Students ranging from kindergarten through high school were integral to the design of the Marin Country Day School’s green renovation and expansion. They participated in the design process, researched options, documented construction, and monitored results—and taught their parents about the buildings, which comprise 23,094 square feet of new space and 10,646 square feet of renovations, once they were complete. The school, which includes ecological literacy as part of its curriculum, was enhanced with a new library and technology center, art studios, classrooms, and student services offices.
The mild California climate, along with the school’s emphasis on a connection to nature, provided inspiration for many of EHDD’s sustainability strategies. Passive techniques employing natural ventilation and daylighting were used in more than 90 percent of the spaces. Sunshading, landscaping, thermal mass, and air movement provide comfort without sealing students off from the outdoor environment. Thanks to the buildings’ narrow footprints, skylights, and a large clerestory running down the center of the library, daylight streams into the new spaces, greatly reducing the need for artificial lighting. Additionally, tubular skylights were added to existing renovated classrooms.
Jury: “On the numbers, it’s the second-best energy performer in the COTE Top Ten, but in addition to its performance, we just thought this would be an absolutely delightful environment for learning. What a great place to go to school, both in terms of the setting and the facilities. There also is a strong water story there with replenishing a creek, and the quality of the interior spaces and views were outstanding. It’s an example of great outdoor spaces for kids who are so often confined to classrooms.”
The buildings’ shells made of structural steel frame and exposed acoustic metal deck with concrete fill provide thermal mass for night ventilation cooling. Walls were constructed with 2x8 and 2x10 wood studs (rather than conventional steel studs) to minimize thermal bridging. A small cooling tower evaporates water at night to chill the water to 55 degrees, without having to use energy-intensive, compressor-based air conditioning. This water is stored in a 15,000-gallon underground cistern, and is used the following day to cool the slabs via radiant tubes. These same tubes also heat the buildings with the use of a condensing boiler.
Site work included creek restoration, a new playground, and a large central courtyard. Runoff from the new buildings’ roofs is captured in the 15,000-gallon underground cistern, reducing unfiltered water that would have gone into the creek and wetlands. This captured water is mechanically filtered and used in the buildings’ cooling towers and toilet flushing systems, reducing potable water use. The underground storage tank doubles as a thermal energy storage tank and is several degrees cooler than incoming city water.
Scott Shell, FAIA, principal in charge, EHDD: “The school’s strategic plan aspires to make ecological literacy an integral part of their curriculum, and to reinforce the students’ sense of connection with nature on their very special site. Throughout the design process, we worked to develop synergies between the physical campus and their educational program that would allow students to creatively tackle real, local issues using all the tools at their disposal. To connect students to the site, the design was also conceived around the outdoor spaces as much as around the buildings themselves.”
During an annual sustainability day on campus, initiated by the renovation, students inform the broader community about the school’s green building initiatives. In addition, the campus will continue to serve as a living laboratory for students: An online monitoring system lets students see how the 95.5 kilowatts photovoltaic array output varies with the weather and the season. To help students understand building performance in a tangible way, energy meters monitor individual classrooms’ lighting and plug loads, which offers comparison of one classroom to another. Water meters also allow students to oversee the rainwater collected from the roofs and compare it to overall consumption.
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BY THE NUMBERS
Building gross floor area: 33,740 square feet (including 10,646 square feet of renovations)
Estimated percent of occupants using public transit, cycling, or walking: 55
Percent of views to the outdoors: 97
Percent of spaces within 15 feet of an operable window: 92
Percent reduction of regulated potable water: 76
Potable water used for irrigation: Yes
Percent of rainwater from maximum anticipated 24-hour, two-year storm event that can be managed on site: 30
Total EUI (kBtu per square foot per year): 20
Net EUI (kBtu per square foot per year): 7
Percent reduction from national average EUI for building type: 82
Lighting power density (watts per square foot): 0.17
Third-party rating: LEED Platinum; CHPS Designed School
Total project cost at time of completion (land excluded): $12.5 million
Data and project information provided by EHDD via AIA COTE Top Ten entry documents.