I've used a lot of Kaowool products repairing coke ovens here in the Pittsburgh area. Its great stuff, and I used the 2 inch blanket to insulate around my wall pass through (thimble). As far as building a hearth pad with it, I guess it would depend on your homeowners insurance requiring a UL listed hearth pad or not.
I have the Pleasant hearth medium, 1800sq ft. stove, it requires r=2.0 I currently have a 1" slab of marble and 3 sheets of 3X5 next gen. durock below the marble, but still falling short. Seems crazy.
That would be great news if it was fine the way it is. I did have my engineer buddy review my hearth design, and well, he said you could park a semi on it if the sub floor would hold.lol. it would be nice to settle with the way it is though.Hold off, your hearth may be fine. I heard from Pleasant Hearth yesterday. They are investigating the change from this spec just a couple years ago.
Note, an insulation blanket is not going to work as well under the weight of stone and cement board. It depends on air spaces in the blanket for it's insulating properties. They are lost if it is compressed. You need a solid, firm product that is not going to compress like kaowool board, mineral board, micore or similar product. I'm not sure about kaowool paper, it would seem like you would need several layers, but maybe it would work?
Good news. I heard back from Pleasant Hearth today. This is what they had to say:That would be great news if it was fine the way it is. I did have my engineer buddy review my hearth design, and well, he said you could park a semi on it if the sub floor would hold.lol. it would be nice to settle with the way it is though.