By far, the number one covering over commercial and residential steep-sloped roofs of the United States is shingles. Developed over a century ago, the more common paper basedasphalt shingle has come far; giving way to a more durable and affordable fiberglass reinforced and recycled rubber shingles. When it is time to replace your roof, you’ll have to decide if you are going to strip the existing roof or go over it with another layer of shingles. We highly recommend stripping the roof, as it allows for full inspection of the deck surface (plywood or planks), transition points, skylights, chimneys or any other areas that may be prone to leaking.