How do I tile to plywood floors?

If levelling isn’t required, prime plywood floors with a single coat of undiluted ARDEX P 51 applied with a brush or broom. Once the ARDEX P 51 is dry, it should then be overlaid with a suitable tile backer board or uncoupling membrane such as ARDEX FLEXBONE VA/2E, which can then be tiled as normal using an appropriate Cement-Based Tile Adhesive. ARDEX AF200 Plus can also be used to bond an uncoupling membrane down as below (no priming required with ARDEX Flexbone 2E or when using ARDEX AF200 Plus)

If levelling is required, level over the plywood with ARDITEX NA applied direct (without priming). It will dry after 3 hours and should then be over sheeted with a suitable mechanically fixed tile backer board, which can then be tiled as normal using an appropriate ARDEX Cement-Based Tile Adhesive.