How To Install Metal Roofing Over Existing Shingles. The metal roof must rely on the building’s framework for full support. This will provide ventilation while protecting your new roof from the abrasive shingles.
To tear off the shingles and replace with a new roof or to install a metal roofing system over the existing roof. But not all metal roofing can be installed on battens, so you will need to check the roofing you choose to make sure it can be used this way. This is more expensive but will also be higher quality.
Most buildings are designed to support the heaviest roofing systems.
This is what it looks like when you install a steel shingle roof system over an existing asphalt shingle roof. The first is running new underlayment over an existing shingle roof, thus covering the old roof. It will also give you a nice, flat surface to install your panels on. This will help prevent water leakage and provide a buffer between the metal roof and the existing shingles.