The roof at the front of the trailer is leaking at 3 or more of the seams. The front seam is where the fiber glass and steel meet. I've tried a sealant from an RV repair shop and also the as seen on tv flex seal. Neither worked well, if at all. I live in the mountains of Colorado so there are wide temperature fluctuations. I want to insulate and put up walls inside the dressing area, but can't even leave a mattress inside because the roof leaks. I keep it covered with a tarp when not in use. What is the best material to seal and waterproof this roof that will last for a long time? What kind of prep needs to be done? Thank you.