The frame of premium 20.5″ octagon is made with side walls of 1/8″ thick aluminum 1″ high. The corners of the frame are welded. Two layers of tiles made from pressed basalt fibers insulate and dissipate the heat. Basalt is a fire-proof volcanic rock. The basalt tiles are almost flush with the top of the side walls. Hard rubber feet raise the frame 3/4″ for air flow and to assure that your deck or patio will not become stained from trapped moisture.
The dimensions shown here are inside the aluminum frame. It is best to place the feet of your fire pit within the side walls sitting on the basalt tiles. The inside dimension of the 20.5″ octagon is 20″ flat side to opposite flat side. Assuming your fire pit has four feet, they should be no more than 15″ apart outstide of one foot to the outside of the next foot. For best protection, the diameter of your fire pit should not be much greater than the width of the DeckProtect.