The essentials are that the bees either don't have access to the sticky board (under a SBB) or it has some kind of matrix for the bees to walk on without getting stuck. When you buy one it usually comes with some kind of plastic mesh for the bees to walk on. Contact paper works fine under the SBB. Contact paper works fine on a regular bottom board if you put some #4, #5, #6, #7 or #8 hardware cloth on it.