Paxson Fay

Adaptive-reuse projects often reveal hidden potential inside historic structures, but they also expose the technical and regulatory complexity of adapting buildings to contemporary uses. Populus Seattle, a 120-room boutique hotel located in the historic 1907 Westland Building in Seattle’s Pioneer Square neighborhood, illustrates how thoughtful design, collaboration and creative code interpretation can unlock new life for aging structures.

Constructed as a steam supply warehouse, the building’s heavy-timber structure and brick-masonry envelope embodied the industrial heritage of Pioneer Square. While those qualities give the building its character, they also posed significant challenges when converting the space into a modern hospitality destination. Deep floor plates limited daylight and ventilation; the structural system required seismic upgrades; and zoning regulations restricted rooftop uses.

By preserving the building’s heavy-timber framework, innovatively applying new mass-timber building codes and carefully integrating structural upgrades, the team reimagined the warehouse as a vibrant hotel while maintaining its historic identity.

Adaptive Reuse in a Historic District

Pioneer Square is Seattle’s oldest neighborhood and one of its most historically protected districts. Many of its buildings date to the late 19th and early 20th centuries, but redevelopment has historically been slow because of the complexity and cost of renovating aging structures.

The Westland Building exemplified these challenges. The structure had been modified several times over its lifespan, including a 1979 conversion from warehouse to office use that introduced a narrow interior lightwell and inserted an elevator into the center of the building. Although these interventions helped adapt the building to office use, they compromised the original structural rhythm and left the interior spaces poorly suited for hotel programming.

The design team approached the project with a guiding principle: preserve the historic structure wherever possible while introducing strategic architectural interventions that would support modern hospitality operations.

Working within the National Park Service’s Historic Preservation Tax Incentives Program, the team evaluated each modification against federal preservation standards. Interventions were designed to remain reversible whenever possible and to clearly differentiate new elements from historic fabric.

By retaining the original brick façades, Douglas fir heavy-timber framing and exposed structural decking, the project preserves the building’s industrial character while dramatically extending its functional life. The team worked with the City of Seattle Department of Neighborhoods Pioneer Square Preservation Board to ensure the renovation fit within the historic standards of the neighborhood for preserving historic sightlines and activating street-level uses.

Bringing Light into the Deep Floor Plate

One of the most significant design challenges involved the building’s deep floor plates. Industrial warehouses were designed for storage and manufacturing, not for spaces that require daylight and exterior views. For a hotel, however, all guestrooms must have access to natural light.

The solution was to expand the building’s existing lightwell—cut into the structure during the 1979 renovation—into a larger central atrium, known as the Sky Court, where 16 guestrooms could be located facing inward, away from the perimeter windows.

This expanded volume now serves as the organizational heart of the building. It draws daylight and fresh air deep into the interior guestrooms and brings natural illumination into the lobby and restaurant spaces below through a large skylight.

Creating the Sky Court required careful structural planning. Timber joists removed from other parts of the building during construction were salvaged and reused to support the skylight framing. This approach minimized the need for new materials while restoring structural continuity lost during the 1979 modifications.

The resulting space not only improves daylighting, but also creates a visual connection through multiple hotel levels, reinforcing a sense of openness within the historic structure.

Seismic Strength with Minimal Visual Impact

Like many historic buildings in Seattle, the Westland Building required substantial seismic upgrades to meet modern safety standards for hotels. However, introducing new structural bracing into a historic timber building can easily compromise its historic architectural character.

To address this challenge, the project team relocated the building’s vertical circulation core. This strategic move allowed the new elevator and stair system to function as a key structural element resisting lateral seismic forces.

By integrating seismic reinforcement into the circulation core, the design avoided the need for intrusive diagonal bracing at the historic façade that would have disrupted guestroom layouts or obscured the historic structure.

Additional concrete shear walls were inserted along the inside of alley-facing elevations where they would have minimal impact on the building’s historic street façades. These targeted interventions significantly improve seismic resilience while preserving the visual integrity of the original architecture.

Applying Mass-timber Code to a Historic Structure

One of the most innovative aspects of the project involved the application of Seattle’s recently adopted mass-timber building codes. These codes—developed primarily for new construction—allow for taller mass-timber buildings by requiring higher fire-resistance-rated structural systems.

For Populus Seattle, the design team explored how these code requirements could be applied to the building’s existing heavy-timber frame through careful consultation between the architect, fire-code consultant and the structural engineer. As the first project to apply the new mass-timber codes to an existing heavy-timber building, the team developed a code report that showed a strategy for compliance to formalize approval of this methodology with the City of Seattle.

The team determined that the substantial size of the original Douglas fir beams and columns could meet the required two-hour fire-resistance rating under the mass-timber code when paired with the reduced structural loads associated with hotel occupancy compared to warehouse use. This allowed the building to be classified under a Type IV-C construction-type designation, which permits exposed structural timber while maintaining required fire performance up to 6-stories tall with assembly and hotel use.

Achieving this designation required detailed analysis and careful coordination between the architectural and structural teams. Existing cast-iron connectors and joist hangers required two-hour fire protection to meet the new mass-timber code. The team addressed this requirement through a combination of spray-applied fireproofing, where the connections were hidden, and custom-fabricated painted drywall wraps, where visible to the public.

This hybrid approach allowed the historic timber structure—including the exposed car decking—to remain visible throughout the hotel interior while still meeting stringent life-safety requirements.

Unlocking the Rooftop

Applying the mass-timber codes also made it possible to introduce a new rooftop hospitality space—an amenity increasingly expected in urban hotels but historically prohibited in Pioneer Square.

At the same time that the design team was navigating building-code requirements, the development team worked with city officials to amend local zoning regulations that previously prohibited rooftop food and beverage services in the neighborhood.

The resulting policy change cleared the way for Pioneer Square’s first rooftop bar, providing expansive views of the surrounding district and the nearby waterfront, as well as creating a destination for hotel guests and local visitors.

Beyond its role as a guest amenity, the rooftop space represents a broader precedent: demonstrating how adaptive reuse projects can work within evolving regulatory frameworks to expand possibilities for historic buildings.

A Catalyst for Neighborhood Revitalization

Populus Seattle is part of the broader RailSpur redevelopment, a micro-district designed to reactivate a historic rail corridor and network of alleyways in Pioneer Square. The hotel’s new alley-front restaurant and outdoor dining enclosure add to other alley-facing food and beverage establishments within RailSpur, activating the once-overlooked passageways between buildings.

One of the project’s most unusual engineering challenges involved constructing the outdoor dining enclosure directly above an active Seattle City Light transformer vault. The structural system was designed so a portion of the roof can be removed in the future to allow maintenance or replacement of the transformers below without dismantling the entire structure. The existing windows around the exhaust vent for the transformer were required to be improved to meet an increased fire rating because of their unavoidable proximity on the constrained site.

This careful coordination between architecture, engineering, and city infrastructure demonstrates the complexity and opportunity of working within dense historic urban environments.

A Model for Hospitality Adaptive Reuse

Populus Seattle demonstrates that historic preservation and contemporary hospitality design can work together to create buildings that are culturally meaningful and economically viable.

By preserving the building’s heavy-timber structure, creatively applying mass-timber codes and strategically integrating seismic and structural upgrades, the project extends the life of a historic warehouse while introducing new vitality to Pioneer Square.

As cities seek more sustainable development strategies, adaptive reuse will play an increasingly critical role in shaping urban growth. Projects, like Populus Seattle, show that with thoughtful design, technical collaboration and regulatory innovation, historic buildings can be reimagined to meet the needs of the present while preserving the stories of the past