My house is 60 years old, and my wife and I want to paint it. It has asbestos shingles on the exterior that have never been painted before. We also have aluminum widow casings, and gutters. There is some discoloration where the water runs off the roof on both the shingles and the aluminum. We live in FLorida and our house has has very little shade. What steps do we take to properly prepare to paint. Any help is greatly appreciated.