The green revolution has touched many industries, and residential remodeling is clearly one of them. According to the U.S. Department of Energy, green-improved buildings could potentially save $20 billion a year in energy costs. Homeowners are paying attention, both to reduce the strain on natural resources and to save up to 50% on energy consumption using sustainable building techniques.

When it comes to green renovation, however, the roof isn't usually first on the list. The U.S. Department of Energy attests that roofs are generally much less durable and energy efficient than other parts of building structures. Being that it's the home's last defense against the elements, upgrading it should be a priority. Working in conjunction with a well-insulated attic, environmentally friendly roofing can go a long way to keep the home's heating and cooling system functioning optimally. If it's about that time to renovate your roof, you've got a big and important project on your hands. That said, here are some things to look out for when planning for a green roof.

Is the material energy efficient?

Energy-efficient roofing can excel either in reflective quality or heat absorption. The attribute you select depends on the climate in your region. For instance, Low Impact Living says urban locations typically prefer a "cool roof" with light colors. Cool roofs are also recommended in hotter, more humid climates.

Examples of cool roofs include metal and clay. Clay comes in a wide array of light color possibilities that deflect up to 50% of the sun's solar energy. At the same time, it is a great insulator, keeping the elements from significantly impacting indoor temperatures. Metal roofs made from copper, aluminum, or stainless steel are also known for staying cool in temperature. They come in multiple colors, such as silver, red, green, blue, and brown, in addition to a darker black. Metal is surprisingly versatile, imitating Spanish tile and traditional shingles.

Insulative ability is another good indicator of energy efficiency. Asphalt isn't known as a good insulator, with wood being twice as insulative. Metal roofs have high insulative value, as do those made from clay tile.

When searching for an energy-efficient roof, you can't go wrong searching for Energy Star-rated reflective roofing products. 

Is the material sustainably made and disposed of?

Roofing is currently the second largest contributor to solid waste generation in the United States. Recycled products help deflect these amounts, putting used resources back to good use. Take metal roofs, for example. Virgin metal poses a drawback because it requires a lot of energy to manufacture. However, metal can be purchased in a recycled variety, cutting back on production costs and environmental stressors. Once it has lived its purposed, metal is completely recyclable, avoiding the growing landfill.

Other recycled roofing materials include slate, reclaimed clay, and products that contain everything from recycled rubber to recycled plastic. Panelshake, for instance, is made from post-consumer milk jugs, waste wood fibers, and waste jute.  EcoStar offers an eco-friendly alternative to the wood shingle and The Roof Tile and Slate Company offers reclaimed and salvaged slate roofing.

Another way to look at the situation is to avoid roofing materials that clearly don't have the qualities you seek in terms of a sustainable life cycle. Sadly, asphalt is a traditional favorite but doesn't rate well in eco-friendliness. Not only isn't it a good insulator, it's made from petroleum products. Liquid asphalt releases high amounts of chemical pollutants when it's applied. To top this off, asphalt contains fiberglass and can't be recycled.

On the other hand, homeowners who live in colder areas might prefer the dark color of asphalt, which absorbs heat and raises temperatures. In warm climate, though, this will only amount to increased air conditioning costs.

How long will the material last?

Finally, durability is a big factor in the roofing material equation. The longer a roof lasts, the less money and resources will be needed to replace it. Slate is highly durable, but expensive and non-renewable. Metal roofs are also pricey but last two times longer than wood or asphalt. If you want to go for the traditional cedar shake that beautifies with age, you can now purchase FSC-certified shingles. These are sustainably harvested, but like all wood, will crack and decay over time. 

When determining a material's durability, consider not only how long it is estimated to last, but how well it will endure the elements. Cool roofs with light surfaces are easily discolored by fungus and may require fungicide coating. Wood is prone to moisture damage, and may need to be treated with toxic chemicals in order to pass the fire code. Unlike aluminum, copper, and zinc, steel metal roofs are prone to rust and should be coated for corrosion resistance.

There are positives and negatives to every scenario. Remember, getting more of one quality might mean receiving less in another. For instance, you may pay more for metal but get your money's worth through longevity and durability. Slate may last long but requires a lot of energy and renewable resources to produce. Finding a balance is something we all do on an individual basis, depending on our respective locations, energy use, budgets, and priorities. The good news is that the choices are out there for those who are willing to look.

Links:

• Green Roof Materials
• 5 Roofing Types Rated on Eco-Friendliness
• State Energy Alternatives, Walls and Roofs