By Jenisha Shrestha
This fall, Colby-SawyerCollege in New London, NH dedicated a free-standing sustainable classroom designed and built by students that is one of the first commercial buildings in the state to integrate a straw-bale wall system. I was involved with this one-of-a-kind experience from the beginning.
The classroom is Colby-Sawyer’s latest achievement in its efforts to cultivate a culture of awareness and action regarding sustainability and the environment. It is situated behind the library and next to the college’s organic permaculture garden. It was made possible by a generous grant and the efforts of faculty members in the Environmental Studies Department, most notably Professor Leon-C. Malan and Director of Sustainability Jen White ’90, as well as more than 100 dedicated students and community members.
The college developed three courses to span the construction of the classroom: Shelter and Sustainability in fall 2012, The Living Building in spring 2013, and Project Completion in fall 2013. (Like many construction projects, ours finished a little behind schedule.) Those of us who successfully completed all three courses earned a Certificate in Sustainable Design and Construction.
The courses were taught by Bryan Felice, founding owner of Undustrial Timber Frames LLC. We first began with exploring building science and performance, the design process, natural materials, construction planning and timber frame techniques, and then we designed the building’s features. Our final exam was to present our design to the Town of New London and take part in the permitting process. We passed!
The building features a timber frame structure which we constructed in the second course from the wood of native species sourced from New London and Andover. We calculated, cut and connected all the mortis and joints, and erected the frame in an old-fashioned barn raising community event. That was my first exposure to power tools [See Green Energy Times, Dec. 15, 2013, pg. 32]. The building is designed to obtain maximum solar gain through its passive solar architecture, low-E windows along the convex south wall, and concrete floor for thermal mass. With the goal of educating visitors about various natural building wall systems, this classroom features three wall systems: straw-bale, dense-packed cellulose and straw-clay. As part of an independent study, another student and I helped to construct these wall systems, applied the natural plaster and paint, and built the cob benches that add to the thermal mass and classroom seating.
The north wall consists of six inches of dense pack cellulose and 18 inches of straw-bale insulation which provides an R-value of 52.8. The east wall, with 12.5 inches dense-packed cellulose, has R-46.5, and the west wall’s 15 inches dense packed cellulose has R-57. The south wall, which faces the true south, consists of 12 inches of straw-clay mixture with an R-value of 19.2. A typical wall system has an R-value ranging from 12 to19. Structural insulated panels (SIPS) that consist of an insulating foam core sandwiched between two structural facings, typically oriented strand board, were used for roofing, and that adds to the overall energy efficiency of the building. The typical R-value of ceiling assemblies is about 30, whereas the 12 inch SIPS increase ours to 78. The roof aspect is designed for a photovoltaic system and the lower face will be a ‘living roof.’
The sustainable classroom is now a teacher in and of itself that will be used by the college’s students and faculty, as well as the children at WindyHillSchool, Colby-Sawyer’s laboratory school. The space will also be available to our permaculture garden interns to use as a greenhouse for seedling production and food storage, and for hosting community and alumni events.
Future plans for the building include implementing a permaculture garden design created by Kenneth Camacho ’15 and installing a photovoltaic system with sensors and digital displays inside the building so we can know how much heat the building is gaining or losing.
Eventually, a photovoltaic array will produce electricity to run the two energy-efficient mini-split heating and cooling systems, making the “living” building a NetZero building because it will produce more energy than it uses. It is even possible that the college will be able to sell energy back to the grid.
Participating in the creation of such an innovative and sustainable structure that is used by the entire campus was a great experience.
Originally from Kathmandu, Nepal, Jenisha Shrestha is a recent graduate from Colby-Sawyer College with a Bachelor’s of Science degree in environmental studies. She received certification in Permaculture Design as well as a certification in Sustainable Building and Construction through Colby-Sawyer. Currently, Jenisha works as the Sustainability Fellow for the college.