3 Million Dollar House in Avila Beach With Failed Tile Deck "Waterproofing"

Great View From Avila Beach roof deck

Rotted subfloor, metal lath visible in closeup view

WTF? No, you don't run irrigation lines under tile decks!

Heaved up tile in center of deck

Here's another shining example of a tile deck  over a waterproofing system done badly, this time on a 3 million dollar home in Avila Beach.

There's 1500+ square feet on the main level deck and roof deck. The decks were waterproofed with a metal lath, concrete and urethane with sand broadcast into it (sand gives thinset something to grab when installing the tiles). The manufacturer is unknown but several make a tile waterproofing system similar to the system here.

So what's wrong you ask? It would be easier to answer with what's right...NOTHING!
The tile & grout have cracks all over, indicating excessive movement in the sub-structure. The tile is heaved in several places, indicating moisture underneath. The tile is higher than the door thresholds, trapping water in the thresholds, allowing water out under the tile vis a vis the weep holes doors have built in them...

The deck/tile has no allowances for expansion/contraction that occurs in exterior conditions. No mortar bed to provide a firm base. The substrate it's built over is only 3/4" plywood, not the minimum 1" as recommended by TCNA. The joists are woefully undersized, at 16" on center and only 2" x 8", can't possibly provide the necessary stiffness a tile deck requires.

This deck is a total tear off and redo, sans tile. The deck is obviously not designed for tile, but some idiot went ahead anyway...

Estimated costs to repair and redo with a traffic coating-$70,000-$80,000...
and tile is not an option!


Central Coast Waterproofing, the deck experts, is a authorized installer of Mer-Kote tile deck waterproofing systems. For your next tile deck project, call the experts at 805-545-8300 or pay the price of failure!