With so many advantages… it’s a wonder they are not the norm.
Green roofs are getting more attention these days with the increased focus on environmentally friendly building trends. While many larger cities in the U.S have embraced the trend over the past few decades, the fact is that roofs made up of vegetative matter have been in existence for hundreds of years around the world.
Outside of the United States, green roofs have become more and more common, and many cities such as Stuttgart, Tokyo, Toronto and Luzern have adopted green roof requirements as part of their building codes. Leonie Meima is an East Bay landscape designer who has studied the development of green roofs and the advancement in related materials and systems. Below she shares some the many benefits that a green roof can offer.
The typical life span for a conventional black or white roof is 20 years, while a green roof can last twice as long. The five thriving rooftop gardens atop the Rockefeller Center were installed in 1936, and in Germany, which boasts more green roofs than any other country, there are green roofs that have been in existence for hundreds of years.
In studies comparing black, white and green roofs, green roofs have been found to be better at providing insulation in both warm and cold climates. They can provide a heat shield effect in hot weather and offer thermal insulation in colder temperatures. In each case, this can help reduce indoor energy use.
In California, where drought has led to an almost year-round fire danger, a green roof composed of succulents can provide a measure of safety. Succulents such as sedum or stonecrops are naturally fire resistant because they contain water (but surprisingly, they don’t require a lot of watering to thrive).
Increased Space for Vegetable Gardening
Depending on your lot size and configuration, your roof area may provide the ideal spot to grown a veggie garden. The roof area usually gets a great deal of sun exposure, and situating a garden on the top of your home can put your edible plants out of reach of deer and other foraging critters.
More municipalities, including state and local governments are offering some form of financial incentive to homeowners who install a green roof. These may come in the form of grants, rebates or tax credits. In addition, PG&E may offer up to $4500 in incentives for a green roof. Working with a professional experienced in green roof installation can help a homeowner learn more about what types of incentives may be available in their area.
Increased Solar Panel Efficiency
Green roofs installed in close proximity to solar panels can boost efficiency due to the air cooling properties associated with plant evapotranspiration. The vegetative matter of a green roof can also decrease dust and airborne pollutants, which reduces the need to clean the panels and can increase solar absorption and efficiency.
Global Community Benefits
In higher density areas such as urban environments, green roofs can diminish the urban heat island effect that results in higher temperatures in cities than in surrounding rural areas. This lowering of temps can diminish the need for air conditioning. The ability of plants to metabolize chemical pollution can improve air quality, which has a number of benefits, including reduced asthma risks. Finally, green roofs create additional habitat for butterflies, birds and other creatures that thrive in a balanced eco-system.
Basic Considerations for Adding a Green Roof to Your Home
Leonie advises that installing a green roof requires an upfront plan. The roof will need to be added as part of a new building project or a remodel where a roof is being replaced or a second story is being added. This is because the proper infrastructure needs to be developed in order to support the roof, which can be anywhere from three inches to 36 inches deep. It is nearly impossible to simply add a green roof onto an existing structure without some sort of retrofit to the underlying support structure.
These are just a few of the economic and ecological advantages of green roofs. If you would like to learn more about green roofs and what might be involved in adding a green roof to your home, please contact Leonie Meima at firstname.lastname@example.org or at 925-202-3683.