Can metal roofs be installed directly on top of asphalt shingles?
A. In most cases metal roofs can be installed over asphalt shingles, with the proper underlayment installed. This saves you money on labor cost, dump fees, and stripping of your old roof. The only time you shouldn’t install metal roofing directly over shingles is when there are 3 or more layers of shingles or the condition of the structure is unsuitable.