Green your life at home, work & play

Install a greener roof, even without plants! May 15, 2007

Filed under: Energy efficiency,Green buildings,Green home,Green living — Anca Novacovici, Eco-Coach Inc. @ 10:59 pm

Summer is just around the corner, and with it, increased energy bills from the AC going full-blast. Especially if you’re living in the city, where it can be up to seven degrees warmer due to the heat island effect (read: concrete and other materials that retain heat), this is an issue. One way to decrease your energy consumption and cool your house naturally is through the installation of a ‘green’ roof. However, only do this if you need a new roof! It isn’t too environmentall-friendly to change roofs without reason, and have the remains sit in a landfill!

When most people think of eco-friendly roofs, more think of grass or plants growing on theroof. Those are not the only options, though these should be included in your review of roofing alternatives. As with a regular roof, an environmentally-friendly roof should: protect you from the elements, provide temperature abatement, be fire-safe, and of course, look good!

Below are some of the more eco-friendly roofing options (not insulation), though some are more friendly than others. Consider your climate, dollars you want to spend, its weight and durability, and eco-friendliness in making the decision and note that the costs are approximations and may vary based on your area and the type of roof.

Roof Type
Description Price
Green roof
Vegetated roofs with a membrane and soil, plantings and insulation.
Reduces rainwater runoff and heat island effect. Requires a strong structure.
Fiber-cement composite roofing Made of Portland cement, sand, clay and wood fiber, it is recyclable, durable (up to 50 years) and fire-proof.
$500/square Can be expensive to replace and is not suited for colder climates though it is a good choice for homes in hot and humid climates. It can last up to 60 years.
Metal roofing (lead-free kind)
Usually made from copper, steel or aluminum, it can be made of 100% recycled material, and most can be easily recycled. It is easy to install, lightweight, rigid and long-lasting.
Better than asphalt shingles in terms of decreasing heat radiation, especially if use a white painted or galvanized finish on the metal to deflect heat.Cost quotes is for corrugated steel roofing; others may cost more. Relatively inexpensive but may require metal coatings, factory-finished panels, or watertight construction detailing.
Clay tile
Durable and weighty.
$300-$600/ square Great for warm climates but doesn’t do well in cold climates, and it’s tougher to install solar panels on it (if that is a consideration).
Recycled synthetic shingles Durable recycled rubber and plastic shingles (again, 40-50 years) and sturdy.
Works in colder climates and earthquake areas. Some insurance companies offer discounts if installing these.
White EPDM rubber During and after installation, it doesn’t release odors and fumes, as some other types of roofing materials do $120-$160/
EPDM stands for ethylene propylene diene monomer and is a single-ply roofing membrane. Commonly used for low-sloping roofs, and simple to install, it also has relatively low maintenance costs. White is recommended because it has a higher reflectance (69% vs. 6% for black).
Cast-concrete tiles Fire-resistant and look similar to fiber cement roofing. Some contain recycled material and generally last a long time, require low maintenance, and are fire-safe. In addition, they have great insulating properties. $250 to $300/square May need stronger structure. Also, freeze-thaw cycles can damage the tiles unless treated for it.
Slate Long-lasting (up to 100 years!), fire-resistant, and can be reclaimed and reused.
$900 – $1200/ square
Comes from the mid-Atlantic and Northeastern states and Europe, so tranportation costs may make it more expensive, depending on where you live. Requires minor maintenance.
Building-integrated photovoltaics (BIPV) coated with a film that converts sunlight into electricity. The shingles or tiles snap together, and the electrical current flows at the edge of the roof. The shingles look like slate or can be applied to standing-seam steel. $7,000+/kW or square
In terms of solar energy options, this is an expensive options (a square of BIPV generates only about 1 kW of electricity).
Recycled-content asphalt shingles Made up of recycled, mixed paper; some use reclaimed minerals in the surface aggregate. Can last up to 50 years. $150+/
Asphalt shingles are generally not eco-friendly — they are made from oil products, off-gas chemicals into the air when hot, and are tough to recycle; however, because these are made of recycled content, and last 50+ years, they have been included here. That being said, avoid products containing built-in moss inhibitors as many contain zinc, copper and other toxins that harm aquatic life.

* A square = 100 square feet


2 Responses to “Install a greener roof, even without plants!”

  1. We don’t think it’s as easy as your everyday peel-and-stick adhesive bumper sticker, but just the same. It sounds like a major improvement from the tedious drilling and constructing that goes into the installation of ordinary solar panels. The Lumeta PowerPly solar panels are glued in place on the roof, using adhesives normally used in roofing. So far the method/product is only available for commercial buildings, but we hope an application for private homes will be in the market soon.

  2. Jeff Levengood Says:

    you are mistaken in your comments re: asphalt shingles- they ARE recyclable and large volumes are being recycled in some regions. However this is not widely available as this time.

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