What Is a Green Roof and Are They a Good Idea in Seattle?
A green roof, also known as a living roof, is a roof of a building that is partially or completely covered with vegetation and a growing medium planted over a waterproofing membrane. It may also include additional layers such as a root barrier, drainage and irrigation systems.
Some people advocate for the inclusion of more green roofs because they:
Absorb Rainwater: Green roofs reduce runoff by absorbing rainwater, decreasing the amount of water that ends up in sewer systems during heavy rains.
Provide Insulation: Green roofs provide natural insulation, which can help regulate the temperature of the building, reducing energy costs.
Combat Heat Island Effect: In urban environments, green roofs help reduce the heat island effect, a phenomenon where cities become significantly warmer than their surrounding rural areas due to human activities and the prevalence of heat-absorbing materials.
Promote Biodiversity: Green roofs create a habitat for wildlife and promote biodiversity, particularly in urban environments.
Improve Air Quality: The plants on a green roof can filter pollutants and carbon dioxide out of the air, which theoretically helps improve air quality in the surrounding area.
Seattle has some climate features that make the area attractive for green roofs – namely mild temperatures and frequent rainfall. Green roofs do require water if they are to stay green, which can make them costly and inefficient in particularly dry places. Their ability to reduce the impact of rainwater in high-density neighborhoods also makes them a potentially attractive roofing alternative in the city.
And, as a community renowned for its green initiatives, Seattle offers special monetary incentives to developers and property owners who adopt green roofs.
It’s Not All Rainbows and Unicorns
Green roofs do sound great – and they offer a unique aesthetic that appeals to some people – but they’re not exactly practical for the majority of Seattle homeowners for a variety of reasons:
- Green roofs are expensive to install
- They require significantly more upkeep and maintenance than a traditional roof
- Structures must be strong enough to support the weight of soil, plants and lots of water (and the other various components, like irrigation and waterproofing)
- While it’s not impossible to install a green roof on a sloped roof, it is more difficult and expensive
Are Residential Green Roofs an Option?
Technically, it’s possible to install a green roof on a home, but they do require additional considerations and mechanisms to prevent soil erosion and to ensure the plants and other materials remain securely in place. Homes might need extra support and retention measures, like terracing or the use of cellular confinement systems.
The steeper the roof slope of the home, the more difficult it can be for plants to establish themselves and for the roof to retain water effectively. Plant selection and design are particularly important for sloped green roofs to ensure the green roof system functions optimally.
The average home simply isn’t built for that kind of roof weight, which includes the weight of the soil, plants and retained water. There may be ways to reinforce a residential roof to handle the weight, but it may be invasive and require costly home modifications.
You would also need to consider the local building codes and HOA regulations if applicable to your neighborhood.
Green roofs tend to be a better and more convenient option for commercial structures that can handle the added weight and don’t require significant modification prior to installation. The flat roofs of most commercial buildings also make them ideal for this type of system.
Although there are cost savings offered by a green roof, like reduced utility and temperature control costs, those savings can be eaten up by installation and structural modification expenses. This tends to be less of an issue for commercial structures that don’t require drastic changes.
You Don’t Need a Green Roof to Be Environmentally Responsible
At Chet’s Roofing & Construction, we appreciate that our clientele is concerned about the local and global environment, and we respect your desire to be responsible in your building and home modification choices. At the same time, we recognize that green roofs simply aren’t a feasible option for the vast majority of homes and homeowners in the greater Puget Sound area.
We offer a variety of roofing solutions that do offer real environmental benefits, like standing seam metal roofing. Metal roofs can last for 50 or more years, meaning they significantly reduce waste from roofing material in landfalls. They can also be manufactured with recycled material and can offer dramatic energy saving benefits through exceptional insulation value.
If you’d like to learn more about ways in which we can install an environmentally friendly roof on your home, call us at (877) 611-1514 for a free estimate.
