I've got an Avalon Ranier 45 coming (which will sit 10 inches in front of the fireplace) and so I needed to extend my hearth from 18 inches to 26+ inches.
My existing hearth was bricks that were raised about 1/4 inch from the floor. I've removed the bricks and four courses of oak floor in front of the hearth and my plan is to set one single piece of 60 inch by 27 inch bluestone. It will rest partly on the sub floor and partly where the bricks used to be. At this height, the stone will be 1/4 inch raised from the adjacent floor which is how I want it to be.
In order to keep the bluestone from cracking I realize that I need to make the subsurface extremely level. Also, since this is an insert that is sitting 10 inches onto the hearth, I realize that whatever I put under the bluestone (where the bricks used to be) must be able to resist the heat of the stove.
The Avalon manual seems to be silent on the issue of materials to use under it. The only requirement is that the hearth , "Must be non-combustible 1/4" thick insulating board with a thermal conductivity of K = 0.72" but I'm assuming that this is referring to the part of the hearth that is in front of the stove - not directly under it.
Any thoughts on what materials I should put under the bluestone that will 1) enable me to make a level surface with the subfloor, and b) will provide enough R-value to be safe?
Also, I was thinking that once the subsurface is level, I wouldn't even use mortar or adhesive to set the bluestone. Do I need to use some adhesive/mortar?
Thanks!
My existing hearth was bricks that were raised about 1/4 inch from the floor. I've removed the bricks and four courses of oak floor in front of the hearth and my plan is to set one single piece of 60 inch by 27 inch bluestone. It will rest partly on the sub floor and partly where the bricks used to be. At this height, the stone will be 1/4 inch raised from the adjacent floor which is how I want it to be.
In order to keep the bluestone from cracking I realize that I need to make the subsurface extremely level. Also, since this is an insert that is sitting 10 inches onto the hearth, I realize that whatever I put under the bluestone (where the bricks used to be) must be able to resist the heat of the stove.
The Avalon manual seems to be silent on the issue of materials to use under it. The only requirement is that the hearth , "Must be non-combustible 1/4" thick insulating board with a thermal conductivity of K = 0.72" but I'm assuming that this is referring to the part of the hearth that is in front of the stove - not directly under it.
Any thoughts on what materials I should put under the bluestone that will 1) enable me to make a level surface with the subfloor, and b) will provide enough R-value to be safe?
Also, I was thinking that once the subsurface is level, I wouldn't even use mortar or adhesive to set the bluestone. Do I need to use some adhesive/mortar?
Thanks!