Tilt49 / Downtown SeattleWA
How do you build flexible space in an otherwise inflexible environment?

Tilt49 is a 300,000 SF, 11-story office building in Seattle’s bustling Denny Triangle neighborhood. It is part of a larger mixed-use development that also includes the AMLI Arc residential tower.

From conception through design and construction, Mortenson was a trusted partner helping Touchstone Development make the Tilt49 office tower a reality. The non-compete award of the Tilt49 project, based on Touchstone’s experience with Mortenson on the Hill7 project, allowed for cost and schedule efficiencies, including a collaborative Design-Assist approach and powerful trade partner relationships to allow for early selection of MEP partners, and a quick project start.

The project features five (5) levels of below-grade parking that span the entire block between Stewart and Howell. Upon entering the building, retail spaces, including three pop-up shops with flexible leasing options, occupy the ground level to activate and unify the pedestrian experience. The ground level also houses conference space. Above, eleven (11) floors of Class-A office space boast floorplates that efficiently adapt to evolving workplace trends and tenant requirements and provide a flexible office environment.

The team also incorporated unique features into the building to enhance tenants’ well-being, including circadian lighting and extensive daylighting, open space amenities, above- and below-grade bike parking, locker rooms, and a communicating stairway in the lobby with environmental graphics to encourage movement throughout the building. There is also a 7,000 SF rooftop deck for tenants to enjoy on the LEED Gold-certified tower.

During construction, Mortenson’s team collaborated closely with the two neighboring contractors to ensure everything ran smoothly and safely, from material deliveries to tower crane swing studies, ensuring safe sharing of air space. With the alley between AMLI Arc/Tilt49 and the neighboring Kinects project just 18 feet wide, the deep excavations required to create their foundations threatened the stability of the soil between them. Ownership agreed to share the same trade partner to design the shoring systems and installation sequences to stabilize the alley. The resulting approach involved excavating the Kinects site first and threading rods that extended from their shoring wall to the AMLI Arc/Tilt49 site, which Mortenson gradually tied into our shoring wall when excavation began.

Mortenson’s team also successfully incorporated significant Amazon tenant improvement changes within the original schedule, showcasing the project team’s adaptability and commitment to meeting the needs of its tenants.

Facts And Figures

Touchstone Development


300,000 square feet

The Team