The most common materials used for metal roofs are steel and aluminum.

Aluminum sheet roofing that is anodized or painted is highly resistant to corrosion, making it well-suited to coastal environments provided it is factory-coated with a suitable finish.

Aluminum roofing, softer than steel or copper, dents easily and so may suffer cosmetic damage from hail. Hail damage is reduced if the aluminum panels are well secured to solid roof decking.

Aluminum roofing's light weight is an advantage in reroofing. Aluminum roofing also reflects heat and may thus reduce building cooling costs in hot sunny climates.

Because of its high coefficient of expansion, however, attachment systems must be designed to accommodate the movement of long aluminum roof panels.

And since it has a lower tensile strength than steel, more fasteners may be required to achieve wind ratings comparable to a steel roof.

Most aluminum used in roofing has a baked-on paint finish rather than an anodized finish.

Choose the right metal roof for your home. This expert overview discusses and compares steel, aluminum, copper, and other metal roofing materials.

Steel, used for most metal roofing, is heavier and sturdier than aluminum. Manufacturers have settled on a number of durable coatings and finishes that protect steel from rust and corrosion. Steel is usually zinc-coated for corrosion protection and then sealed. A coating of epoxy primer offers adhesion and a baked-on acrylic top coating adds color and protection. Because sheet systems are designed for commercial applications, they generally are given highly durable paint finishes. One popular fluorocarbon coating used on many products is called Kynar.

Copper metal roofing, rooted in centuries of use, will not rust, has no “finish” to scratch or peel, is soft enough to easily tool, and weathers naturally to a beautiful verdigris patina. Unfortunately, it’s extremely expensive.

Alloy roofing products are formulated for strength, graceful weathering, and durability. Cost depends on the specific material, but, as a group, they are pricey.

Stainless-steel roofing, a very expensive roofing material, won’t rust or corrode. The coating can give it a natural matte-gray finish.