Englander hearth pad clarification

[Thomas138]

Hello,

I have been reading many threads on here about hearth pads/floor protection and am hoping I can find some clarification to my problem. We just got an Englander 13nch to put on the main floor of our house. Previously, our stove has been downstairs on a concrete slab so this is our first time building a hearth.

Here is the confusion, the manual states that the pad must be on a 1" thick non combustible mill board or a durable equivalent. We used 1" plywood with two layers of 1/2" Durock with thin set and ceramic tile over this with the understanding that 1/2" Durock equivalent to 3/8" non combustible mill board as told by the folks at the hardware store. Also, it suggests a k value of .84 and a single sheet of Durock has a k value of .84. However, the manual also states that the "durable equivalent" should have an R-value of 2. So now we are trying to decide if we need to add roughly 6 sheets of Durock over the base we already have and tile that again to meet the R value even though we have more than adequate suggested k value and non combustible thickness. I hope this is clear, the manual just seems to have conflicting information that I can't quite understand.

Thanks for your help!
Thomas

 

[begreen]

Did you use Durock NexGen? If so it has an R value of .39, so 5 sheets would get you close enough. Many do a bottom layer of 1/2" Micore @R=1.03, first to build up R value.

 

[BillT]

You may have read my recent post, but I have an Englander 13-NC and I am planning on 5 sheets of Durock New Generation, then Ceramic Floor Tile. I would like to put in Micore, but I can't find any locally, last I checked anyway.

 

[Thomas138]

Thanks for the help. We could not find micore locally. we just added 3 more layers of Durock next gen as well as mortar and tile so we will be coming in higher than suggested r value.

Thanks again
Thomas