Last Friday was a fabulous day for a green roof tour in Seattle with blue skies and warm weather during our trek around the downtown core and over to Seattle Center for a total of 6 roofs. This first post will provide a bit of an overview of the tour with future posts delving further into few of the roofs to include details, lessons learned and more photographs.

The tour, sponsored by Seattle Public Utilities and the Department of Planning and Development, started at the Justice Center Green Roof with the additional ability to look down on the City Hall Green Roof below. As some of the older roofs in the City, the Justice Center Green Roof was completed in October 2002 and the City Hall completed in July of 2003. Since recently moving to Seattle, I joined SvR Design who was actually in charge of the Justice Center Green Roof and after the tour, I wrote a blog entry on the SvR website showing pictures of the roof as it looks 8 years post-installation. Here’s some text from that post about the roof with additional photos below:

The support system is from American Hydrotech and consists of a 6″ profile including insulation, an “egg crate” style drainage/moisture retention layer and a custom soil mix over a multi-layered waterproofing membrane. The planting design by SvR was guided by an image of sunlight reflected in a shallow streambed, much like that of the water feature connecting the Justice Center with the City Hall. The pattern shows through in wavy swaths of greens, blues, and grays.

The City Hall Green Roof, pictured below, was completed in July 2003 by Gustafson Guthrie Nichol using an American Hydrotech sytem and primarily planted with a mix of sedums. The roof was not originally outfitted with irrigation which had to be installed afterward due to Seattle’s summer being mostly without rain, something places like Germany or Chicago don’t experience and unfortunately are the areas putting out most of the research and design/maintenance guidelines in the areas of green roofs. With each roof and each year, we learn more and more about how green roofs function specifically for the northwest, which is why tours like this are so important.

Since planting, the vegetation has since been almost 100% taken over by weeds and according to Peter Jeu, who was luckily on the tour and has provided the maintenance for the Justice Center and City Halls roofs since the very beginning, the roof is now mostly grasses that have blow in and even grow so tall that he has to mow it. They are in process of trying to replant more sedums on the roof but due to the low wall and high winds coming up from the Puget Sound, it’s going to be an ongoing battle.

Next stop, 5th & Madison. This roof is an interesting one because due to the steep slopes of downtown Seattle, this roof actually meets the sidewalk on the uphill side which allows the public to freely meander in and out. A cascading water feature catches the attention of passersby and draws them in and through the site. The roof was designed by Canadian firm Phillips Farevaag Smallenberg.

The roof sits right near the Koolhaas-designed Seattle Public Library and provides a dramatic view of the large glass structure.

Next stop, the green roof at the top of the M Street Apartments that provides an amenity for the tenants. The building and green roof were designed by local firm GGLO.

Below are some views of the pedestrian area with grasses and a wood decking that runs around the perimeter to make the space feel less like a roof and more like a nice outdoor space.

Another interesting addition to the roof atop M Street Apartments is the dog run space and the raised planters for the tenant’s community gardening space.

And just below the M Street Apartments roof, the little green roof on the building next door could be seen.

The next stop on the tour headed over to the two extensive rooftops at the Olive8 building that houses a hotel at street level with condos above. The two roofs, designed by the Berger Partnership, look similar but used two different technologies. The lower used a tray system while the upper one used a rollout sod style, all contain a mixture of sedums. Both were grown offsite and therefore looked nearly mature once installed. For the tray system, the designers decided to fill the trays with a lot of plants in order to allow the plants to grow over the edges. Then the trays were laid out in a running pattern instead of stacked so that there was never an instance where 4 corners came together causing a more visible seam.

After the roof was installed, the restaurant within the building decided they wanted to try to grow herbs on the roof and set a tray with herbs on top of one of the mechanical units as a trial run. If it goes well, they may try to grow more on top of other units.

After a ride on the monorail over to the Seattle Center and up the Space Needle, we hit the last stop looking over at the 5th Avenue N garage roof, the covered parking area next to the future Bill and Melinda Gates Foundation campus. The massive 60,000 sf green roof was designed by Gustafson Guthrie Nichol and was entirely planted in sedums over an American Hydrotech system. Unfortunately, the view from the space needle wasn’t perfect but helps to judge the scale of the massive roof.

all images (c) Lisa Town