STS Construction Services is proud to have delivered Keystone Apartments, a five-story mixed-use development in West Seattle’s South Delridge neighborhood. Transforming a site previously occupied by an auto shop and once slated for a self-storage facility, this project brings new life to the corridor with 74 modern apartment homes and approximately 4,000 square feet of activated ground-floor commercial space.

Designed to support the neighborhood’s continued growth, Keystone Apartments contributes to a more walkable, connected community by thoughtfully integrating residential living with street-level retail. The project reflects a broader shift toward higher-density housing that meets the needs of Seattle’s growing population while enhancing the character of the surrounding area.

Delivered in partnership with Housing Diversity as co-sponsor and Atelier Drome as architect, this project highlights the impact of strong collaboration in bringing well-planned, community-focused developments to life.

Keystone Apartments was completed ahead of schedule and under budget, demonstrating STS’s commitment to disciplined project management, proactive coordination, and the delivery of measurable value to our development partners.