Seven years ago architect Rob Harrison, his wife Frith Barbat, and some of their friends from the Northwest EcoBuilding Guild, built a green roof on top of their garage in southeast Seattle. In the intervening years this small 280 sf green roof project has been featured in many publications and on educational tours - it is a great example "of sustainability on a smaller scale in a city full of greening efforts," as Linda Velazquez writes in her current feature story on the project over at Sky Gardens. With photos and an interview with Rob Harrison, Velazquez shares the history of the project from 2003 to the present. This project makes a good case study for developing residential green roofs.
Harrison and Barbat originally conceived of their green roof project as an opportunity to experiment with installation costs and promote residential green roofs. As Harrison says:
“Since it was our own house (rather than a client’s!), we thought it would be a great opportunity to experiment with a less expensive residential alternative to $15/sf proprietary (and warranted) green roof systems used on commercial projects, and so promote the use of green roofs in residential applications.”
The couple has also experimented with appropriate roof plantings. In the beginning the roof was planted with "Eco-Turf (a mixture of baby blue eyes, red clover, yarrow, and fescues) and a variety of drought tolerant sedums," to which they also "added strawberries, nasturtiums and poppies." Now the green roof "has seceded to mostly grasses," to which Harrison expresses some conflicting emotions:
Rob says...in retrospect he would not have introduced any grasses on the roof at all, as the area planted in Eco-Turf has spread over the entire roof and overtaken the sedums, which are still there, but are hard to see. But he muses, ”The wavy grass does have its own attractions, especially in the dry summer here, where it reminds me of the Palouse in eastern Washington.”
To read and see more about this project (and find out whether Harrison plans to keep the green roof naturalized or not,) see the rest of Velazquez's article at Sky Gardens.
"The wavy grass does have its own attractions, especially in the dry summer here..."
I hate to be a killjoy, but this sounds like a bit of a fire hazard to me.