Most environmental considerations with residential roofs are common to roofing in general (discussed in the previous section). Examples of common residential roofing materials that offer some environmentally preferable features include:

• Clay and cement tiles, which are very durable and made from abundant materials, but also heavy and expensive
• Recycled plastic or rubber (sometimes mixed with wood) shingles, which are durable, can be lightweight, are sometimes recyclable, but are not biodegradable.
• Fiber cement is durable, fire- and insect-proof, but heavy and not renewable or biodegradable. At the end of its life, it can be ground up and used as inert fill, but not otherwise recycled.
• Metal roofing is durable, fire- and insect-proof, contains significant recycled-content because steel and aluminium are heavily recycled, and is recyclable if not coated with vinyl. However, mining and smelting are energy intensive and cause significant pollution and habitat destruction.
• Built-up roofing is used on nearly-flat residential roofs. Its durability is strongly dependent on the structure, installation, flashing, and membrane chosen. Most membranes are not made from renewable resources, but some products contain significant recycled content. High-VOC products emit air pollution during installation.
• Vegetated green roofs can be designed for any slope up to 90° (vertical), but are most commonly applied on slopes less than 30°.
• Wood shakes are biodegradable, but not very durable and flammable. Losing a home to fire is costly in terms of money, pollution, risk to neighbors and occupants, and natural resources. For this reason, even FSC certified wood shakes are not a “green” option for fire-prone areas.

See the green materials kiosks on display at the Santa Cruz County, City of Santa Cruz, and Scotts Valley planning and permitting counters for samples and more details regarding extended-life asphalt composition, recycled plastic, and metal roofing.

Green materials databases that can connect you to environmentally preferable roofing: