... of 0.32 for 3/8" board, 0.45 for 1/2", 0.56 for 5/8", and 0.83 for 1" board. In ... inch), typically used for ceilings. 15 mm thick board is commonly available, and other thicknesses are also produced ... board are tapered with a wide bevel at the front to allow for jointing materials to be finished ... flush with the main board face, and plain edge, used where ...