What is the best metal roofing material?
Short answer. For most Georgia homes the best metal roofing material is Galvalume steel, steel coated with an aluminum and zinc alloy, because it resists corrosion well at a reasonable price. Aluminum is better near salt water, while copper and zinc last the longest and develop a natural patina but cost far more.
The metals compared
- Galvalume steel: the standard for residential standing seam inland. Strong, corrosion resistant, widely available in painted finishes. Cut edges and scratches are protected reasonably well by the coating.
- Galvanized steel: zinc coated steel. Durable and economical, but in general the coating wears faster than Galvalume in many environments.
- Aluminum: does not red rust and handles salt air, which is why coastal homes use it. Softer, so it dents more easily in hail, and it costs more than steel.
- Copper: can last generations and weathers to a brown then green patina. Very expensive, mostly used for accents, bay windows and historic homes.
- Zinc: long lived and self healing as its patina forms. High cost and specialized installers.
Mixing metals is a mistake
Different metals touching in the presence of water can corrode one another. Avoid copper flashing or copper runoff on Galvalume or aluminum, and use fasteners matched to the panel metal. Galvalume also should not be in contact with wet concrete, mortar or certain treated lumber.
Finish matters as much as the metal
Most residential steel is painted. A PVDF finish holds color and resists chalking far longer than cheaper polyester finishes, which matters under Georgia sun.
Which one for North Georgia
Inland from the coast, painted Galvalume in 24 or 26 gauge covers most needs. Choose aluminum only if you are near salt air, and copper for accents rather than a whole roof unless budget is no issue. See metal roofing in Georgia and roof flashing explained.