Green roofs can reduce air-conditioning demand, filter dirty storm water, reduce air pollution, and green house gas emissions. They also can be an amenity that attracts residents to pick one multifamily building over another.
Green roofs are becoming increasingly popular, and research into soil mediums and waterproofing has helped overcome some early hurdles when ambitious designs, plant choice, lack of irrigation or a combination of factors left plants dying and green roofs turning brown.
“The focus has shifted from pretty to performance,” explained Vanessa Keitges, the chief executive of Columbia Green Technologies, the firm behind more than 1,500 green roofs in North America, including Amazon’s headquarters in Seattle and the Zella Apartments there, which feature a deck with an herb garden, outdoor kitchen, dog run and plenty of seating. “We’re getting better at fine-tuning the plant palette so you don’t end up with a brown roof. We’ve moved to drip irrigation instead of spray. We’re designing systems that are much easier to maintain. We want them to be goof proof.”
The New York Times reports on some of the best practices for creating green roofs.