The Waynflete School, in existence since 1897, now inhabits a 3-acre campus in a historic district in Portland, Maine. The independent school’s students range from early childhood to 12th grade. Over the past couple of decades, Waynflete’s Middle and Upper Schools have undergone renovations and additions, but the Lower School spaces had yet to be similarly transformed—until this fall. The new 23,000-ft2 Lower School facility, designed and built to meet the Passive House standard, opened its doors this past August.
Architects Austin Smith and Julia Tate of Scott Simons Architects worked with the school’s building committee to help them define the overall project goals and their sustainability goals in particular. Early on in the process, the architects brought in sustainability specialists from the engineering firm Thornton Tomasetti. These specialists were instrumental in developing a sustainability grid to compare and contrast different certification programs and standards, as well as a cost analysis of the premium for Passive House over a conventionally built facility. “Passive House was appealing, because it is targeted, tangible, comfortable, and you can’t game the system,” says Smith. Further analysis revealed that the cost premium for Passive House would pay back through energy cost savings in just six years and three months. “That was a no brainer,” he adds.
The building’s design took shape based on Waynflete’s teaching philosophy, which emphasizes a small teacher-student ratio, and the neighborhood’s mostly residential, historic aesthetic. Its white coursed exterior and gabled elevations echo nearby forms.
The shapes of the four classrooms, which house an average of 50 students in each combined-age class, accommodate smaller groupings of 8 to 16 active learners. Each classroom area has its own form tailored to the students’ ages and abilities; the kindergarten through first-grade classroom, for example, features small lofts for playing, reading, and resting. Window patterns and placement were structured so as to optimize daylighting, specifically the morning sun, while preserving eye-level views for the young occupants. The facility also includes a library, an innovation space for both class use and after-school programs, an art studio, and an amphitheater for all-school Pachangas or sing-alongs.
The new building adjoins two existing structures, augmenting the typical Passive House detailing challenges, as did the three different geometries required to create the breakout spaces. The entire design team held many meetings, especially during the construction doc phase, to work out constructible details. The design team credits much of the project’s success to the input received from Wright Ryan Construction, Becker Structural Engineers, Woodard and Curran, and Allied Engineers.
The basic structure consists of an insulated steel moment frame. The largely exposed structure is enclosed with a wall assembly utilizing 8-¼-inch structural insulated panels (SIPs) of graphite-enhanced polystyrene to maximize thermal performance. These panels, along with a vapor-permeable air barrier membrane adhered to the exterior of the SIP, secure the building’s desired airtightness. The foundation slab is insulated with 4 inches of rigid XPS foam to attain an R-value of 20. The R-60 roof assembly also includes SIPs topped by an insulated, vented nailbase panel and standing-seam metal roofing, chosen for its durability.
The exterior siding is masonry veneer at grade level, with the upper floors clad in a rain screen system covered with fiber cement panels. The R-values of these walls range from R-45 to R-56, depending on whether they are masonry or fiber cement clad. All of the exterior materials were selected for their longevity with an eye to reducing or eliminating maintenance. Visual compatibility with the surrounding context of the existing campus and neighborhood was also important.
The exterior doors proved to be unusually challenging, as they had to meet Passive House requirements and Americans with Disabilities Act specifications, and accommodate the needed hardware for key card access. After much analysis, an aluminum storefront-type door was found that met all these criteria.
The all-electric building is being ventilated primarily with a centralized ERV—an approach that sounds simple but required solving various special ventilation needs. The art room includes an electric kiln, for which the direct venting had to be carefully sealed. The school’s laundry facilities provoked some deliberations; it was eventually decided to use ventless condensing dryers. Venting solutions for the building’s series of kitchens also took research, and the self-contained recirculation hoods that were chosen had to be preapproved by the fire department.
Supplemental heating and cooling is being provided by air source heat pumps. Heat pump water heaters supply the domestic hot water.
This facility that has been years in the planning is finally opening its doors. This state-of–the-art building is providing the structure within which Waynflete can deliver on its promised balance between communal and individual learning experiences.
|Heating energy||Cooling energy||Total source energy||Air leakage|
|5.1 kBtu/ft²/yr||1.4||35.8||0.5 ACH₅₀/ft² (design)|