TPO on low pitch roof?
Does anyone have any experience with TPO membrane on a low-pitched roof?
We recently had this type of roofing installed on two roofs (one over the garage and one over a sunroom addition) and although the material appears to be performing (no leaks), we are having problems with the "look" since the roofs are very visible from the upper level of our house. The material is "welded" down around the edges, but "floats" in the middle and when the sun heats up the roof, the material expands and makes ripples... kind of like a poorly-made bed. The next morning it is flat again, but then the sun heats it up and we get ripples again... over and over. The roofer says that this is "normal" and it will "settle down" after the winter, but I'm not convinced.
Any thoughts or experience?