HEARTH PAD

[loneeagle15]

We ordered our mansfield soapstone stove and need to put in a pad my wife wants to tile a large area my question is it needs a r 1.01 under the stove will 1/2" cement board and tile be ok over a wood underlayment or should I go with 1"?
Thanks JD

 

[MountainStoveGuy]

if you go to www.hearthstonestoves.com and download the manual, it will have the r value's for various materials. If i remember correctly cement board is a .20 and tile is a .01.

 

[bcnu]

You can find lots of good hearth building info by using the "search" feature. That's where I started. Now, I'm in the process of putting in a floor level hearth. I need a minimum of R 1.2. 1/2 inch of Micore 300 has an R value of almost 1.1. I will top it off with wonderboard, durock, or cement board and tile. (I may even double the Micore just to increase the R value if ever needed later.) Good luck

 

[jjbaer]

We ordered our mansfield soapstone stove and need to put in a pad my wife wants to tile a large area my question is it needs a r 1.01 under the stove will 1/2" cement board and tile be ok over a wood underlayment or should I go with 1"?
Thanks JD

1/2" cement board like Wonderboard won't do at 1/2" thickness....nor will 1 inch or even 2 inches.......Wonderboard has an R of about 0.4 per inch so you'd need a little over 2.5" thick to get an R of 1.1 and tile has virtually no R-value (1/4" thick tile only has an R-value of 0.02). So....if you want a thinner pad, use Micore (Micore 300 has an R-value of 2.33/inch and Micore 160 has R-value of 2.86/inch) topped by a thin layer of Durock or cement board, then tile.

Example:

1/4" plywood on bottom
3/8" Micore 160 for next layer has R-value of 1.07
1/4" cement board next has R-value of about 0.1
1/4" tile on top has R-value of 0.02

Total R-value of pad = 1.19, total pad thickness = 9/8" thick. You can use thicker plywood (1/2") and cement board (1/2") to make it stiffer if you want. Doing so gives you an R of 1.29 and a thickness of 13/8"

You can come up with other combinations using Micore 300 and other thicknesses of various materials

 

[ansehnlich1]

I just built a hearth for a stove.

Durock is .26 r per half inch. Thus, 2 inches (4 half inch sheets) went down first on my subfloor, and that was topped with brick, which is about .20 r per inch, giving me a grand total of 1.4 r value.

You can find r values of some hearth materials here: https://www.hearth.com/articles/64_0_1_0_M1.html

And, you can see a pic of my hearth in this thread: https://www.hearth.com/econtent/index.php/forums/viewthread/6525/

 

[loneeagle15]

Thanks for the comments thats why I'm here I do not want to burn down my house I have to watch the height because of an exterior door thought came to me last nite has anyone used welding blankets under the cement board
Thanks JD

 

[colsmith]

Hello, I am guessing that the exterior door is not within the required hearth pad high R-value area. Could you do a slightly raised area within the official hearth pad, and then have a little downward transition, say small transition tiles around the edge, and then a wider tiled area that matches the hearth and doesn't mess with the door opening? Would look nice, but you might have the problem of running your feet into the raised area, but I would think you wouldn't be walking that close to the stove much anyway?!?

We went the other way, raised our hearth up really high. Our hearth R value was similar to what you need, we did the plywood - Micore 300 - cement board - ceramic tile route, just up in the air on a framework. Photos under the Perfect Picture forum, hearth and Hearthstone Phoenix thread.

 

[G-rott]

Can you get under the hearth area? I wanted to tile the entire floor w/o a step up at the hearth. I ended up cutting out the sub floor and sistering nailer to the joist and droping my sub floor down flush with the tops of the joist. This gave me the extra room I needed for my Micore and tile backer in the hearth area.

Garett