The expanded Northeast Branch is the 10th branch to open under the "Libraries for All" building program. Paul Thiry, a prominent Seattle architect, designed the original award-winning building. The Miller|Hull Partnership designed the addition and it was built by Graham Contracting Ltd.
For the expansion, the Miller|Hull Partnership valued continuity between the old and new building. They preserved the pavilion-like feel of the original building by keeping the roof peak and avoided installing ductwork along the ceiling.
The roof of the addition is the inverse of the roof of the original building, which complements the original architecture.