1. Metal Roofs Are Not Just In Architectural Digest Anymore
Metal roofs used to be found only on architect-designed houses. No longer a novelty, metal roofing is increasingly found on more conventional houses.
2. Metal Roofing Can Be Installed Over Your Existing Roof
Metal roofs can be installed over your existing roof without tearing off shingles. While shingle removal is the preferred route, it is also messy and raises the cost of the job.
Water vapor in conjunction with a metal roof on existing shingles is a problem. Water vapor build-up and attendant mold and rot are not reasons alone to avoid installing metal over shingles. Roofers can install a vented metal roof can be installed over existing shingles which would eliminate the vapor problem.
Also, installing the metal roof on top of furring strips (1×3’s or similar) will raise the metal and provide an air pocket between it and the shingles.
3. They Are No Noisier Than Asphalt Roofing
Surprisingly, properly installed metal roofing is no noisier than any other type of roof. Metal roofing is typically installed over a solid substrate. Additionally, the attic and insulation provide a sound barrier. If you wish to install metal roofing over your existing roof, the metal roof will most likely be raised over the existing roof by means of furring strips. These furring strips will create an air pocket which will further deaden sound.
4. Metal Roofing Does Not Attract Lightning More Than a Conventional Roofs
Yes, it does seem like metal roofing would attract lighting, but this is faulty logic.