I am building a multi-level deck in my yard. The landscape is hilly which makes it is easier to wood frame different levels of decking to eliminate several retention walls. I want to use a thin (approx 1/4" - 1/2") slate/tile as the surface of a wood framed deck. My question is, can I use a 3/4" pressure treated plywood base, then 5/16inch concrete board, then apply Slate/tile? I will frame the deck to support the weight of the ply/concrete board & tile.