A groundbreaking renovation project in Copenhagen has turned a 1960s factory into a thriving community arts hub while achieving an impressive 95 percent material reuse rate. Pihlmann Architects, led by Søren Pihlmann, won a competition by the Bikuben Foundation to transform the old factory at Thoravej 29 in northwest Copenhagen into a space dedicated to supporting young artists and creative organizations.

The innovative approach involved using the building's own waste materials as primary construction resources. When the renovation required creating double and triple-height spaces by removing concrete floors, Pihlmann Architects chose to "flip" these floors rather than dispose of them, transforming them into concrete staircases throughout the five-story building. "None of the concrete has been thrown out; it's just been utilized for various purposes," Pihlmann explained during a tour of the building at the Copenhagen Architecture Biennial opening.

The 6,224-square-meter building now houses studio and production spaces for young artists, along with workshops, a library, exhibition rooms, and offices for numerous organizations. The ground floor features a public cafe, while communal rest areas on higher floors provide gathering spaces for the building's 35 tenants, ranging from individual artists to larger organizations. The design philosophy emphasized accessibility on the ground floor while becoming more tailored to specific users on upper levels.

Pihlmann's commitment to waste reduction extended beyond concrete reuse. The team salvaged wooden materials, including old doors, and partnered with a supplier in Jutland, Denmark, to shred the wood waste into particles for creating new particle boards. "Most of the furniture that you see in the house actually derives from the waste material from the building itself that has just been shredded and formed into new particle boards," the architect noted.

The building's exterior renovation also embraced the reuse philosophy. While portions of the original yellow-brick facade were preserved, other sections were repurposed to create brick pavements surrounding the building. "When you enter the building, you're walking on a yellow brick pavement," Pihlmann explained. "It is actually the lower wall partitions that used to be underneath the windows that have been cut out and flipped down to form this brick pavement."

Structural modifications included extending the facade by 1.5 meters, which Pihlmann described as offering "a very flexible way in which this building, over time, can adapt to different uses, and it also became a way to energy-optimize the existing facade." This approach ensures the building can evolve with changing needs while maintaining energy efficiency.

The project's environmental impact has been significant, with the team reporting CO2 emissions reduced by up to 88 percent compared to new construction. This achievement stems from the radical approach to material reuse, with leftover concrete also fashioned into furniture pieces scattered throughout the building, including seating areas in the public spaces and work areas.

For Pihlmann, this project represents a fundamental shift in how renovation projects should approach existing materials. "Of course, at some point you'll end up introducing new things, but I think you need to revisit the existing to such a degree that you're fully aware that when you introduce new stuff, it's because there's a reason for it," he concluded. The architect advocates for making material reuse the starting point for any renovation project rather than an afterthought.

The Thoravej 29 project was featured prominently during the Copenhagen Architecture Biennial, which runs from September 18 to October 19, 2025. The biennial showcased numerous innovative approaches to sustainable architecture and adaptive reuse, with Thoravej 29 serving as a prime example of how creative thinking can transform construction waste into functional design elements while supporting the local arts community.