Hi. Approximately 9 years ago, I replaced the roof on my house. The house is I think 1959. The roofer at the time suggested we use a rubber roof made from recycled tires for a portion of the roof that is flat. Here the problem is though, over time the roof has become convex just enough to hold water in it after a rain. The water than stands there and only has usual evaporation. The water then starts seeping through the rubber, to the interior painted textured ceiling. The "phantom moisture" becomes steam due to the high temperature in that room, and then pops the texture off of the ceiling. Roofer has gone out of business. Does anyone have any suggestions as to how I make the roof concave so that it does not hold the moisture? Is this something I can do myself? Or should I hire a professional? Any one who has ideas for me I thank you in advance