey74]

Hi,
I am a homeowner who wants to build a Flagstone hearth for a wood stove in the corner of my living room. I have got a good start but could use some good advice to get the job done.
I took down the drywall all the way to the ceiling, added some insulation,built a platform on top of the hardwood flooring and covered it all with concrete board.
Now I'm ready to start putting up my stone.
The flagstone i chose is about 3/4" thick and is very brittle. I'm worried now that maybe the stone will not be solid enough.
I also would like to know what would be the best adhesive choice when using flagstone on concrete board in this possible high heat situation.
Any suggestions,advice,or links would be greatly appreciated.
Thanx,
Wootey

 

[00Buck]

Wootey,

Sorry no suggestions. But your not alone. My father is starting the same project in his basement. He just brought down 4,300 lbs of flagstone in his basement for his hearth.

 

[pen]

I would start by looking in your manual for the stove and determining what the required hearth pad r value is for the stove. Then you can use a chart such as this which I found at (broken link removed to http://chimneysweeponline.com/horvalue.htm) to determine how thick you need to go w/ different materials to overlay a combustible material.

Remember to only use materials that are certified for hearth installation such as original durock.


Material Thickness R-Value
Ceramic Board ( Micore 160 ) 1/2" 1.270
Ceramic Board ( Rescor 360 ) 1/2" 1.110
Ceramic Board ( Fiberfrax Duraboard LD ) 1/2" 1.100
Ceramic Board ( Micore 300 ) 1/2" 1.030
Common Brick 4" 0.800
Common Brick 2-1/4" 0.450
Gypsum or Plaster Board 1/2" 0.450
Cement Board ( Wonderboard ) 1/2" 0.200
Cement Board ( Durock ) 1/2" 0.200
Cement Board ( Hardibacker 500 ) .42" 0.200
Cement Board ( Hardibacker ) 1/4" 0.130
Limestone 1" 0.153
Cement Mortar 1/2" 0.100
Slate 1" 0.100
Concrete 1" 0.095
Marble 1" 0.090
Granite 1" 0.083
Ceramic Pavers 1" 0.080
Flagstone 1" 0.079
Sandstone 1" 0.079
Ceramic Tile 1/4" 0.020

 

[r_d_gard]

I just finish this. After reading the previous posts I wasn't sure if you meant a wall or a floor. I put 1" Copper Bay flagstones through my 1/2" wood floor (the wood floor was laid over concrete) I went back and forth over whether I should use refractory cement or not or type "S" mortar. In the end, I went with premixed mortar brough in a 5 gallon bucket from home depot, I can lay tile very well, yet I am just slow, the aditives in the mortar allow for a longer set time. I have also tiled wall with the stuff as well and have never had a problem. With 20/20 hindsight I think I made the right choice. I have measured the temp and I think that the rock won't crack or split because of the temperature variations and the mortar won't either as the rock is a good insulator. Anyway the attached photo shows what I ended up with. If you are doing a floor I can either send you more pictures.

Let us know how it turns out

 

[Shari]

I just finish this. After reading the previous posts I wasn't sure if you meant a wall or a floor. I put 1" Copper Bay flagstones through my 1/2" wood floor (the wood floor was laid over concrete) I went back and forth over whether I should use refractory cement or not or type "S" mortar. In the end, I went with premixed mortar brough in a 5 gallon bucket from home depot, I can lay tile very well, yet I am just slow, the aditives in the mortar allow for a longer set time. I have also tiled wall with the stuff as well and have never had a problem. With 20/20 hindsight I think I made the right choice. I have measured the temp and I think that the rock won't crack or split because of the temperature variations and the mortar won't either as the rock is a good insulator. Anyway the attached photo shows what I ended up with. If you are doing a floor I can either send you more pictures.

Let us know how it turns out

I see you have your wood piled next to the stove - do you have it placed outside your combustible clearances?

Shari

 

[woodracerx]

Rayza where did you get the flagstone from. I need some hearth stones close to that color

 

[r_d_gard]

Hello,

Shari, the wood is only there for the photo, I store my wood just outside the back door to the left of the fireplace. I'm sure the wood was there too long I would end up with spontaneous combustion.

Woodracerx, the stone is called Copper-bay, I purchased it from a company called Charles Luck Stone (have a look at the attached link
(broken link removed)) It was very easy to work with and the cost of the stone was just shy of $200. The colors range from a rather light silvery color to a deep copper color.
I hired a table saw the day I cut the stone and I am glad I did. The diamond blade went through the stone like a hot knife through butter.