Boston’s third tallest building and the tallest residential tower in all of New England was recently announced as the Council on Tall Buildings and Urban Habitat’s (CTBUH) winner in the Best Tall Building 200-299 Meters category. Located above the heart of the Christian Science Plaza, One Dalton is a 61-story, 851,000-square-foot mixed-use development consisting of 215 guest rooms and 171 condominiums.

The project includes a hotel with dedicated hotel lobby, retail, café, restaurant, ballrooms, meeting rooms, gym, and spa; residential condominiums with fireplaces, balconies on upper floors, private lobby, commons room, theater, kids’ playroom, golf simulator, and pet grooming.

Winners of CTBUH’s annual Award of Excellence competition were announced in five regional categories, five height categories, categories focused on engineering, and other functional categories. Each winner presented to and was judged by multidisciplinary juries comprised of CTBUH members from across the globe with expertise in architecture, engineering, construction, and other disciplines.

“With the United Nations projecting nearly 70 percent urbanization by 2050, the demand is growing for healthier, more sustainable, and socially just urban environments — tall buildings and other smart, resilient approaches to population density are an integral part of the solution,” said CTBUH CEO Javier Quintana de Una. “The projects selected for our yearly Award of Excellence competition represent the most advanced concepts and technologies currently employed around the world.”

One Dalton — designed by Pei Cobb Freed & Partners, along with CambridgeSeven Architects — is nestled between two Boston neighborhoods of vastly different scales: the Back Bay, with its 19th century townhouses, and the city’s High Spine, the largest-scale complex in Boston. According to Andrea Day, Associate Partner at Pei Cobb Freed & Partners and Project Manager for One Dalton, one of the challenges of this project was the need to integrate One Dalton into both of these neighborhoods.

“Our firm strongly believes that it is important for a tall building to be a good neighbor, and for this particular site, the neighborhood context is richly complex,” Day said. “We have the small scale of the Back Bay townhouses and Christian Science Center, combined with the terminus of the downtown spine of tall office buildings. It needed to integrate within this context and most importantly address, by means of its podium base, how a tall building meets the ground and integrates the human scale with the tower scale.”

The answer to this challenge came in the way of a podium at the base of the tower, rising to the 70-foot height of the nearby townhouses. The podium uses warm, gray granite and clear glass shaded by wood louvers to give the tower a sense of welcome and openness at the ground level. There is also a small park opposite the hotel entry that, along with the scale of the podium, integrates the building with the surrounding neighborhood.

Other challenges included logistical site constraints and the need for operable windows on a 760-foot-tall tower.

One Dalton was built on a site with an unusual equilateral triangular shape, which was formed as a product of the former railway lines and Massachusetts Avenue. This led to the design of the building also taking on a triangular shape, with softened sides and curved corners. The general contractor for the project, Suffolk, addressed the logistical site constraints with extensive preconstruction planning for the construction management plan. While working in the extremely tight site, the team also safely delineated pedestrian routes and routed traffic around the area.

The need for operable windows and views for One Dalton’s condominiums resulted in the team designing the upper portion of the exterior wall with surface incisions. The incisions offer views in two directions and allow for operable window sashes for the condominiums located on the top 40 floors of the building. The glass fin between the incisions protects the window sashes from precipitation and Boston’s high winds.

“One Dalton really emphasizes the importance of the human scale of tall buildings in urban habitats. … I think the many user-centric aspects of the design, and how the tower presents itself as a good neighbor really make this a unique project and special addition to the Boston skyline,” Day said.

• Architects: Pei Cobb Freed & Partners and CambridgeSeven Architects
• Owner: Carpenter & Company, Inc.
• General Contractor: Suffolk
• Structural/MEP Engineer: WSP
• Landscape Architect: Michael Van Valkenburgh Associates, Inc.
• Civil Engineer: Mitch Engineering