When choosing
flooring and decking materials, I'd recommend that you consider a completely unique alternative to standard decking for your projects, try modular outdoor flooring deck tiles.
If a level surface, moisture, and drainage is ever an issue, this is the answer.
They come in a variety of materials: Ipe (Brazilian Walnut), Granite, Slate, and Ceramic
They typically come in 12" x 12" and do not require a backer board.