I want to frame out a 16" raised hearth for my new wood stove. Stove will go in the corner and I thought I would build the frame out of 2x6 lumber and 3/4 plywood sheathing. I will then cover with cement wonder board and finish the hearth with a tile or brick veneer. Should I worry about the lumber under the cement board getting to hot? I planned to place a couple of vents in the hearth for air circulation. What do you think?