In the summer of 2009, the board and administration of the Bertschi School, an independent pre-kindergarten through fifth-grade school in Seattle, weren't quite ready to begin the science building that was the last component in their long-term master plan. The year before, they had achieved LEED Gold certification for a facility for art, music, and physical education that opened in 2007, and they were still raising the last of the funds required to pay for the $3.4 million project. "We have a very small donor community," says Stan Richardson, director of technology and campus planning at the 235-student Bertschi, which occupies a city block in the Capitol Hill neighborhood.
Location Seattle, Washington (Cedar River–Lake Washington Watershed)
Gross area 1,425 ft2 (132 m2)
Completed February 2011
Annual purchased energy (based on utility bills) 9 kBtu/ft2 (105 MJ/m2)
Annual carbon footprint (based on utility bills) 2.4 lbs. CO2/ft2 (12 kg CO2/m2)
TEAM & SOURCES
Structure Matheus Lumber FSC-certified timber, Roseberg Forest Products FSC-certified dimensional lumber, Premier Building Systems FSC-certified structural insulated panels
Metal/glass curtain wall Kawneer 1600 series
Skylights CrystaLite 86200 Skylights
But then Stacy Smedley and Chris Hellstern, two associates in the local office of KMD Architects, made Bertschi an offer: KMD would assemble an architecture and consultant team that would provide design services free of charge. The contractor Skanska USA was also willing to waive its fees for preconstruction services, eliminate its profit margin, and donate some of the materials. For its part, the school would be responsible for construction costs and had to agree to target Living Building Challenge (LBC) certification—no small feat, since there were not yet any buildings that had earned the "beyond LEED" designation.
Bertschi jumped at the chance even though LBC, which was launched in 2006 by the Cascadia Green Building Council and is now administered by the International Living Future Institute, entails satisfying a host of tough-to-achieve but mandatory "imperatives," including net-zero energy and water operations, making it the most stringent green-building certification program. LBC "seemed like a perfect fit for a science building," explains Richardson, since it would allow students to see and touch sustainable practices in action.
At just over 1,400 square feet, the building is a completely different scale than the typical work in KMD's portfolio, which includes health-care, corporate, and institutional projects. However, the diminutive science wing was ideal for testing out the demanding certification system. It was a "research project," says Smedley. For Nathan Miller, a senior energy analyst with MEP engineer Rushing, one of the 13 firms making up the pro bono design collective, the project provided the chance to "get our feet wet" with LBC.
At Bertschi the designers created a two-room structure which was completed in February 2011 and cost the school about $930,000. It occupies the former site of a basketball court and extends from the north face of a church that Bertschi has converted into a school building. This new wing comprises a cedar-clad, butterfly-roofed classroom and an adjoining "ecohouse"—a double-story greenhouselike space for earth studies and experiments—defined by a curved facade of high-performance glazing. The building includes features like a highly insulated envelope, an energy-recovery ventilator, and in-floor radiant heat. But some of the building's more unusual elements were inspired by a "wish list" that the students developed with their science teacher. One child wanted a river to run through the classroom. This desire became the starting point for a glass-covered rainwater channel recessed in the concrete floor. Another wanted a "room where something is always growing"—an idea from which the designers developed a wall for the ecohouse interior planted with five different species of tropical plants.
Both the channel and the living wall are key components of the building's water cycle. For instance, the outflow from the classroom sinks supplies the living wall's drip-irrigation system. The plant material evapotranspires all of this graywater, keeping it out of the municipal treatment system. The recessed channel, meanwhile, carries runoff from the building's roof and that of the neighboring church to a pair of underground cisterns. One stores water for irrigation, and the other, which is connected to filtration and ultraviolet-treatment equipment, collects water that could potentially be recirculated to the classroom sinks, if and when local Health Department regulations change to allow such water to be designated as potable. In the meantime, the second cistern serves as backup to the irrigation system.
One particularly time-consuming aspect of the project was identifying materials that comply with LBC's sourcing mandates. These require that products be obtained within a certain radius of the site and prohibit use of potentially toxic chemicals or substances on the system's so-called red list, many of which are common in building materials. Five team members were devoted full time to materials research, according to Hellstern, who estimates that an average of eight hours was invested in vetting each product specified.
The creators of LBC envisioned that the sourcing requirements would prompt manufacturers to examine and ultimately modify their supply chains. And the Bertschi team saw evidence that the certification system is effecting such change. For example, after selecting a skylight on the basis of thermal efficiency and other performance criteria, the architects learned its frame was made of PVC—one of the 14 substances on the LBC red list. Motivated by a desire to have the skylight included in the project, the manufacturer offered to custom-fabricate an aluminum frame with no extra charge. The PVC-free component is now part of its product line. "This was one of the project's little victories," says Smedley.
Meeting the certification system's net-zero-energy imperative, which requires that all energy needs be handled on-site on a net-annual basis with renewable sources, has been an ongoing hurdle. The building opened in early 2011 relying on the power supplied by a 12.1-kW photovoltaic array on the roof of the converted church. But the first months of occupancy were unusually cold and dark, suppressing electricity production while increasing demand. In addition, the team discovered that a number of systems, including the heater that ensures the proper functioning of the composting toilet and the boiler that supplies hot water to the radiant floor, were consuming more energy than anticipated. So in September 2011, contractors added another 1.8 kW. But after this also proved insufficient, the school increased generating capacity to 20.1 kW this past June. Designers expect that the building will now operate as a net-positive energy producer and anticipate submittal of the performance data required for LBC certification by the end of the year—a schedule that puts the project in the running to become the fourth Living Building in the world.
Regardless of the outcome of the certification process, it is clear that the little project has already had a big impact on the participants' practices. KMD, for example, has eliminated PVC from its specs firm-wide and is next tackling halogenated flame retardants, another substance on the LBC red list. And Rushing is working on the design of an aggressively green office building for Seattle. "We most likely got the job because of our Bertschi School experience," says Miller.