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
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 (1x3'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.
According to a technical bulletin from the Metal Construction Association, "Metal roofing does not in any way increase [the risk of a lightning strike."
As the bulletin asserts:
Because metal roofing is both an electrical conductor and a noncombustible material, the risks associated with its use and behavior during a lightning even make it the most desirable construction available.
5. Their Warranted Lives Are Equal To Conventional Roofing Products
If you live in fire-prone areas, such as Southern California, metal roofing will extinguish any embers. Insects such as termites can never eat metal roofing. Metal roofing is impervious to rot and mildew.
Because it conducts heat quickly from the sun, snow slides off more quickly than with conventional roofing.
Even so, most metal roofing manufacturers will warrant their products only for an average of 30 years, which is about the same as conventional roofing manufacturers.
6. Metal and Low-Pitched Roofs Are Like Peas In a Pod
Because metal roofing comes in larger sheets and the pieces are so tightly sealed together, you can install metal roofing on gently pitched roofs.
7. In Severe Hailstorms, They May Be Irreparably Damaged
Metal roofing will weather pea-sized hailstorms. But if your area ever experiences severe hailstorms with larger stones, your aluminum or copper roof may get dented. Steel is harder and will fare better in the event of a hailstorm.
8. Modifying Metal Roofing Is Next-To-Impossible For Homeowners
Asphalt shingles are easy to replace because they are available at your local home improvement store and because you are working with small pieces.
Metal roofing, on the other hand, is generally available only through select retailers. Also, the large sheets are difficult to handle and fabricate unless you are a professional.
9. Ridge Venting Will Be More Obvious
On a shingled roof, the continuous ridge vent (CRV) is the strip of shingle-like material that runs the entire length of the peak of the house, masking outflow holes.
On composite roofs, you have seen this countless times but probably never noticed. One reason is because the CRV lies very flat. Also, the two materials blend in with each other so well.
On your metal roof, the CRV will be metal and will stand out a bit farther and be more obvious. However, these thick, prominent lines or ridges are inherent in metal roofs and add to their distinctive look.