Daniel Marshall founded Re-Assembly in 2022 to investigate the potential to recycle architectural glass. Questioning the premise that its end of life should be waste or downcycling, he has combined computational matching with professional experience as a facade engineer to work on the development of a shingle system made entirely of recycled architectural glass. Marshall spoke with Chris Walton about the state of facade deinstallation, his current work at Re-Assembly, and the potentials of recycling at a scale that meets architecture’s massive amount of material consumption.
Chris Walton: How did you become interested in glass recycling?
Daniel Marshall: Professionally, I’ve been working with glass as a facade engineer for the past four years. Prior to this, my thesis and academic research focused on architectural glass reuse and reducing the embodied carbon of the construction sector. I calculated that if New York arranged all the shattered glass from demolished buildings since 1955, the city could make a glass canopy approximately 6 kilometers square. Through Re-Assembly, I’m trying to leverage my professional experience toward the reuse agenda.
What is the state of glass recycling in practice as it stands now?
It’s nonexistent. No U.S.-based float glass plant uses any postconsumer recycled glass in their production lines. Instead, most postconsumer float glass is downcycled into glass bottles. Why can’t the glass industry fix this? The problem is nickel sulfide inclusions—impurities in the glass, which grow and can crack tempered glass. The fear of impurities means the U.S. glass industry refuses to accept any postconsumer recycled content.
How have you explored alternative life cycles for glass used in architectural work?
Insulated-glazing shops in the U.K. and U.S. typically have a storage rack of mismeasured units which are costly for them to dispose of. Re-Assembly gathers these brand-new, warrantied glazing units into a library. Once we have this inventory of mismeasured units, we match them using some computational tools. We take the design intent and the library of material and put those two together, tweaking the design in response.
The stage you’re at now is taking offcuts from manufacturers that are not being used or sold, but the hope ultimately is for a demolition or renovation process where IGUs are taken off a building, and put into your system?
Yes. There are ways you can authenticate IGUs. One of the pathways I can see happening over the next five to ten years is creating standards for verifying material that is functional. Number one, check that argon has not leaked out. Number two, check there’s no microcracking. Contemporary glass procurement relies on standards and tests to assure quality. I see no reason why reused glass with the right certifications could not be acceptable to architects and their clients.
You’re using a Grasshopper script that reads a given elevation and tries to match the library to it as best as possible?
Exactly. If you have a fixed rough opening and a limited library, you may not be able to build that wall perfectly. Working out how big a library must be is a question I’ve been working on recently: Currently, I think you need about 100 pieces of glass with some variety. The script is pretty simple: It’s just adding up glass widths. Part of this simplicity is thanks to the shingle idea. You have freedom on one axis to overlap, so you don’t have to absolutely nail all your dimensions.
In contrast to the pristinely detailed curtain wall, which you will never make perfect.
Yes. My current mock-ups are rather improvised and experimental! I’ve been running air and water tests where you suck air through the facade—putting a vacuum on the interior side. Then you spray the glass on the front and see if any water gets through your facade system. I’m also running structural deflection tests. When you shingle something, you’ve got some pretty weird deflections and can end up pinching the glass. You don’t want to get into a situation where it deflects and breaks the glass. These tests all represent the typical performance criteria for U.S. curtain walls; the system must comply with all those standard requirements.
Many cities have stringent regulations on operational energy standards. How does your system perform operationally?
I’ve been doing a lot of thermal analysis because of what you’re saying. Glass is really conductive, so you need thermal breaks between the glass on the interior and the glass on the exterior. The overlapping shingle becomes four layers of glass. This quad cavity keeps the performance comparable to off-the-shelf systems.
When you’re removing an IGU from a building, is the rest of the system going to last as long as the glass itself? Is glass the only concern in terms of verification?
You’re raising a good question. If you’re taking apart a whole building, there are a bunch of other things that come with the glass: aluminum window frames, mullions, shade boxes, etc. For me, it feels more realistic to take each element apart, authenticate, and then recombine them into a new assembly designed for a specific project. But perhaps the option where we just remove an assembly from one location and use it in another will prove more practical.
If you had to replace an IGU, does that allow you more flexibility to go into the library and find a piece that matches, or is that more difficult because you have to find the same glass product to put back into the system?
On a traditional building site, if a piece of glass breaks, you might be able to take one from your attic stock and keep going. In the specifics of this system, you can rerun the algorithms again and reallocate the pieces, or just buy a replacement. Rerunning the matching becomes difficult from a permitting perspective. Architectural drawings that you give to the city might change, and your energy filing elevations might vary slightly. Perhaps it is possible to note “placeholder elevation drawing for the Re-Assembly recycled facade system.”
Where do you want to take this?
I plan to do more final testing and mock-ups. The main intent is to get architects to talk about glass, its embodied carbon, and the fact that we can’t recycle architectural glass. I’d like to try to use this system in a real-world project to show it can work, offering a precedent that can stimulate architects’ imaginations about resource responsibility.
Chris Walton is a master of architecture candidate at Harvard GSD and a former assistant editor at AN.
