Hi,
I've mined the Wiki, Main Informational Articles, and threads (including Dakotas Dad's construction photolog), and have come up with a hearth design I'd like you to check.
My goal is to build a hearth that will be compatible with virtually any stove I might want to put on it, in terms of insulation, non-combustibility, and load bearing. I want to do it right and do it once. I want to surface it with 12" marble tile, flush with my existing floor. It will be in a new bump-out, and I can position the new joists at whatever height necessary for the floor system above.
My main concern is making a subfloor out of noncombustible materials that is strong and rigid enough to ensure the tiling does not crack under heavy load, since the usual rigid subfloor material is flammable plywood. So I need to make a solid, non-combustible design.
Here is my strawman design, from bottom to top.
1. Wood floor joists.
2. Sheet metal (to retain noncombustible rockwool-type insulation)
3. Metal 2x4 studs, laid perpendicular to wood joists, long axis vertical, 12" OC
4 Fill with non-combustible insulation
5. Wonderboard or other non-combustible underlayment --suggestions for type and thickness?
6. Mortar to glue two layers of underlayment together -- suggestions for type?
7. A second layer of Wonderboard or other non-combustible underlayment, adhered to first --suggestions for type and thickness?
8. 12" square marble tile
Does this sound like a hearth that would work with virtually any stove?
As I said, I'm particularly concerned that the underlayment will be stiff and strong enough to support a heavy stove without cracking. It looks like Dakota's Dad didn't have any problems with his Heartstone, and his dog liked it too.
Would another layer of sheet metal, screwed on top of the metal studs beneath the cement board layers be advisable for greater support?
All suggestions appreciated! Thanks, and happy burning.
I've mined the Wiki, Main Informational Articles, and threads (including Dakotas Dad's construction photolog), and have come up with a hearth design I'd like you to check.
My goal is to build a hearth that will be compatible with virtually any stove I might want to put on it, in terms of insulation, non-combustibility, and load bearing. I want to do it right and do it once. I want to surface it with 12" marble tile, flush with my existing floor. It will be in a new bump-out, and I can position the new joists at whatever height necessary for the floor system above.
My main concern is making a subfloor out of noncombustible materials that is strong and rigid enough to ensure the tiling does not crack under heavy load, since the usual rigid subfloor material is flammable plywood. So I need to make a solid, non-combustible design.
Here is my strawman design, from bottom to top.
1. Wood floor joists.
2. Sheet metal (to retain noncombustible rockwool-type insulation)
3. Metal 2x4 studs, laid perpendicular to wood joists, long axis vertical, 12" OC
4 Fill with non-combustible insulation
5. Wonderboard or other non-combustible underlayment --suggestions for type and thickness?
6. Mortar to glue two layers of underlayment together -- suggestions for type?
7. A second layer of Wonderboard or other non-combustible underlayment, adhered to first --suggestions for type and thickness?
8. 12" square marble tile
Does this sound like a hearth that would work with virtually any stove?
As I said, I'm particularly concerned that the underlayment will be stiff and strong enough to support a heavy stove without cracking. It looks like Dakota's Dad didn't have any problems with his Heartstone, and his dog liked it too.
Would another layer of sheet metal, screwed on top of the metal studs beneath the cement board layers be advisable for greater support?
All suggestions appreciated! Thanks, and happy burning.
