Circularity is no longer a trend

The interior and construction sector is facing a fundamental shift. While sustainability was long viewed as an ambition or a differentiator, it is increasingly becoming a prerequisite. Clients are demanding insight into the origin and environmental impact of materials, regulations are moving toward greater transparency, and raw materials are under increasing pressure. Consequently, the question is no longer whether the sector will change, but how we will shape that change in practice.

For years, the standard was relatively simple: when an interior no longer met requirements, it was replaced. Existing furniture, materials, and finishes made way for new products. We now know that this is precisely where a significant part of the challenge lies. A product may be aesthetically outdated while still being technically viable for years to come. A cabinet may lose its original function, yet the materials it is made of still represent value. To work circularly, we must learn to look differently: not just at what we have, but first at what is already there.

"The circular economy is not about lower quality, but about using raw materials more intelligently," says director Karst Wouda. "Circularity is not a passing trend. It is becoming a permanent part of how we design, build, and furnish."

Circularity is still frequently linked to recycling or choosing a material with a sustainability label. But that means the discussion is starting too late. The R-ladder makes this clear. Recycling is relatively low on this ladder. Strategies such as Refuse, Reduce, Re-use, and Refurbish rank higher because they preserve more of a product or material's original value. Therefore, the first question should not be: what sustainable material are we going to use? But rather: do we need to produce anything new at all?

This changes the way an interior project begins. Before a new design is created, an inventory can be made of what is already present. Which furniture can be reused as-is? Which parts can be refurbished? Which materials can be repurposed? Only when reuse is not possible or practical does the choice of new materials come into play.

From reuse to demonstrable impact

At the same time, the R-ladder is not a simple calculation where higher automatically means better. The actual environmental impact depends on the application and the entire life cycle. Transporting a material over a long distance to reuse it, for example, may have different consequences than producing a new local alternative. Circular choices must therefore not only sound good but also be demonstrably substantiated. Reliable information about materials, origin, and environmental impact is becoming increasingly important for this.

Transparency is thus becoming a key development within the sector. Knowing that a material is "sustainable" is no longer enough. We need to know where it comes from, what it consists of, how it was produced, how long it lasts, and what can be done with it when its current function ends.

Material passports are playing an increasingly important role in this. Such a passport records, among other things, which materials have been used in a piece of furniture or interior, in what quantities, and how components are connected. This creates, as it were, an ingredient list for the interior. That may sound administrative, but this information can ultimately determine whether circularity is actually possible in ten or twenty years. After all, a future project team can only reuse materials effectively if it is known what is present and how it can be disassembled.

However, a material passport does not automatically tell you how sustainable a product is. Other tools are needed for that. An Environmental Product Declaration (EPD), for example, provides insight into a product's environmental impact based on a life cycle assessment, from raw material extraction and production to use and end-of-life processing.

"The next step is that we don't just say that a solution is more sustainable, but can also explain why," says Ward Huting, responsible for sustainability and innovation at Zwartwoud. "Where people used to look primarily at price, functionality, and appearance, clients increasingly want to know the impact behind a material or product. You need reliable information for that."

The combination of different types of data is becoming particularly important. A material passport tells you what is in a product and what is possible with it in the future. An EPD or LCA provides insight into the environmental burden. Together, they ensure that choices can be made not just based on ambition, but increasingly on measurable information. This also changes the meaning of an interior: a table, wall, or cabinet is not just a finished product, but can be seen as a temporary assembly of raw materials and components that can become available again later.

Designing for what comes next

That information only has real value when a subsequent life cycle is taken into account during the design phase. A piece of furniture that is fully glued together may consist of valuable materials on paper, while those materials are barely separable at the end of its life. That is why principles like demountable and modular design are becoming increasingly important. Screw and click connections can replace glue, parts can be made individually replaceable, and products can be designed to adapt to a different function later. The decisions made at the drawing board today largely determine what possibilities a product will still have in ten or twenty years.

This also requires a different type of collaboration in the chain. The architect can formulate a circular ambition but needs information from producers and suppliers to substantiate material choices. The producer can design for disassembly but needs to know how a client wants to use a space in the future. And a material passport has little value if information is not properly recorded during the process or is lost later. Circularity is therefore not the responsibility of one discipline, but a collective task.

In the coming years, we expect the boundary between designing, producing, managing, and reusing to blur further. Information about materials will need to remain available throughout their lifespan, and design choices will increasingly be assessed based on what they mean for a subsequent phase of use. For interior construction, this means a significant shift. We are not only responsible for what we deliver today, but must increasingly think about what can be done with it afterward.

That is why Zwartwoud views knowledge sharing as a vital component of the circular transition. Not because one organization has all the answers, but precisely because the necessary expertise is spread across the entire chain: among clients, architects, manufacturers, suppliers, educational institutions, and government bodies. Many of the techniques required for circular operations already exist. We can inventory materials, refurbish furniture, design products for disassembly, calculate environmental impact, and document material information. The challenge for the coming years is to increasingly approach these individual elements as a single, integrated system.

Ultimately, circularity is not about finding one perfect material or a single technical innovation that solves every problem. It requires a fundamentally different way of looking at value. The focus is not just on the cost of creating something new, but also on the value that already exists, how long we can preserve it, and what we must do today to ensure that value can be reused tomorrow.

That, in our view, is the future of interior construction.