Building My First Hearth Pad

[CT Cowboy]

This is my first post and I need as much advise as I can get. This Forum as been so helpful. I hope I can get some additional expert advise with my hearth. I just bought a sheet of 3/4" Micore 300. Since 1/2" Micore has an R value of 1.10, can I assume that 3/4" has an R value of 1.65? I intend to put a Jotul F500 Oslo on this hearth pad. The stove manual only lists a recommended R value for the hearth if the stove is going to be in an alcove (1.6). It has no specific recommendation for being in the center of a wall---open on the front and sides. My thought was to put the 3/4 Micore, topped with 1/4" Durock, and topped with 1/4" porcelain tile. Will that be sufficient protection? Or do I need 1/2" Durock? This is all going to be screwed down onto my oak hardwood floor. I want as thin a hearth as possible so people don't trip over it. The room is not large and the wall to wall carpeting will run right to the hearth. I will be grateful for input from all of you experienced wood burners and hearth builders. Thanks!

 

[begreen]

All you need is a continuous non-combustible surface. You can skip the micore entirely if you want to keep the hearth thin. But use thicker durock for sure. You don't want any flexing under the stove legs.

FWIW, people seem to trip more on something that is just a little above floor height, than something that is clearly higher.

Floor Protection
Floor protection under the stove must be constructed of a noncombustible
material for protection from radiant heat, sparks,
and embers.

Individual sections of floor protection must be mortared
together to prevent sparks from falling through to combustible
materials. Any carpeting must be removed from under the floor
protection.

 

[nshif]

Forget the micor, overkill. Just put down a 1/2" layer of Duroc and the tile. You only need the R value for an alcove the way I read it. And you might put down some thinset below the Duroc just for better grip, Youll have it anyway for the tile. Now if you think you might change stoves someday to one with an R value requirment go ahead and put the micore down, doesnt hurt to have more protection then required.

 

[CT Cowboy]

Thank you both for your responses. I have just been reading so much about people using Micore and trying to reach specific R values, I thought that it was mandatory to achieve a certain level of protection. The stove is on approximately 6" legs and I just want to keep things safe. So the radiant heat will not penetrate 1" of protection? I know there will be protection from sparks and embers, but the radiant heat is what I have no idea about. Thanks again!

 

[begreen]

It varies from stove to stove. Best to follow the manual's installation instructions.

 

[jeffman3]

My stove only called for an R factor of .6, but I built for 1. Extra protection never hurt anybody! I would rather know, that I know, that I know, my family is safe, if you catch my drift. The manuals list minimum requirements, not do not exceed. More will only help you sleep at night. I would use everything I had.

I built up with 5 layers of 5/16 Duroc with thin-set between each layer and 1/2 inch under my tile. (my floors turned out to be not as level as I thought, didn't think to check that before I built the base.) I ended up with about an R factor of right at 1 and I sleep well knowing that I don't have anything to worry about.