The Low Down On Green Living
April 6th, 2008
Eco-Friendly Roofing Materials
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As a passionate green designer, I find few things more boring or environmentally-challenged than standard asphalt shingles on a residential roof. Thankfully there are lots of green roofing materials that have a variety of eco-friendly attributes such as being Energy Star rated or containing recycled content. Oh and by the way, they look great too!
In this piece we’ll focus on roofing material selection rather than on alternative roofing systems such as green (living) roofs or solar PV roofing tiles. You can read more about green roofs in this recent blog posting, and we’ll soon be doing a piece on solar roofing tiles.
When considering a new roof, the two key dimensions you should think about are the material and the color (and, of course, cost!).
First, Materials. A high performance roofing material coupled with a well insulated attic will help to keep your home warm in the winter and cool in the summer. Your roofing material is the final layer of protection from the outdoor elements and from indoor heat loss. When deciding what’s green and what’s not, you should consider several aspects of a given material. These include the raw material source and composition, durability / life cycle, maintenance, and disposal. Often there are tradeoffs: a very durable and efficient material (such as metal) might require more energy to produce. Cost and ease of installation are not necessarily green attributes, but will always be factors in your decision.
Next Color. It should be no surprise that a light colored roof reflects heat and a dark roof absorbs it. Due to overdevelopment in urban areas, an abundance of dark colored roofs (often asphalt) can raise outdoor temperatures. Elevated temperatures impact communities by increasing peak energy demand, air conditioning costs, and air pollution levels. Light colored roofs, often referred to as “Cool Roofs”, are roofing materials that have a high solar reflectance rate and thus help to reduce outdoor temperatures and reduce heat transferred into a house. This happens because cool roofs reflect the sun’s energy and keep the roofing material cooler on those hot summer days. If you live in a heating-dominated climate outside of the city, dark roofs may be the way to go since they will capture more of the sun’s energy during cold weather. But in most urban and cooling-dominated places, light is right!
Color is closely related to solar reflectance, which is measured on a scale from 0 to 1, or 0% to 100%. For roofing materials, the higher the value, the more sun reflected and the cooler the roof. This link to ENERGY STAR makes it very easy to select a cool roof and provides a list of products that pass their standards. Approved products must meet minimum initial and aged solar reflectance values in order to qualify. For those of you that want to take it one step further, visit the US Department of Energy website to calculate the impact of your current roof.
We’ll now cover a variety of roofing materials and discuss why they are green or not.
More than 75% of American roofs have asphalt shingles due to low cost, ease of installation, and resiliency. Unfortunately, asphalt shingles have a low insulative value, a shorter lifespan than many other roofing materials, are made from petroleum products (and release pollutants during application) and are often not recyclable due to the layer of fiberglass between the asphalt minerals. Standard asphalt shingles come in a variety of colors, longevity options, and price points. They are always going to be your cheapest option for your roof, but they have the worst environmental track record. They may make sense in the short run, but over the life of your roof many of the options below are better for the environment and for your savings account.
Wood shingles, such as cedar shakes, are natural, have twice the insulative value of asphalt, and become more beautiful as they age. However, wood is expensive to purchase and install, and it often doesn’t pass fire code unless treated with toxic fire retardent chemicals, which defeats the original intent of using wood. The natural swelling and shrinking of wood can also result in cracks and moisture damage, which will cause decay over time. Historically, many roofing shingles came from old-growth cedar trees, so they were a poor environmental performer. Today, though, you can buy Forest Stewardship Council-certified shingles from companies such as True North Cedar and Koenig Cedar Company.
Metal roofs are some of the coolest roofs around, both in temperature and in looks for homes. Metal roofs are available in copper, aluminum, and stainless steel, and often have a high percentage of recycled content. They have a high insulative value, solar reflectance, and durability, often lasting twice as long as wood or asphalt. They also come in many profiles from standing seam to corrugated. However, metal roofs made from virgin (vs. recycled) metals require huge amounts of energy to transport and manufacture, and metal roofs can be expensive. Some leading manufacturers include Zappone Manufacturing (copper and aluminum shingles from recycled material) and Classic Metal Roofing Systems.
Slate is probably the most durable roofing material, but it can be expensive, with high-end installations ranging between $50 - $100 per square foot. Slate will last a long time, but the fasteners that adhere it to the roof deck will wear out after about 100 years. As a natural material, slate is extremely durable and also recyclable. It comes in a variety of colors and the variation of color is what gives it its unique character. Since slate is extracted from the earth, it is a non-renewable resource, and the embodied energy taking it from quarry to rooftop leaves a large footprint. However, you can find reclaimed / salvaged slate roofing from such companies as The Durable Slate Company and the Roof Tile and Slate Company.
Clay tiles invoke a certain Mediterranean flair, have a lisfespan of 50+ years with good insulative value, and are Class A fire rated. Clay roofing tiles can come in lighter colors which adhere to the cool roof standards and can reflect well over 50% of the sun’s solar energy. Clay roofs are often a little pricier than conventional roofs, but if you like the look and not the price tag, try using them in accent areas like doorway overhangs or only visible areas of the roof. Leading providers of “green” tile products include the previously mentioned Roof Tile and Slate Company, Custom Tile Roofing, and MCA Tile (not reclaimed, but Energy Star / cool roof products).
One last set of options if you like the look of slate or cedar but not the environmental impacts are new recycled roofing materials that look like their natural counterparts. Companies like EcoStar by Carlisle, Re-new Wood and Authentic Roof have products that contain recycled rubber and plastics, are half the weight of real slate, and have a 50 year warranty. They also have a variety of colors and profiles that look like the real thing.
There are MANY other roofing options out there, so speak with a green builder, preferably one that is familiar with the energy star standards like those found here, for more information on alternative roofing and cool roofs. Don’t be an asphalt– put on a cool roof today!
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Comments
Nichoel Farris, Owner & Designer of Eco Manufactured Homes
April 6th, 2008 at 1:44 pm
Chosing a metal roof with a cool coat has a higher SRI and lowers the temperature. I am currently designing a prefab green manufactured home for the Auburn CA Home Show, which will have a metal roof. This also allows us to implement a rainwater catchment system. The water quality is higher from a metal roof than an ashpalt roof. I also suggest installing a reflector under the roofing material.
Rob KM
April 8th, 2008 at 7:56 am
If you really want to go ‘green’ you should consider an actual green roof. Green roofs are more common in Europe, but are more and more used on big office buildings in cities throughout the US. However, the huge benefits of green (planted) roofs on residential structures outweigh the initial costs. They are great insulators, reduce water runoff, last up to three times longer than conventional roofs, and look great! I installed a small extensive green roof, which is doing wonderful, on my shed, and I have plans to install green roofs on my sunroom, mudroom and 24×20 garage. Depending on where you live, you can use a wide variety of plants. I live in Brunswick, MD, and use sedums, cacti, and herbs. A green roof takes more planning and prep work, but is definitely worth the time and money investment.
Caroline Nolan
April 8th, 2008 at 8:06 am
In the latest issue of our new magazine, the Living Architecture Monitor published by Green Roofs for Healthy Cities (www.greenroofs.org/magazine) we feature research that from three Ph.D’s in Michigan who set out to quantify the value of a green roof investment using a Net Present Value approach that incorporates the big three public benefits of green roofs: Energy savings (from reduced heat island effect etc.); stormwater management and cleaner air. Their research concludes that when these public benefits are included in a NPV, a green roof on a one-storey green roof in Michigan is between 23 and 40 per cent less than a convention roof on a 40-year, with a breakeven point for the green roof investment of between 12 and 18 years. (A conventional roof requires replacement between 18 and 22 years.)
Glenn Silloway
April 8th, 2008 at 8:57 am
thanks for the newsletter and info in post. I am looking for a new roofing system, and your post is a little depressing. I have looked at all the links you offer for roofing systems, and without exception they are high end. The price gap between standard asphalt and these systems is large, both for materials and installation. Surely there must be some options somewhere in between? If not, it is either a big opportunity for someone, or an unwelcome indication of the reason green alternatives are so rarely chosen: cost. Can someone offer some options (if it matters, I’m on the CA Central Coast)?
don martin
April 8th, 2008 at 2:03 pm
I agree that there are more environmentally friendly roofing options than asphalt shingles but the choice of roofing material should have negligible impact on the energy consumptiuon of a properly insulated building. Use insulation to reduce heating and cooling loads - not roofing materials. Green roofs are great and make sense in a high density urban areas where heat island effects and impervious surfaces are significant problems but when your budget is limited and choices have to be made, always prioritize spending your money on reducing operational energy needs and on water conservation.
If your budget doesn’t allow for metal, slate, or any of the longer lived roofing options, make sure your asphalt shingles utilize by-products (coal slag, trap rock fines, etc.) that would otherwise be landfilled and be aware that in our area it is possible to recylcle asphalt shingles.
Jason Pelletier, Low Impact Living
April 8th, 2008 at 11:18 pm
Don et al:
Thanks for your comments on this posting. We definitely feel your pain on the cost of some of the options we presented. As with many greener products, some of the more expensive options are actually cheaper over the long term (say 10+ years), but the up-front cost is a bit to bite off. Solar panels are another example - good economics long-term, but a pretty significant up-front investment.
So, we’ll do some more research and try to find some green options in addition to the ones Don pointed out that have lower up-front costs, and will update our post as we find them.
Green Wednesday: 5 Roofing Types Rated on Eco-Friendliness » Remodeling Blog
April 30th, 2008 at 4:32 pm
[...] roofs with solar panels or actual plantlife growing from them. Low Impact Living recently published a great piece on roofing types, and much of the info is highlighted below. Remember, the roofing types mentioned [...]
Krystal
July 5th, 2008 at 9:54 am
I keep finding all these great eco-friendly options in theory but I can’t utilize them. I need something that is or looks like asphalt shingles. I live in a townhouse community and I’m required to maintain uniformity and match my neighbors. What options do I have if I must replace my damaged roof?
Shayna Prunier
July 7th, 2008 at 1:22 pm
A product that I have seen that might be an option to have a similar look to asphalt shingles is a product called Metro Roofing. Metro is actually a metal panel roofing system that is coated in ground stones Here is the link to the green attributes of the product, they do qualify as a cool roof from Energy Star in some colors, they may have recycled metal in the panels, and they are also recyclable. They have a product that looks exactly like asphalt shingles called MetroShingle. You can also find a contractor and distributor in your area on their website. I have used Western Roofing before in the Los Angeles area and they are very good.
Sherry
August 10th, 2008 at 2:10 pm
What about concrete roof tiles? I have begun research and they seem to be pretty good. Any advice?
Shayna Prunier
August 11th, 2008 at 9:45 am
Concrete roofing tiles are a good choice for insulative properties since concrete is a thermal mass. This will help in cooling and heating costs. The tiles come in lighter colors which might be energy star certified and would not contribute to heat island effect. Concrete would also be recyclable. However, the trade-offs to consider are that concrete has a very high impact on the environment in its manufacturing process, and you will need to make sure that your roof is structurally sound enough to handle the weight of concrete tiles. There are a few manufacturers making concrete tiles, you could ask them about their manufacturing process, if they have any recycled content in their mix, and if they come in “cool roof” colors.
commercial roofing contractor
August 13th, 2008 at 8:57 pm
Shayna, your article is great! thanks for sharing this info to us
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January 13th, 2009 at 10:25 pm
[...] remodeling projects — from creating a green roof to simply setting up a composter — are also covered, along with some basic information on [...]
Roof Replacement
February 4th, 2009 at 3:46 pm
I think that green roofing is definitely growing in popularity. My company (based in the DC area) has a portfolio of green options for clients to choose from when selecting a roofing material. It comes with an analysis of green benefits and energy savings hard facts. I expect 2009 to see even more of a jump for the initiative!
roofing shingles prices
March 25th, 2009 at 2:28 am
what a great info post …
Dan Arguelles
May 3rd, 2009 at 8:18 am
An economical retro-fit application over asphalt shingles is the best bet to save some doe! You could save money on demolition and put it towards solar panel or green roof integration because the Artezanos sustainable hybrid retro-fit can integrate both. If you are just looking for a new roof system or something for re-roof , the same system can be used to economize a look with real traditional roof tile while you save half the weight.
If installed properly, this Hybrid Roof Tile System will outlast you and your home!
Jessica
June 17th, 2009 at 10:56 am
I work for a distributor of specialty metal roofing products, and I think this article is spot-on. However, I’d like to bring your attention to some of the newest green roofing technology on the market. I’m thrilled to be part of the launch of the latest and greatest in environmentally friendly roofing - the world’s first solar hybrid roof. The Active Roof is a metal roof system with a fully integrated and invisible solar collection system. It’s the first roof that pays for itself, and it can’t be beat in terms of both homeowner satisfaction and the eco-friendliness. I’d love to share details, feel free to contact us via our website, http://www.activeroof.com.
amber prior
July 25th, 2009 at 8:15 pm
you don’t tell what the best green material is. I was reading the whole thing just to get the best material, but ir turned out i had to go to a different wabsite because you were just explaining the bad materials not to use.
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osay 912
February 4th, 2010 at 9:22 am
This article suggest there were three important things to cover, “When considering a new roof, the two key dimensions you should think about are the material and the color (and, of course, cost!).” You covered the first two, what about the last. I have 60 squares to do, with max $6K going to labor, what’s the wholesale price I should seek for the singles?
Thanks for listening
Alex
March 16th, 2010 at 12:30 am
Very nice post!!!
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