5 mixed-use office projects for 2025
By Quinn Purcell, Managing Editor
The editors of Building Design+Construction have collected over 40 recent office and office-to-residential projects, including mixed-use destinations, LEED-certified buildings, and mass timber-built headquarters.
We’re breaking down the submissions into several individual articles to highlight what makes each project special. Because these were all completed in the last 18 months or are currently under construction, these office and office-to-res projects showcase the latest the market has to offer in terms of amenities, trends, and construction techniques.
Below are five of the 40 projects. The full list is coming soon, so stay tuned!
5 Mixed-Use Office Projects for 2025
Here are five mixed-use office projects that were completed in the last 18 months:
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20 Massachusetts Avenue
Washington, D.C.
20 Massachusetts, or 20 Mass, is a repurposed seven-story office building-turned mixed-use destination. It mixes a 274-key luxury Royal Sonesta hotel with Class-A office space, brought together by various amenities: Penthouse conference and lounge spaces, retail and dining, conference facilities, and a fitness facility.
To accomplish this repositioning, the exterior skin and interior of the building were stripped down to the structural frame and concrete floor plates. The subgrade parking levels were retained. Three floors were added, and the footprint was extended one column bay adding a total of 101,000 sf, taking the building to 485,000 sf.
"In an era where carbon footprints are of utmost concern, the careful, even painstaking, reuse of existing buildings is important work. Thanks to the resilience and dedication of the entire team, we are proud of how 20 Mass transforms an outdated building into a destination filled with character, connectivity, and sustainability." — Janki Bhatia, AIA, Senior Project Architect
On the Building Team:
Owner/Developer: The RMR Group
Architect: Leo A Daly
Structural Eng: SK&A
Civil Eng: Bohler DC
MEP Eng: Interface Engineering
Landscape Architect: Lee and Associates
General Contractor: DPR Construction
685 Fifth Avenue
New York, N.Y.
685 Fifth Avenue is the mixed-use conversion of the former Gucci headquarters in New York, N.Y. It has undergone a complete transformation to become Mandarin Oriental’s first exclusively residential property on the East Coast.
Originally constructed in two stages, with the northern steel structure dating back to 1926 and the southern concrete expansion completed in 1999, the repositioning plan presented unique structural engineering challenges to adapt the building for residential use and to support a 10-story addition above the existing composite structure.
The building's mixed vintages required significant modifications to meet residential needs. A re-massing that created multiple setbacks was required to comply with zoning and prevent the ‘canyon effect,’ and to maintain light and air around the building. Multiple top-of-house floors had to be reconfigured to accommodate temporary mechanical systems, a deep rooftop pool, and outriggers to support permanent mechanical systems at the bulkhead.
The undertaking added approximately 20,000 sf of residential space and transformed the office structure into 69 luxury condominium residences.
On the Building Team:
Developer: SHVO
Architect/Designer: Marin Architects
AOR: SLCE Architects
Interior Designer: MAWD
Structural Eng: DeSimone Consulting Engineering
MEP Eng: Lilker Associates
Construction Manager: Rinaldi Group
Bank of America Tower at Parkside
Dallas, Texas
The Bank of America Tower at Parkside soars 30 stories above Klyde Warren Park in Dallas, Texas, standing as a striking new landmark to Dallas’ Uptown district. The central goal of the design was to humanize the office building typology, with an amenity-filled podium that engages the streetscape, with workspaces located above.
A gridded façade differentiates the project from other glass towers and blurs the line between hospitality and commercial, while the two-story block segments, varied in scale and alignment, emphasize the project’s staggered form. Landscaped terraces are integrated throughout the tower, elevating the natural connection to the park.
At the heart of the tower lies the Sky Lobby, situated over 100 feet above street level, offering panoramic views of Uptown and Downtown Dallas. This expansive space features a coffee bar, seating, and an outdoor terrace. Each floor employs a 100% outside air economizer with no air recirculation between floors, preventing cross-contamination. MERV 13 filters, often used by hospitals, remove airborne bacteria and allergens, while optional upgrades like ultraviolet or bipolar ionization systems provide additional protection.
On the Building Team:
Owner/Developer: Pacific Elm Properties
Architect: Kohn Pedersen Fox (KPF)
AOR: Corgan
Structural Eng: L.A. Fuess Partners
Civil Eng: Kimley Horn
MEP Eng: Telios Corporation
Landscape Architect: OJB Landscape Architect
General Contractor: Austin Commercial
Book Tower
Detroit, Mich.
Book Tower is a reimagined, adaptive reuse development that blends history and Italian Renaissance architecture with modern amenities. The 100-year-old, 38-story skyscraper had been completely vacant for years prior to Bedrock’s investment into the seven-year historic restoration.
Key rehabilitation efforts included restoring the original copper roof, terra cotta ornamentation, and limestone and masonry façade. Materials and design decisions focused on sustainability and energy efficiency, with a dedication to preserving original features of the building whenever possible. Ornate ceiling tiles were hand-painted in the original colors, and 50,000 sf of marble were reinstalled.
The restoration also included repairing 29 exterior caryatids, adapting former office spaces into 46 unique floor plans for apartments and hotel rooms, refitting the rooftop event space with a 2,200-sf skylight, repairing original travertine floors, and revealing the classic limestone façade. Restoring Book Tower, rather than developing something new on the site, reduced the carbon footprint by an estimated 85 percent.
Book Tower also includes 229 residential units to meet the need for increased housing needs in Detroit. It is also home to Detroit’s first ROOST Apartment Hotel, offering 117 extended stay suites with boutique hotel features.
On the Building Team:
Owner/Developer: Bedrock
Architects: ODA Architecture, Kraemer Design Group (Historic Preservation Architect)
Construction Manager: Brinker | Christman, A Joint Venture
Southline
Dorchester, Mass.
Southline is the repositioning of a three-story office and industrial building—the 16.6-acre former Boston Globe headquarters at 125 Morrissey Boulevard. The 700,000-sf retrofit is now a modern hub for creative office, laboratory, and retail uses.
It includes 360,000 sf of office space, 300,000 sf of flex/industrial space, retail, 100,000 sf of lab space, a 10,000-sf fitness center, 100-seat restaurant, and a micro craft brewery including an outdoor beer garden. 868 parking spaces and 200+ bike storage spaces are also available on-site. A multi-story atrium creates a central gathering area with food hall and collaborative meeting/gathering spaces. Southline aims to attract tenants who will stimulate growth in the fields of life science, high tech manufacturing, and technology.
The project's biggest challenge was that the 700,000-sf building is wedged between major highways, requiring the team to stretch the project budget and planning to create a sustainable and inviting community. Southline Boston has attained LEED Core and Shell Silver certification, with a significant portion of points derived from diverting over 90% of the building's structure and mass from waste streams. Improved site and connectivity including enhanced multi-modal paths linking neighborhoods and transit lines and stewardship of the neighboring parkland, Pattens Cove also contributed to certification.
Beacon remains committed to Southline’s Fitwel certification, supporting local businesses like Craft Food Hall, a budding restaurant concept offering healthy food, and Inner City Weightlifting, a fitness operator with a social justice and inclusion-based business supporting those reentering society.
Healthy indoor environmental quality is a high priority, with Real-Time IAQ monitoring showing Southline Boston's air pollutant levels in 2023 and 2024 being 17% and 45% lower, respectively, than typical commercial office buildings. Annual water sampling based on the Harvard research framework, the 9 Foundations, reveals Southline Boston scored nine points higher than the median Healthy Building Benchmark of over 1,000 buildings.
On the Building Team:
Owner/Developer: Nordblom Company, Beacon Capital Partners
Architect: Stantec
Structural Eng: McNamara | Salvia
Civil Eng: Howard Stein Hudson
MEP Eng: BR+A Consulting Engineers
Landscape Architect: Copley Wolff
General Contractor: John Moriarty + Associates