Question: I just bought a fireplace(woodburner), and would like to know what I can use as an inexpensive base underneath since I am on a limited budget. I have access to some flagstone-- will it work? Answer: I don't know exactly what stove you have, so the floor specs given below may not apply, but here are some ideas: 1. Lowest possible cost: 6 inch or 8 inch cinderblock set on their side so air tunnels are horizontal, set on top of a piece of sheet metal - This does a very good job of stopping downward radiation, but does not look all that great. 2. Use two sheets of durarock or wonderboard cement underlayment, nailed or screwed to the floor on top of a thin piece of sheet metal....set tile or flagstone on top of this. These examples should be OK with most stove that have legs of at least 5" underneath them.