Project #120 | Private Residence Tile Deck, Vancouver, BC

Project: Private Residence Tile Deck, Vancouver, BC


This sundeck was originally waterproofed with Duradek Supreme Granite. Approximately 6 years ago, slate was applied over the Duradek membrane. The contractor installed CPU directly over the Duradek, drilling right through the membrane itself.

Over time, mortar and tile sealants were applied to maintain water tightness. At first this seemed like a successful tile application, however it didn’t take long for the homeowners to realize something wasn’t right.

While on the surface this deck looked great, underneath there were hidden issues. Efflorescence, deposit similar to sea salt had started to show through the tiles and down the sides of the fascia-board.


Insufficient and improper mortar allowed water to soak in an sit in areas where there was no mortar coverage. Exterior tile practices call for 95% coverage as well as a mortar with a low permeability.

Another issue was the improper tile used on the deck. An interior tile will not last long when facing exterior elements day after day. The final and most damaging issue is the waterproofing. While CBU is recommended to stabilize the tile, it should always be installed underneath the membrane, ensuring a watertight, strong structure.

By using Tiledek, the homeowner was given peace of mind and a great looking deck, inside and out.


Even though the original Duradek membrane had been pierced and covered with thinset, it still did its job of protecting the structure from water damage. This being said, proper waterproofing practices are always recommended.

View or download the .pdf version of Case History #120 for complete case history with installer details and before and after images.

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