I have owned two Sunlines: an older 23' trailer and now an older 27' trailer. The 23' trailer had an aluminum skin roof surface that was seamed in two places. The 27' had a single ply rubber roof. Both of these trailers had small holes develop. The metal roof was punctured by a falling branch while in storage. The single ply roof developed a dime size hole - which almost looked like a manufacturing flaw with a factory repair that finally failed. I handled both the same way - with a product called Snow Seal. The first step is CLEAN THE ROOF. This product's instructions were very good, and there were illistrations and a video on the web. Get a good long brush, some cleaner (I found I did not need a special RV cleaner for this...) and get to it. I think I just used a $3 box of TSP and some soap in water. Pay attention to the edges too. The Snow Seal product was a bit expensive. I bought a 5 gallon pail, but I think I could have gotten away with 3 single gallons. The Camping World store in Belleville, MI where I purchase the product both times also sold a patch kit. I needed that for the tear in the metal roof, not for the dime-size hole in my second trailer. Get yourself a good pair of sunglasses and wait for a couple very sunny days. This stuff cures in sunlight more than it dries in place. Get some blue masking tape too for the edges. You basically just roll this product on over the surface. You put on multiple coats. I found and old Teflon pan and coated it at the same time, so I could peel it off the pan and examine its characteristics later. After 4 coats it made a white skin that reflected lots of light, and would stretch at least three times its original size. I froze it and it still remained flexible. there is a silver product out there, but I thought it would likely absorb a lot more sunshine than deflect it, and I'd rather have a cool trailer in summer. I chose the while color over silver. Hope this helps. If you can paint a wall in your house you can do this to your trailer. Good luck!