BELFAST — Cornerspring Montessori School has announced the opening of its new middle school building, built to accommodate the school’s successful Middle School Program.

Designed by Belfast-based OPAL Architecture and built in collaboration with OPAL Build, a sister company to OPAL Architecture, the middle school building is built to the Passive House standard for energy efficiency. It matches the existing Cornerspring facility, which opened in 2017 and was designed by OPAL and built by GO Logic. The new school was constructed using Cross-Laminated Timber and wood fiber insulation, which OPAL’s sister company Timber HP plans to manufacture in Madison.

The University of Maine Orono is partnering with Cornerspring and OPAL to provide energy, thermal and moisture monitoring of the structure’s ground-breaking all wood structural and thermal construction system.

“Working with Cornerspring to be able to demonstrate, on their Belfast Campus, the first-of-its-kind renewable, sustainable, all-wood construction is an incredible opportunity,” OPAL Architecture’s executive partner Matthew O’Malia said in a press release.

“We are also fortunate to be able to collaborate with the University of Maine on monitoring this project, as we will be able to demonstrate together not only the performance benefits of the next generation of carbon-sequestering, high-performance wood construction, but also the latest innovations Maine’s forest products industry has to offer.”

Cornerspring Head of School Susan Beemer said the Passive House design delivers “exceptional heating and lighting efficiencies, saving us thousands of dollars each year.”

“We’re excited to be one of the first commercial buildings in Maine to use the prefabricated Cross-Laminated Timber with the wood fiber insulation pre-installed,” she said in the release. “Watching the building shell go up in just two days on site was impressive!  We hope the University of Maine study helps inform expanded use of this green-building technology.”

The new Cornerspring Montessori Middle School is built to the Passive House standard. Courtesy of Cornerspring Montessori School

The new building, which includes a science lab and flexible spaces, was integrated into Cornerspring’s Congress Street campus, which is situated on 42 acres of woodlands that offer opportunities for nature-based education.

“We launched our Middle School program two years ago in response to requests from our families, and are delighted with the results,” Beemer said in the release. “With the opening of this new facility, our middle school now has the space to match its program, which encourages lifelong learning by fostering self-confidence and independence at this crucial developmental stage.”

Volunteers from the Cornerspring Montessori community, including parents, grandparents, friends of the school, and the Middle School students themselves, contributed hundreds  of hours to help with the build.

“Volunteers tackled everything from installing the siding to painting to cabinet construction,” School Board President Geir Gaseidnes said. “The volunteer community spirit epitomizes what a Montessori school is all about, and it was critical to our success in completing the build in cooperation with OPAL.”

Middle school students pursue studies in science, the humanities, mathematics, Latin, the fine arts, and physical education and health. Students also participate in a micro-economy project and community service opportunities. The Middle School Program includes a seminar in which students develop critical thinking, communication and analytical skills. The curriculum has been specially designed as a Montessori-driven approach to fulfilling the needs of students preparing to enter high school.

Cornerspring is accepting new middle school students, ages 12 to 14, for the current academic year and for the 2022-23 program. Families interested in learning more can call 338-5800 or email

Artist’s rendering shows the new middle school (right) on the Congress Street campus in Belfast. Courtesy of Cornerspring Montessori School