oven floor

[NickR.]

can two layers of firebrick be used for the floor also do you cement the firebrick to the floor

[Chach]

That is a lot of thermal mass and will take a lot of fuel to get the oven up to temperature INMO the bricks do not get cemented down but a 50/50 mixture of sand and fire clay is troweled with a notch trowel and set like tile which allows the floor to expand and contract without cracking.