35 Stone is a five-story, mixed-use development that stands as a model of environmental responsibility in Seattle’s urban core. The building includes 103,000 SF of office space, 4,700 SF of at-grade retail and restaurant space, and three levels of below-grade parking. MacDonald-Miller delivered integrated MEP solutions across mechanical, plumbing, and controls:

Mechanical – Installation of Trane Air Source Heat Pumps (ASHP), Heat Recovery Chillers (HRC), and a rooftop Dedicated Outdoor Air System (DOAS) unit to provide efficient ventilation and supplemental heating through electric backup boilers.

Plumbing – Restrooms on each level, garage-level shower rooms, and a heat pump domestic hot water system, tied to the cistern-driven rainwater harvesting system.

Controls – A Building Automation System (BAS) enabling real-time monitoring, energy optimization, and compliance with sustainability objectives.

The project is part of the Seattle Living Building Pilot Program, which aims to meet the highest sustainability and environmental standards. The building features a hybrid mass timber construction and a state-of-the-art 250,000-gallon rainwater harvest cistern. Through our integrated MEP solutions, we helped create a functional, efficient space and a model of environmental responsibility.

evolution
Weber Thompson
Sellen
Coughlin Porter Lundeen