Installing tile over a standard deck frame in an exterior environment is a recipe for trouble. The combination of tile, grout, wood and water in an environment with temperature and moisture fluctuations makes it nearly impossible to get the long-term performance that most occupants expect. For a deck that is partially enclosed under a roof and protected from heavy precipitation, a conventional tile floor could probably be achieved, but otherwise, proprietary systems designed for deck applications should be considered.
There are a few products on the market that allow for a finished tile look on an elevated wood-framed deck. Some systems involv special tiles designed to install without grout in a grid system. These systems allow for movement and drainage. There are also systems designed for dry-laid pavers to be installed on decks, providing a similar look to a tile floor. New products are consistently being developed and brought to market, so it’s worth exploring if a tile deck is the look you are interested in. In evaluating such a product, keep in mind the environment it will be installed in. It will likely need to accommodate differential movement between materials and provide water drainage.