Lowering raised hearth

[JonOfSunderland]

House built in 1969. Masonry fireplace. The fireplace is 29" high to the lintel, which is only a hair too short to rear vent a Jotul F55. Tall enough for an Oslo, but I'm still on the fence. My question is, what might I expect to find under that tile? Solid concrete fill? Rubble covered in mortar? Brick? I don't really want to completely remove the raised hearth for aesthetic reasons, just lower it enough to clear the pipe.

 

[mstoelton]

Usually filled with Brick, and mortared in place. It's going to be an all or nothing removal. may be able to rebuild it if you are careful. You can rent a demo hammer from HD to break it up (recommended). I just broke the tile top off of a similar hearth. Demo hammer took about 5 minutes. Found it filled with bricks mortared in place bricks standing on end.

I was thinking of lowering the hearth as well. Glad I gave up on that idea. You will need to understand that if you lower the hearth, that will not lower the bottom of the fire box. They are separate and that will mean that your stove will need to set completely outside of your fireplace.

 

[JonOfSunderland]

It's going to be an all or nothing removal.

I should be able to stop flush with the floor and not destroy the poured concrete (hopefully reinforced) cantilevered base, correct?

 

[mstoelton]

If the second photo is of the bottom of the hearth looking up, it may be one solid pour and it may not be possible to stop at the floor.

The only way to know what is under the tile is to remove some. I chipped my tile off as well as the mortar bed under it. I then capped the hearth with a soapstone slab.

 

[elmoleaf]

Mine was almost identical. Built in 1965. Perimeter was 3 courses of brick topped with slate. Interior was filled with sand. The concrete cantilevered hearth extension surface had been held flush to surface of subfloor, which is 3/4" below top of adjacent hardwood floor. As pointed out, floor of firebox is separate from hearth extension.
I had to clean up a bit where previously hidden brick was now left exposed by removal of elevated portion. Incidentally the plywood form below the extension should be removed.

 

[jillybeansisme]

A buddy of mine has a raised hearth -- his is filled with brick ONLY because one of the guys working on it wouldn't let the other guy go collect junk rock from the desert.