Redefining Market Street: Clemens Construction Leads the Way in Office-to-Residential Conversions

By Stephen Pouppirt, Clemens Construction Company

Across the Mid-Atlantic, developers are looking at aging office towers through a new lens: as opportunities to create much-needed residential housing. Conversions of this scale demand a builder with deep expertise in adaptive reuse, technical problem-solving, and collaborative project delivery. Clemens Construction has been meeting that challenge for years.

The recently completed transformation of 1701 Market Street—now reintroduced as 17 Market West—stands as a testament to Clemens’ leadership in this sector. Working with Alterra Property Group, Clemens successfully converted a 500,000 s/f, 18-story mid-century office building into a 299-unit luxury residential tower in the heart of Philadelphia’s Market West district.

Originally built in 1957, the structure was reimagined while retaining the character of its Indiana limestone façade. Larger operable windows were cut into the historic exterior, supported by hundreds of custom steel brackets—a technically demanding process executed with precision and safety at the forefront. Perforated copper-colored screening at the podium levels, vertical façade columns, and a striking rooftop sky frame elevated the building’s presence while signaling its new residential identity.

Inside, the building underwent a complete gut renovation. Floors six through eighteen now house thoughtfully designed one- and two-bedroom apartments featuring large closets, hybrid work nooks, and high-end finishes. Residents enjoy expansive city views and abundant natural light—benefits of floorplates that once posed a programming challenge but were reconfigured into a market-ready strength.

Amenities rival those of newly built luxury towers. The rooftop offers a saltwater infinity pool, cedar trellis seating areas, outdoor kitchen, and dog run. Indoor spaces include a fitness center, sauna, pickleball and basketball courts, golf simulator, and club room. The welcoming lobby features custom white oak millwork, limestone tile, and finely crafted details that echo the elegance of train travel.

Beyond finishes and amenities, the project’s success hinged on strategic construction management. Demolition began in January 2024, and by May 2025 leasing had already started—months ahead of substantial completion. By repurposing major systems such as elevator cores, stairwells, and the central cooling tower, Clemens cut at least a year from the construction timeline and saved millions compared to ground-up development.

This project also demonstrates Clemens’ commitment to sustainability. Reusing structural systems and materials reduced embodied carbon, while operable windows and modern MEP upgrades improve energy efficiency. Direct connection to Philadelphia’s transit concourse makes car-free living convenient, further reinforcing the project’s urban sustainability goals.

Complex projects like 17 Market West are never without challenges. Tight urban logistics, phased occupancy, and structural modifications required careful coordination across trades. Clemens deployed swing scaffolds, construction hoists, BIM modeling, and detailed sequencing to keep the project on schedule and safe. Weekly planning sessions and close collaboration with Alterra, the design team, and trade partners ensured alignment from start to finish.

For Clemens Construction, the success of 17 Market West is part of a broader story. As office-to-residential conversions become a defining trend in urban real estate, Clemens’ unique experience—built over decades of complex renovations and adaptive reuse—makes the firm an ideal partner for developers seeking to unlock value in underutilized office assets.

From historic façade modifications to modern amenity integration, Clemens has proven its ability to turn vision into reality. For developers considering conversions in Philadelphia and across the Mid-Atlantic, the message is clear: Clemens Construction is ready to deliver.

Stephen Pouppirt is president of Clemens Construction Co. in Philadelphia, PA.