September 25, 2025

Transforming a Bothell office building into a private K–12 school

Deitch

Besmer

Cornerstone General Contractors recently completed a unique adaptive reuse renovation for BASIS Independent Bothell, a private K-12 school owned by Spring Education Group. This transformation of a 124,637-square-foot commercial office building into a school campus required strategic planning and expertise to repurpose the former office space into a modern educational facility serving students from kindergarten through 12th grade.

Cornerstone, with a background of having constructed more than 80 school facilities in the region, led the critical structural upgrades for the project.

“Repurposing this building allowed us to create a thoughtfully designed, state-of-the-art campus in the heart of Bothell,” said Toby Walker, vice president of schools for BASIS Independent Schools. “Transforming an existing structure gave us the opportunity to reimagine every inch of the space to meet the needs of our students today and in the future, while also making an investment in this growing community.”

Photo by Francis Zera, ZeraPhoto [enlarge]

The school’s retrofits included the addition of more than 6,000 yards of concrete for new footings, and shear walls throughout the building.

Utilizing the former office building required a significant seismic retrofit to change occupancy to an education facility. These retrofits included the addition of more than 6,000 yards of concrete for new footings and shear walls throughout the building. Beyond the seismic renovations, careful thought and planning were put into the layout of the building and how it could best accommodate the needs of a school with classrooms, teacher support areas, a gym, a theatre and a cafeteria. Inhabit Design served as the designer for the project.

The most challenging component of this adaptive reuse was the gymnasium, where portions of two post-tension slabs were removed to accommodate the required ceiling height. This process involved exposing, isolating, de-tensioning and recapturing bundles of existing post-tensioned cables before the level 2 and 3 concrete slabs were safe to remove.

Supporting the load of the fourth floor and the roof where the existing slabs and columns were removed, now stand two 30-ton trusses that were each hoisted into the building in thirds to be field assembled and preloaded.

Photo courtesy of Cornerstone [enlarge]

Two 30-ton trusses were hoisted into the building in thirds to be field assembled and preloaded before installation in the gym.

“It’s exciting when a project leaves people wondering ‘how did they do that?’” reflected Aaron Besmer, Cornerstone’s project manager for the BASIS renovation. “The coordination, sequencing and creative thinking of our entire team — to create a full-sized gym inside this building — made for a very challenging structural scope that was executed incredibly smoothly,” Besmer continued.

Adjacent to the building on both the northwest and southeast sides of the property, the project team made use of excess parking areas to create a new synthetic turf soccer field, basketball court and multi-age playgrounds. A new storm structure was also placed beneath the turf field.

Now the six-acre BASIS Independent Bothell campus features a refreshed building with state-of-the-art labs; specialized classrooms for drama, music, visual arts and engineering; a gymnasium with locker rooms; a café with a warming kitchen; outdoor sports courts and fields; and a playground to support a comprehensive student experience.

Photo by Francis Zera, ZeraPhoto [enlarge]

The most challenging component of this adaptive reuse was the gymnasium, where portions of two post-tension slabs were removed to accommodate the required ceiling height.

The school welcomed its students in early September and plans to grow into its new space, which can hold up to 900 students. The Bothell location adds an 11th campus to the roster for BASIS Independent Schools which has campuses in California, New York and Virginia, as well as one in Bellevue.

“This project highlights the incredible possibilities when you combine innovative construction techniques with adaptive reuse principles,” said Dave Flynn, Cornerstone’s president. “We are proud to deliver a facility that not only meets the unique needs of a private school program like this one for BASIS Independent Schools but also contribute to revitalizing existing infrastructure right here in our Bothell community.”

“This renovation underscores Cornerstone’s dedication to quality craftsmanship and collaborative project delivery for our local educational client partners,” continued Flynn.

This project is one of five local educational facilities that Cornerstone completed this summer for the start of the 2025/2026 school year. The other projects include new schools for Asa Mercer Middle School in Seattle’s Beacon Hill neighborhood for Seattle Public Schools, and Evergreen High School in the White Center community in Seattle for Highline School District; a new gym building and track for Explorer Middle School in Everett for Mukilteo School District; multiple campus additions and renovations for Newport High School for Bellevue School District; and new locker rooms at The Bear Creek School in Redmond.

Melanie Deitch is marketing and communications manager. Aaron Besmer is project manager for Cornerstone General Contractors.

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