QUESTION

Can I adhere Ceramic Tiles to a Waterproof Membrane on an Exterior Deck? - Is it possible to adhere ceramic tiles to a waterproofing membrane over a concrete roof structure, over interior space in a climate such as Seattle?

ANSWER

ANSWER - Ceramic tile can be adhered directly to certain types of waterproof membranes, which are designed for ceramic tile or stone.

A roof that has a concrete substrate, over interior occupied space, can have ceramic tile or stone installed on top of it. First, the ceramic tile or stone needs to be frost proof (less than 3% absorption) for freeze thaw climatic conditions. The concrete substrate needs to have a deflection of less than L/360 for tile and L/720 for stone, and the substrate must be sloped to a drain within the deck areas or sloped to the roof edge to drain into a rain gutter. A primary waterproof membrane needs to be applied on the concrete substrate and if necessary a mortar bed is installed on top of that. Then you can adhere the tile.

Good Luck!