Roman

I already thought about that idea, but since the deck is fairly large and the irregular shaped, it may not be that cheap. It is also fairly windy at times. I would like to find out what options I have in terms of properly water proofing the deck in the interim and once I remove the tiles.

nealtw

The cracked tile would suggest,plywood to thin, joist to small or overspanned. the waterproof membrane should run up the walls some inches. Like Old Dog I can not see where the water is draining . What is the slope of the deck?
I too think it might be better to look at a light weight roof.

joecaption

You have posted all over the net and everyone agrees this is never going to work out. T111 is not supposed to be installed within 6" of a solid surface or grade. What you have is just going to keep rotting out. All that walls done is form a dam to keep water from running off of the deck.
Unless there solid concrete under that tile it's never going to stay in place or stay sealed. Under that tile by now is rotted wood and rotted ceiling rafters.