The tiles have an integrated base with drainage holes and don’t need to be installed on top of joists or bearers. The only requirement for laying Dura Deck Tile Resist is a flat and relatively even surface. Dura Deck Tiles won’t interlock when laid on uneven surfaces, so you must be sure to fix any underlying issues before starting. If your existing patio area is prone to weeds or organic growth, we’d advise laying a weed control fabric down first before laying your tiles.