We are in the process of replacing the tile on our fireplace hearth with a piece of granite. The hearth is level with the fireplace box and the hardwood floor in the living room. I removed the tile and the grout down to the original concrete pad, and I've ordered a piece of granite, but I'm stumped on what to do next. The concrete pad is not level, and the opening in the floor is deeper than the granite slab. I don't know if I need to shim it somehow before I install the granite (with wood? or something fireproof?), or if I need to pour more concrete or add some other substance to make a perfectly level surface to the correct depth.

If anyone has any advice for me, I'd really appreciate it!

Thanks,

Gina