Question: i am in the process of designing a hearth for my wood stove. this stove is in my living room and i want to make it the focal point of the room and build a high quality project to code. code requires a air space for the wall, using cement board. i want to use tile on the cement board but i cannot come up with a idea of how to cap the top and sides of the cement board for a clean high quality look and keep the air gap effective. any ideas? thank you Answer: In most, it is OK to have the air space at the bottom and top only. The cooling air rises behind the board, so this is usually very effective. If you run the tile up high enough, the top will not be visible. The other option would be to use a grill that you could make from the chrome or brass "radiator cover" material that is available at many hardware stores.