Installing a Bluestone Hearth

I have a blue stone mantle and a flush field stone hearth so take this for what its worth.

Both are held in place with mortar.
The mantle for obvious reasons, its about 6 feet long, 5" thick and 10" deep. 4 of us picked it up and placed it while the mason shimmed level with chinks and tooled the mortar.

The hearth in your case will need to be adjusted level front to back and side to side in order to have the proper exposure from the finish floor to the top of the hearth. Unless you spend extra to have the back side of the blue stone honed so that the bottom surface is completely parallel it likely you will need to have the mortar bed to adjust it. Think of thin set and a tile floor.

I'd remove the tile wanting the hearth to be a flush as possible. A raised hearth is great if you have huge space but not being forced to walk around it is nice feature. We walk over ours all the time.

AndyMac said:

Thanks for the reply!

I actually would prefer a raised look to the hearth. I plan to building shelves on either side of the fire place so walking over the hearth won't be possible either way.

What if I mortar a cement board to the exiting tile and level that, and then just place the stone on top of the cement board?

Click to expand...

You want the finished elevation, in this case the top surface of the blue stone to be level. It is most likely the only piece that might be out of parallel. Of course if your raising the hearth anyway then it doesn't much matter. The more it's elevated the less anyone will notice within reason of course.

I would remove the tile and put down some tar paper then either cement board or metal lath. Cut it a 1/2 inch smaller then your stone on the 3 exposed sides. This will give you room to grout your edges. Add a little mason sand when you grout. This will give a nice look when you sponge the stone down. Even if you get a thermal treated piece of stone it can still have a little twist or bow to it. So just setting a piece of bluestone on your existing tile might not work the way you are wanting it to.