Zero-energy classroom Earns Praise in CA
Marin Country Day School’s philosophy is to teach and instill a love of nature by living in it. And now the Corte Madera, Calif., elementary and middle school can do so in the first zero-energy classroom building in North America.
Situated on 35 acres — within its own watershed that runs from the ridge of Ring Mountain to the San Francisco Bay — the independent co-ed school has been educating students since 1956. With a vision to create a library and classrooms that would not simply be a structure of learning, but become part of the curriculum, MCDS enlisted San Francisco-based architecture firm EHDD and Richmond, Calif.-based general contractor Oliver and Co. to achieve their goal of emphasizing buildings and landscapes equally.
The two-phased $25 million project, which was completed in December 2009, was so successful, it earned LEED Platinum certification by the United States Green Building Council.
“It’s completely in line with our mission to work toward a better world,” says Ann Borden, MCDS director of admissions. “Research shows that excellent indoor air quality, acoustics and daylighting create learning environments in which students are more focused and alert, and miss fewer days of school.”
MCDS and EHDD developed a 25-year campus master plan that enabled the school to find appropriate solutions to its short-term space and program needs while keeping in mind its long-term goals.
“Over the years the school has grown in the size of our student body and staff,” says Borden. “We continually assess and evolve our curriculum and have added a number of new or enhanced programs to support student learning and advance our mission. As a result, we were experiencing acute space shortages for existing programs, as well as constraints on future program growth.”
Faculty members also noted opportunities for new ways of working with its 540 students that would flow from larger classrooms, and pointed to the lack of a faculty workroom/lounge as limiting opportunities to discuss curriculum and new ideas.
“Our recently completed construction project addressed these immediate needs as well as incorporating sustainable building practices and supporting our strategic initiatives — environmental sustainability, technology and community connections — and programmatic goals for educating students in a rapidly changing world,” says Borden.
One fundamental design decision for the project was to build only within the previously developed footprint of the campus and not encroach on the hillsides or other natural areas of the surrounding site. New buildings were built on infill sites or on sites created by deconstructing existing buildings, which provided for a denser campus by developing two-story elements where one-story elements once stood.
Construction on the multi-phased master plan began in 2007 and included 33,000 square feet of new construction and a series of renovations. Step (or phase) 1 on the west side of the campus, which is LEED Gold certified, included construction of a multipurpose room annex for community meetings; a kitchen expansion; new and renovated music classrooms; a recording studio and practice room; faculty lounge and work room; transportation and custodial space, as well as an industrial arts area. There are also new administrative offices and enhanced areas for outdoor learning and environmental sciences.
LEED Platinum certified Step 2 on the east side of the campus, which began in July 2008, consisted of the new zero-energy Learning Resource Center.
General contractor Oliver and Co. demolished the library, classrooms and studio buildings, but recycled 85 percent of the materials. Upper school classrooms were enlarged and there are new second grade classrooms, a new lower playground and an expanded step-up area courtyard.
Tom Angelo, executive vice president for Oliver and Co., cited the short construction schedule as the main challenge. For instance, Step 1 commenced and was completed while the school was occupied, including summer months. This required enhanced security requirements and safety checks due to the presence of students and teachers.
“Phase 2 work was land locked by existing school buildings,” he adds. “The only access was over an existing creek. Therefore a temporary bridge had to be designed, engineered, permitted and built to allow concrete trucks, pump trucks, water trucks, drilling rigs, transport trucks, excavators and cranes to cross over the creek in order to access the site — all without the slightest interference or damage to the creek and environment.”
Of particular importance was the restoration of the school’s creek to a more organic state. This involved removing a concrete channel, widening the bed and lowering the peak level by nearly two feet. A series of pools along the water’s course were added to further slow its progress to the bay and prevent erosion.
“Many precautions were put in place prior to starting the project,” says Angelo. “The creeks were checked and monitored on a daily basis to ensure compliance to all codes and regulations. And we constructed a new rock-fall-protection fence on a very steep hillside with absolutely no access for heavy equipment. Therefore all work was performed by small portable equipment.”
Star Pupil
Without a doubt, the centerpiece of the entire project is the 13,600-square-foot Learning Resource Center that houses the library, high-performance classrooms, art studios and student services — with the goal of reaching net-zero energy.
Reaching zero-energy essentially means that a building consumes less energy annually than is produced onsite. Zero energy is also the new benchmark for energy performance, exemplifying how buildings should be designed in the future and to reach California state climate change goals.
The center’s main entry — on the west elevation of the two-story structure — encloses an atrium, stairs and an art gallery behind a glazed façade. Low-emissivity glass and deep louvers prevent solar heat gain, while allowing natural light in and views out to the landscape. The energy produced at the school by a photovoltaic solar array will be more than the center will consume.
“The main strategy was to reduce our energy usage as aggressively as possible and then make up the difference with renewable energy sources — in our case photovoltaics,” explains Ken Powelson, EHDD project architect. “Without reducing our energy consumption, we would not be able to cover our energy needs with photovoltaics within any reasonable footprint. Many of our energy-reduction strategies — such as extensive use of natural daylighting to reduce the dependence on electric lighting — actually increase the comfort and livability of the space. Energy reduction does not have to impose hardships on users.”
As for the challenges encountered, Powelson says many of the team’s plans required extensive integration of design strategies among various consultants and client support.
“The reliance of natural ventilation as a cooling strategy, for instance, required the client to understand that the campus facilities and users would have to be involved in maintaining the building to optimal comfort levels.”
Natural ventilation required the extensive collaboration between the architect and the mechanical engineer, Stantec, to ensure that the buildings were narrow enough to allow effective cross-ventilation and had enough operable windows in the correct locations. It also required the collaboration of structural engineer, Tipping Mar, to make sure there was enough concrete in the slabs to provide sufficient thermal capacity to absorb the required amount of heat energy.
Energy use can be computer monitored in real time to improve building operation and provide students with information on their own environmental footprint. Additionally, rainwater is collected from the roofs and stored in an underground 15,000-gallon cistern that feeds graywater to toilets and acts as a heat sink to cool the building. Water travels through pipes in an in-floor radiant cooling system that uses roughly ten percent of the energy of a traditional compressor.
LEED Status
Achieving LEED certification is no easy feat: Gold requires 44 points, while Platinum requires 58 points, a substantial increase considering that some points are much more difficult to achieve than others.
“Essential to our strategy was to gain all 12 energy-reduction points,” says Powelson. “Many of our energy strategies contributed synergistically to our LEED goals. For instance, natural ventilation was a renewable energy strategy that helped reduce our energy consumption as well as provide occupancy comfort and greater indoor air quality — and an increased ventilation point.”
Daylighting and a reduction in electric lighting also provided multiple points for energy reduction, while stormwater design and reductions in irrigation water use were complementary strategies.
“With so many moving parts and such high LEED goals, timing was always the largest obstacle,” says Borden. “Any large-scale construction project can be expected to encounter obstacles, but we were fortunate to complete the project on schedule and within budget.”
Adds Scott Shell, EHDD principal in charge, “It’s inspiring that the school itself became a teaching tool. Ultimately, the new buildings are both a physical manifestation of and an ongoing inspiration for our commitment to creating ecologically literate students and creating transformative new curriculum around educating for sustainability. As students and adults will attest, they’re also some pretty cool places to hang out and connect.”