My office room has a deck above, 12'x12', and is leaking on the side. The deck is finished with terra cotta tiles, plastic and other impermeable layers, but it leaks anyway. I'm going to have to rip up the deck and replace, plus redo the ceiling and walls inside to get rid of what ever is rotten. I haven't had to do this kind of repair before and am really nervous. I don't want to fix the thing and have it leak again, but I would expect it. I also don't want to keep throwing money at the problem. ?@#! I don't think a tarp or a sail will suffice for long. I'm thinking many thousands of $$$, but have no idea how many. I wish it would stop raining already.