Metal: Durable and attractive, metal roofs, such as steel or aluminum, unfortunately have a high energy cost to produce. However, on the positive side, they can be easily recycled, and typically contain a high recycled content. Choices include steel and light-weight aluminum.
Clay tile: Like slate, clay tiles, or terra cotta, clay tiles are both durable and expensive. Again, like slate minimize environmental impact by minimizing transport cost, or checking for salvaged clay tiles in your area.
Wood shakes: Cedar is the most common composite of this potentially very sustainable option. Shakes produced locally and without chemical additives or preservatives are an especially sustainable choice.Asphalt shingles:
As mentioned above, both the most popular and least sustainable, asphalt shingles also do not rate high in durability, and due to their dark color, can lead to heat gain. On a positive note, asphalt shingles can be produced with some recycled material, depending on the manufacturer.
Concrete tiles: Hard on the environment to produce, concrete tiles are quite durable. Due to their weight, they may not be appropriate for every roof. In terms of their environmental impact, the transportation of this roofing material, as well as the inability to recycle them, are the two prominent factors that make them less than sustainable.Fiber cement:
A mixture of cement and cellulose fiber, fiber cement is obviously much lighter than cement, but also can be made with recycled fiber material, making them more sustainable than traditional concrete tiles. Additionally, their lighter weight reduces the environmental transportation impact. Lastly, fiber cement is both weather- and fire-resistant.
Recycled roofing materials: An attractive option due to their durability, plastic and rubber can be recycled and formed to emulate wood shakes or slate. This option, however, is not as widely available as many others, so transporting to your local area may be a concern.