How To Install Metal Roofing Over Existing Shingles. It’s important to first inspect the plywood under the asphalt shingles to make sure it is in good condition. The low weight of metal roofing is one thing that encourages this.
This allows the new underlayment to act as a line of defense in the event that water somehow gets under the metal roof. The metal roof must rely on the building’s framework for full support. Roof slope is 3:12 and there is no attic.
The purlins give the installer a flat surface to install the metal roofing.
Methods of installing metal roofing on top of traditional shingle roof. To tear off the shingles and replace with a new roof or to install a metal roofing system over the existing roof. Methods of installing metal roofing on top of traditional shingle roof. Roof slope is 3:12 and there is no attic.