3 months ago we had a wood deck 3 to 4 feet above ground approx 400 square feet. Then the contractor did the following things to prepare the wood deck for tile (sorry, I do not know the product names for this process):
1. Placed dura rock on wooden deck
2. Laid organge water proof layering (New item they told me) over dura rock. It had a waffle finish and pattern with squares approx 1/2 inch.
3. Sealed the seams of orange stuff with sealer of some type.
4. Used leveling agent to create a slope on the deck to increase water run off.
5. Laid tile with expansion joints every 10 feet or so in both directions
6. Grouted using a flexible type grout.

Immediately noticed white bubbles coming through grout in what looks like a small pinhole. However, the pinholes were not in the grout prior. It looks like a small volcano coming out of grout, especially when temperatures increases. The white bubbles smell like vinegar, or something like vinegar - acidic.
The tile people are coming back to inspect and see what is going on. Help! What is this stuff? I have a bad gut feeling something is really wrong and I am afraid that they will try to get out of this and say that is is typical, etc. The total cost of tile project was approx. $10,000.00

Sounds like he used the Schluter Kerdi membrane but it would help if you could tell us more about the grout and adhesive used. The type of deck you describ does not usually get a tiled surface. Where do you live and what was the deck made from?