Green Roofing Options Eagle River AK
Certified Contractors Network (CCN)
Certified Contractors Network (CCN)
Green Roofing Options
To determine what makes a roof green, we must first consider what a roof does. First, and primarily, roofs keep rain (and snow) off our heads and off the walls of our houses; second, they keep us safe from fire; third, they add to the curbside appeal of our homes; fourth, they collect water for landscapes; and finally, roofs provide temperature abatement.
Ideally, green roofing materials, which are better for our health and for the environment, would provide all five of these benefits. But it's not always that simple. Often roofing that works well in Florida is not a good option for a home in Colorado. Roofing is one of the most climate-specific materials for building, so you need to prioritize your requirements and make decisions based on what you want a roof to do for your home.
When choosing a roofing material, it's important to consider all the options available, as well as your climate, your home's requirements, and health and environmental issues. Some roofing materials contain carcinogens that can affect the health of a home's occupants. Another concern is re-roofing, which accounts for 78 percent of the total annual roofing dollars spent in the United States. Re-roofing is not only expensive, but can send used roofing materials to landfills, where they can off-gas pollutants and leach toxins into the soil and groundwater.
Here's a quick rundown on today's roofing options with recommendations on which ones might be best for your home:
.�15-year asphalt shingles. For numerous reasons, this type of roofing material is not a good option. Short-lived asphalt shingles are a bad use of oil and are rarely recycled. They are among the most disposed-of building materials. Toxic volatile organic compounds (VOCs) will off-gas from asphalt as the sun heats it; these VOCs can then enter the living space through doors, windows and vents.
. 50-year recycled-content asphalt shingles. At the very least, look for recycled-content asphalt shingles that contain recycled or reclaimed-material slag in their aggregate surface, thereby reducing waste of raw materials during the roofing process. This inexpensive, hail-rated roofing material will last 50 years instead of 15, resulting in less waste sent to landfills and minimizing the hassle of roof replacement. For any type of asphalt shingle, never drink water that comes off the roof or use it for any type of water catchment.
. Lead-free metal roofing. Metal roofing is made from copper, steel or aluminum. Some products contain up to 100 percent recycled material, and most can be easily recycled. Metal roofing is easy to install, and it is fireproof, lightweight and long lasting. Also, unlike all other roofing materials, metal roofs provide rigidity. Metal is the most favorable roofing material used for rainwater catchment systems. In northern climates, snow readily slides off metal roofs, preventing damage caused by ice dams. Metal roofing comes in many shapes and styles, including panels, shingles, shakes and tiles, as well as a wide range of colors and patterns. Because the metal is thin and does not have heat-holding capacity, metal roofs do not radiate as much unwanted heat into the attic as asphalt shingles. Using a white painted or galvanized finish on the metal will further deflect heat away from the roof and attic. On the downside, metal roofing can be expensive.
. Fiber-cement composite roofing. Fiber-cement is made of Portland cement, sand, clay and wood fiber. The product typically carries a 50-year warranty. Fiber-cement composite roofing is durable, fireproof and recyclable. This roofing material can be readily used on standard roof structures. Fiber-cement composite slates or shakes are not recommended in northern regions or at high altitudes because they do not perform well in freeze-thaw climates or in hail-prone areas. Keep in mind that you cannot walk on fiber-cement roofing, and it can be difficult and expensive to replace.
. Clay tile. Clay tile is durable, attractive and very popular in places like California and the Southwest. The corrugated design has a cooling effect on the roofing system, since air is able to flow around it. However, hail can shatter clay tile, so it is not the best option for northern climates. It's also fairly expensive. You cannot walk on it to repair it easily, and it does not work well with solar applications.
. Cast-concrete tiles. Cast-concrete tiles are fire-resistant and look similar to fiber cement roofing. However, they are heavier than fiber cement, so extra structural work is required. Their color tends to fade over time, and freeze-thaw cycles can damage the tiles unless they are specifically formulated to withstand it. The tiles tend to shatter in hail and are expensive to buy and install.
. Slate. Slate is minimally processed cut or split rock. It creates a distinctive look and is incredibly durable. Not only does it have a good fire rating, but properly installed slate roofs can last 100 years or more with only minor maintenance. What's more, it can easily be reclaimed and reused on new building projects. Keep in mind that slate comes only from mid-Atlantic and Northeastern states, as well as from Europe; therefore, depending on where you live, transportation costs can make the material expensive.
. Cedar shake. Many in the greenbuilding industry discourage the use of cedar shake because the cedar is often harvested unsustainably. Although fire-resistant coatings do exist for cedar shake roofing, in general it is a serious fire hazard, making it an expensive option, if not illegal in many areas.
. Recycled synthetic shingles. These expensive recycled rubber and plastic shingles offer an alternative to such roofing materials as cedar shingles and shakes, natural slate, clay or concrete tiles and standing-seam metal roofs. Attributes include durability (guarantees range from 40 to 50 years), excellent hail and wind resistance, and good seismic and sound insulation performance. Insurance companies in several states have responded to their superior hail and wind resistance by offering discounts to homeowners who install recycled synthetic shingles.
. EPDM rubber. EPDM (ethylene propylene diene monomer) rubber is one of the most common types of low-slope roofing material in the United States, primarily because it is relatively inexpensive and simple to install. During and after installation, it doesn't release odors and fumes, as some other types of roofing materials do, which appeals to many homeowners.
. Modified bitumen. Modified bitumen is asphalt that has had modifiers added to it to give it plastic or rubber-like properties. This fairly sophisticated roofing material comes in rolls and is primarily used for slope roofing.
. Hot asphalt. Although it's inexpensive, durable and easily repaired, this is not a great roofing material. Again, it's a bad use of oil, the installation process is highly toxic and it requires frequent maintenance to prevent ultraviolet sunrays from breaking it down.
. Building-integrated photovoltaics (BIPV). These new roofing systems are 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. After the roofer installs the tiles, an electrician connects the roof system to the home's electrical system. Each 100 square feet of BIPV generates about 1 kilowatt of electricity, which is not that much relative to solar panels, making it an expensive form of solar electricity.
. Green roofs. As the name implies, these truly "green roofs are planted with vegetation. Also known as "living roofs, they are protected-membrane roofs with soil and plantings (as well as insulation) installed above the membrane. These systems are encouraged and even subsidized in Europe because they reduce flooding risks and cooling needs. They can detain over half the rainwater from a typical storm, reducing often-high loads placed on sewer systems after rainfall. In addition, a green roof can be a wonderful architectural element that absorbs carbon dioxide and helps reduce building heat gain and urban heat islands.
However, these multilayered green roof systems are thicker and heavier than conventional roofs. Therefore, the roof structure needs to be engineered to accommodate the increased weight of the roof. It must also be watered intensely, and it's expensive.
As you can see, choosing the right roof for your home can be a complicated process. But by evaluating all the options available, considering your location and climate, and keeping in mind health and environmental concerns, you can make sure your final selection is a wise one.
Kim Master is a senior associate at What's Working Inc., a Boulder, Colo.-based greenbuilding consultancy. David Johnston is the founder of What's Working. They're the authors of Green Remodeling: Changing the World One Room at a Time (New Society Publishers).