"The design must already take deconstruction into account"

Empa expert Enrico Marchesi: "Our villages and cities are a huge warehouse. That's where we have to get our future resources." Photo: R. Strässle

The practice-oriented tinkering room Nest, a modular research and innovation building operated by Empa and Eawag in Dübendorf, put the new Sprint unit into operation a few weeks ago. As in the other living and working platforms of the innovation building, new technologies, materials and systems are tested and further developed under real conditions. Under real conditions means that flesh-and-blood people live in the units for a while. This is the only way the research team and the companies present with their innovations can find out how practical a particular application is.

How the circular economy works is already shown by the Unit Urban Mining & Recycling, Umar for short. It demonstrates how responsible use of natural resources can be combined with appealing architecture. According to those responsible, this unit is based on the thesis that all the resources needed to produce a building must be fully reusable, recyclable or compostable. This is a major challenge for the construction industry and its suppliers, most of whom are still miles away from the idea of recycling.

At the Unit Sprint The Innovation Building is an office landscape. It lives exclusively from deconstruction, i.e. the reuse of materials and components. "The stock of reusable materials as well as the re-use potential in industry are large and just need to be exploited," emphasizes Enrico Marchesi from Empa. He tells what's what during an on-site visit.

In the Sprint office unit, the concept is called Re-Use. The wall on the right, for example, is made of old carpet tiles. Photo: Martin Zeller

The Nest Sprint unit wants to set new standards for circular construction. For the Re-Use principle to work in everyday life, construction experts have to turn conventional planning on its head.

Enrico Marchesi, Innovation Manager Nest, Empa: Planning is a key word in connection with re-use. If you want to use materials or components that have already been installed once, you have to start reuse planning early in the project, because this has an impact on design and materialization. One example: We knew in advance that we would receive enough aluminum windows from a high-rise building in Zurich Altstetten for the Unit Sprint. Based on these reusable windows, the architect's office adjusted the façade designs accordingly. In other words, builders, planners and architects have to rethink what they are looking for in a re-use building. The question of available materials and components from deconstructions are in the foreground. The rest must be coordinated with this.

The online platform Madaster works with a material passport that shows which components and products were used in a building. Is this the solution for circular construction?

Yes, and not only for buildings like the Unit Sprint, but worldwide. As we know, the concept of the urban mine exists. Our villages and cities are a huge warehouse. That's where we have to take our future resources from - and we have to do it every time we deconstruct. Madaster, a cadastre for materials or something like an online land register, manages this store of materials with its inestimable value.

All well and good, but not everyone enjoys floor and wall tiles from the 1950s or 60s. Aren't design and color a big obstacle to the idea of reuse?

Admittedly, it takes flexibility in the design. The planner must be aware that the found or existing material partly determines the final design. But this can also result in very exciting solutions, as our Sprint office unit shows. It is true that the windows, the ceiling and the solid wood parquet show that they have been used. We deliberately left the floor as it was - it could also have been refurbished, in which case it would look like new.

As I said, for our residential and office units Urban Mining & Recycling and Sprint, we used exclusively recycled materials or reused components. However, this does not mean that one hundred percent of a conventional building has to be constructed in the same way. It is already a great help if only part of the building consists of recycled and reused components.

Their concept calls for better deconstruction of buildings.

That is definitely the case. From a technical point of view, every building of today could be disassembled according to type. Economically, of course, this is not possible because the principle of "design for disassembly" has not been applied. This means a design that already takes deconstruction into account. What's more, what's needed is a design that facilitates future modifications and disassembly for the recovery of systems, components and materials. This can ensure that buildings and their components can be transferred to another cycle as efficiently as possible at the end of their service life. Future buildings must be constructed according to this principle.

Which materials and components can or should not be reused?

If the building materials of a deconstruction are contaminated with hazardous substances, they belong to the disposal. Otherwise, all components can be reused: Either you prepare them so that they can be reused in their previous form or you feed them into the recycling process. I am talking about recycling and not downcycling, which is unfortunately still often the case today; the secondary raw material must therefore not be of inferior quality. In this respect, the industry has not yet done its homework and must hurry up if it still wants to survive on the market in the future.

Such a change in thinking also brings with it new business models. Carpets, for example, always have an expiration date. There are already companies that have developed recyclable carpets. What's more, the customer can only lease them. We have such a carpet in the Umar unit. After the expiration date, the company wants the raw material back. This is a smart idea.

Technical applications usually become obsolete quickly. What about the re-use principle here?

This has to be looked at individually. It may be that a product is so outdated that it falls out of the grid. For example, we had a used ventilation system retrofitted for Sprint - it was given a second life. Even with technical equipment, I have to appeal to the industry to design their products in such a way that they can be sensibly disassembled. As I said, in the longer term the scarcity of resources will force us to do this.

At the moment, building material is difficult to supply. You didn't have that problem with Sprint.

...only sometimes we had to search a little longer until we found the right old material. But you're right: we wanted to install a heating and cooling ceiling, for example. If we had wanted a new one, we wouldn't have been able to get one within a reasonable period of time, because the market has completely dried up. In Sprint's case, we found a used acoustic ceiling that the supplier upgraded to a heating and cooling ceiling. A nice example of an upgrade.

The Urban Mining & Recycling residential unit shows that secondary raw materials can be turned into aesthetically pleasing products. © Zooey Braun-Stuttgarts

Which building materials do you see the greatest potential for reuse?

Pure re-use of building materials can only cover a certain part of the market. But in urban mining and recycling, I see interesting opportunities for the industry. A wide variety of products can be made from secondary raw materials. Reuse could become interesting in the area of old floors, windows or materials that have a visual and tactile quality. I also see a demand for construction wood that is not weathered.

The re-use principle is changing the value chain.

Sure, for example, there will be a shift back - craftsmanship is suddenly in demand again. When re-use materials are used again, craftsmanship is increasingly needed. What does the CO2 and energy balance look like when building after re-use? The exact life cycle analysis of Sprint is currently being done, I can't give you exact data yet. But just this much: the environmental balance is definitely better when using used building materials than with conventional construction, because new production, which requires a lot of energy, is eliminated, as you know. The CO2 balance does not necessarily look better when used components are transported halfway around the world. So they should come from regional sources if possible.

A building like the Sprint Unit should actually be less expensive.

The construction costs for the material portion are basically reduced with the re-use principle. However, the effort required to find and prepare secondary components does not come free of charge, especially in a country like Switzerland with high labor costs. That is the current state of affairs. But the young industry has not yet been optimized. That will come sooner or later, after all, our resources are becoming increasingly scarce, ergo also more expensive. That's why there's no way around the circular economy, whether in the form of the re-use principle or clean recycling.

Re-use material tested for building acoustics

Researchers at Empa tested the carpet partition specially designed for Sprint (see picture above) for airborne sound insulation in the acoustics laboratory. Several measurements were taken to investigate how the carpet tiles must be folded for optimum sound insulation. In the best case, the researchers achieved a sound insulation of 26 decibels, as Empa writes. This means that the carpet wall as a room divider achieves significantly better acoustic insulation than, for example, mobile movable walls in group offices. According to Empa, the result shows that the circular partition wall has potential wherever buildings are designed to be flexible or even temporary, such as in modern interim uses.

www.empa.ch/web/nest

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The contribution "The design must already take deconstruction into account" first appeared on Environment perspectives.