I have never liked flat roofs. It just does not make sense to me that a roof that has to take snow and water should be flat. The snow builds up, and the rain does not run off like it does on a pitched roof surface. Our garage at home has a flat roof, and I have been up there days after a rain to see puddles of water still lingering if it was cool out. Hot days evaporate it fast. I called a place that does flat roof repair in Brooklyn NY to come out after my last inspection of our garage roof. I saw that the rubber membrane that covers the roof surface was dry rotting in spots. It was so brittle that it crumbled when I touched it. I was surprised we did not have any leaks yet in the garage.
The garage we have is actually a four-bay block building with big garage doors for each bay. The previous homeowner was a car buff, and had it built for his hobby. They moved out west to participate in the car scene in a place where the snow does not fly. We removed all the garage doors and closed up the space with framed walls. For one bay we put in a smaller garage door big enough to get our two vehicles in one big bay. The rest of the space was closed off and separate, and we used it as a studio to do our art in. Now it needed a new flat roof. When the company that does flat roof repair in Brooklyn NY came out to redo the roof I was up there looking at what was underneath the rubber membrane. There were all kinds of spots that had been absorbing small amounts of water. They were stained and weak and mold was growing. Our new white membrane roof reflects a lot of heat, and it makes the space much easier to cool in the summer now.