Advancing Circularity through Glass Reuse

Above: Façade restoration of Herostrasse 5, Zürich-Altstetten by Lüchinger Meyer Partner AG.

Many in the glass industry are looking for sustainable solutions in order to maximize the energy-efficiency of facades while reducing the global warming potential of building materials. Over the past few years, a team of Dow professionals and building researchers have explored ways to realize circularity by remanufacturing glass systems from materials reused from the existing built environment.

Researchers from Dow subsidiaries, as well as the Switzerland-based façade engineering organization Lüchinger Meyer Partner (LMP), demonstrated how carbon-neutral silicones can be used to extend the life of post-installation building materials by reusing them on the façade. Their work has been published in two papers, “Silicones—An Important Enabler of Sustainable Design,” first published for presentation at the 2023 Glass Performance Days, and “Circularity in Construction: Scaling Up Glass Reuse with Silicone,” presented at the 2025 conference in June.

Circularity through reuse of materials

Working in Switzerland, researchers underscore the importance of reducing the global warming potential of building systems and minimizing the use of raw materials to meet sustainability targets. 

While Switzerland already recycles over 6,700 tons of recovered flat glass per year, the researchers argue that global warming potential can be even further reduced on an industrial scale through the reuse of glass systems that are uninstalled and then remanufactured into high-performance systems. While post-installation glass can be “downcycled” into products like foam-glass for applications like road fill, they claim another option is possible; taking older, installed glass from the existing built environment, remanufacturing the glazing system with silicone, and reusing the system as a building material.

Given the potential to reuse existing building components, the researchers refer to the existing built environment as an “urban mine” that can be used to “establish simple and efficient reuse processes to create sustainable façades and [help businesses] secure a prosperous future.”

The Herostrasse: a case study in remanufacturing

The team demonstrated this type of remanufacturing by reusing glass façade materials from the Herostrasse, a 1970s vocational college located in Zurich, Switzerland. As part of a building refurbishment initiated by the city, the research team put forward a reuse concept transforming existing glass panes on the façade into higher-performing cladding elements for the same building.

Given the age of the building, the existing glass panels lacked modern-day impact performance and post-failure resistance. Because of this, the researchers determined that the panels would have to be remanufactured and modified before they could be reinstalled. Post lamination was rejected, in part because adding a new pane of glass would increase the global warming potential of the system. Instead, the team bonded the glass panels to an aluminum mesh back sheet using carbon-neutral silicone from Dow.

After uninstalling the glass panes and cleaning them thoroughly, the team tested their concept on samples, and later the full-scale glass panes, which were tested for both impact-resistance and fire-resistance. Ultimately, the remanufactured panels were reinstalled on the façade as opaque spandrel glass.

Speaking in an interview with Glass Magazine, researcher Enrico Cutri, member of the Building Science Team at Dow, said that beyond ensuring high-performance, embracing this type of building component reuse may require the design community and building owners to accept an aesthetic that looks less perfect than a brand-new building, with brand-new products. “Going into a ‘Reuse Age’ we should lower our expectations about the perfection of aesthetics,” he says. “We should embrace a new building with fantastic performance that doesn’t look 100% perfect. I hope that’s the new way of thinking in architecture.”

Using AI to map and “mine” the urban environment

While researchers identified ways to expand upon their research, they also emphasized that next steps should include mapping out the built environment to find what materials are ready to be replaced and/or reused. That would mean using visual data of a city and analyzing it with artificial intelligence technology to determine which buildings need renovation, when the renovation could happen and what materials would be made available during reuse, researchers say.