Interview with Arjan Dingsté, Director / Senior Architect at UNStudio

As part of this month's focus on sustainability, we sat down with Arjan Dingsté to talk about the challenges involved in taking a holistic approach to sustainability.

What is the role or the scope of architects when it comes to sustainable design?

In the design process, our role differs to that of other stakeholders, in that we have to bring all of their expertise together and combine it into a holistic, integrated design.

Sustainability involves a very broad range of different expertises and most of those are also constantly evolving. It touches upon numerous technical disciplines, from structure to building climate and building physics. All of this means that our role as architects is constantly expanding.

We have also recently witnessed a change of focus from energy preservation - as driven by certification systems such as BREEAM - towards a focus on health. For instance, with the WELL Building standard. But as designers, we also have to look at social sustainability: how do people interact in the cities and buildings that we design and how can we encourage such interaction? In addition, we have to consider circularity; the life cycle of materials over the building’s lifespan and beyond.

What are we doing at UNStudio to bring that knowledge into the studio and to manage it?

We have always been very involved with research and extensive design analyses at UNStudio. As a result, we understand that we need to possess a lot of technical expertise in order to be able to address these kind of topics very early on in the design process. We have always used technology for this and have also had to adapt new technologies, new software and project specific parametric design techniques that we introduce very early on in the design process. The advantage of this is that we can always do our own analysis, from lighting, to wind, to radiant heating analysis. In the end, it becomes a case of form follows energy, form follows health. We don’t just use the results of this analysis to test if a design is sufficiently meeting targets, we use this input in the actual design, by really allowing the design to be influenced by these parameters and learning what that means. At times we also have to think a bit more like engineers than architects, in order to be able to communicate ideas clearly with the engineers and make integrated design proposals.

UNStudio has an in-house group that specialises in sustainability. What does it do? What are its goals?

We call the group ‘sustainability engineering’ and I think that frames it quite well. It looks into how we can develop useful tools and processes in-house. Because sustainability is a design thinking process, as much as an engineering parametric approach. In the past, we focused a lot on parametric design in the sense of form generation and form rationalisation towards production. Now, we are using these techniques more and more to optimise our buildings. That means we are really driving optimisation from an holistic perspective.

We have a very gifted associate director, Marc Hoppermann, who was the first architect in the Netherlands to get the WELL Building certificate. Marc has a great deal of technical knowledge, while he also comes from a parametric background. So as a practice we are bringing together the knowledge these experienced people have on these topics, with the goal of developing the right tools to help us in the design process.

In the end it’s an iterative process that needs a holistic view, but it also needs in-depth knowledge of how buildings actually work. So the goal of the sustainability engineering group is first of all to educate and inform our younger architects, but also to bring their fresh thinking into the process and develop with them the tools that we need to make our design processes, our buildings and our cities a lot smarter.

In your opinion, what currently needs to be improved in how we design for sustainability?

I think one of the key areas in which we are actively trying to gain more knowledge is the life cycle of  structural materials (woods, concrete, steel etc.) and the choices that we typically make concerning this very early on in the design process. What we have seen in the past is that often these choices are made out of habit, or sometimes even from an emotional standpoint, but it’s important that such choices are rational and informed. In some instances, a steel building would actually be a more sustainable choice for a certain typology, than would a timber construction. This is something we believe to be essential in our decision-making and design thinking processes. We need to come back to these questions in every choice we make and take rational decisions when measuring the life cycle of the materials we use, because the truly most sustainable option may not be the emotional choice, or a trending material. We currently need to gain more knowledge and develop better toolsets to assess this. But while you have to take an analytical or scientific approach to materials initially, in the end skilled designers will always find ways to make it look good and make it work on multiple levels.

Both sustainability and design are extremely important to clients. They want a sustainable building, but they also need a beautiful and well-designed building that people will want to live, work in or visit. So what influence do clients have on these processes?

It really depends on the typology of a project. Over the years, it has become apparent that the BREEAM system can certainly be used to benefit the marketing of a building. The problem with this is that it can lead to a sort of ‘Excel sheet Sustainability’, rather than let's say, an idealistic balance of what would make the most healthy, or sustainable, or energy balanced building.

At UNStudio we have done a great deal of research from a perspective of health and wellbeing. So finding a balance between sustainable concerns and user health is often a focus in our discussions with our clients. It’s actually one of the first questions we typically ask our clients if they talk about sustainability. What does that in fact mean to you? Are you talking about receiving a BREEAM certification to put on the window of the building? Is there an idealistic kind of corporate governance structure in your company that demands energy positive buildings? Or is there an intrinsic personal drive behind this focus? This is where our clients are particularly important as dialogue partners. Once we understand where they are coming from, we can forge a path of discovery together with them, based on our expertise and with help of the consultants we work with. We make our best projects when this path can be taken.

What are the shortfalls of current certification systems such as BREEAM and even the Well Building standard?

We would prefer to design by using these tools, or systems, more as guidelines that help us to address the right topics. Then we, and our clients, would be able to see what particular things are important for a specific building. And we would be able to identify what's important for the specific users of the building. The answers to these questions might drive completely different design decisions than those laid out by the existing certification system. Then you are left with either aiming for what’s best for the project versus getting the most points with the lowest investment. These are the challenges that I see with these systems. Sometimes they influence you to make irrational choices, or not the right choices; choices that go against healthy thinking in buildings.

Designing against set regulations is fine, but far too often architects do it as an exercise at the end of a project, to see if their design complies with these systems. But you would reach intrinsically different results if you would start with this thinking right at the beginning of the design. This is where an important mind shift really needs to happen right now and it’s what we are trying to change here at UNStudio. This approach is really where we need to move to as an industry.

Is that one of your drives with the ‘sustainability engineering group’? Not just to expand knowledge, but to change the way we approach the design process?

With the sustainability group we are testing external tools, but we are also developing internal tools that can drive these processes. We will and are educating our colleagues to be aware that the choices they make from the first sketch are going to define the end result and the final performance of these buildings. It isn’t just about orientation, or the shape of the building, it is in the choices we make from the moment we begin designing these buildings. This thinking has to start intrinsically at the beginning of the design process.

When it comes to sustainability, different typologies and different scales bring with them their own individual issues. What kinds of things should people be thinking about these differences? Can you give some examples?

I think a very concrete example is if you look at the performance of different material choices for the basic structure of a building. We are currently seeing very positive developments in the use of wood as a construction material, because it’s renewable and has locked in CO2 and therefore a very good score in certification systems. But actually, you really have to consider the typology of the building first. For example, an office building has a completely different grid dimension than, for example, a residential building. Grids that are optimal for the spans between the columns in offices, are actually uneconomical, or inefficient for pure timber constructions. And while we find timber constructions to be suitable for residential buildings, they also pose acoustic challenges. This then means that you have to add further materials on top of the wood to make it work and as such expand on the material footprint again, so it’s a complex exercise: what is then the embodied CO2 level of those materials? And what is their life-cycle assessment? This means that for many projects we need to look into a combination of materials to find the most balanced and workable solution. This, however, requires a more complicated design and engineering process than just picking a single material.

Another issue is the challenge of figuring out how to best utilise the relatively small surface area on the roof of a tall building. What are the possible solutions to that problem?

The ‘battle for the roof’ happens in a lot of our projects. We grapple with whether it should be covered in PV panels, for energy generation - because if you have a lot of roof surface, you can of course generate more energy for the building. However, if you approach it from a more holistic angle, you start to assess what the embodied CO2 is in these PV panels and that may then affect your decision-making.

When you’re dealing with high rise buildings, it gets more complex. Typically, you have a lot more facade area than roof area, and here the roof can also be used to add green, retain water and support biodiversity. So you also have to take the human experience into consideration, and consider the health benefits of roof terraces as recreational areas. Here we also see an opportunity to combine programmes, either within the building or within cities, to make smaller energy networks.

The taller the building gets, the more holistic the approach has to become. But then solutions become more elusive. We have been able to solve this conundrum for some of our high-rise projects, which has brought about some a very interesting innovation.

At UNStudio we have also been trying to develop real solutions. One of which is an aesthetic photovoltaic panel for use on facades (‘Solar Visuals’) that really can visually blend into the building, while freeing up the roof surface for other uses. We were part of an initial research consortium, but the product has since been developed by UNSense, TS Visuals and TNO and is now on the market. It has already been used on a number of new buildings, including the Tours Duo building in Paris by Jean Nouvel.

Finding ways to store energy is also a challenge we are currently facing. What is currently being done to solve this?

This is actually the greatest challenge we are currently facing, as we make the switch to electric energy. We need to be able to store this energy, but we already know that the footprint of just a car battery is too high.

In the Netherlands we use geothermal energy very intensively within our buildings, to the point where buildings are competing with each other to get their hands on that little bit of available space under the ground. So geothermal energy has its limitations. Another issue is that wind and solar energy are weather-dependent, and therefore don’t always match the demand in terms of timing, and storage of this power in current battery solutions is very limited. But there are some interesting developments taking place.

One is that, with PV and wind you could also produce hydrogen, which can be stored in tanks. But hydrogen is highly explosive, so there are risks with that also. But at least it's one possible way of transforming electric energy into a storable energy format. Already 10 years ago, we conducted research into using small hydrogen energy sources in buildings. Test cases are still happening in neighborhoods in the Netherlands, but to actually be able to generate hydrogen on the spot, by electric means like PVZ or wind, that would be really interesting!

We are also seeing developments in phase change materials, and while storing energy within the mass of buildings is already a technique that has been used for a long time, it's not controllable on demand. PCM tanks are another example, where we can basically change the state of the material or store energy. But all of this is still on an experimental level and needs to be developed much further before it can actually be considered a go-to solution.

Ideally we would like to decentralise this energy storage as much as possible, and where possible create self-sufficient buildings. But for now, we will have to be a bit more patient and continue to follow these developments carefully.

Wood seems to have become the go-to (and somewhat hyped) material in recent years, but at times a hybrid solution might be better. Could you explain why that is?

It’s true. It almost feels like if you are not designing your building in wood, you are doing something wrong, or bad for the environment. But that in fact means that the choice of wood is an emotional one. Wood does of course have great advantages. It's a renewable product and it locks in CO2. But while it’s a good material, that doesn't automatically mean it's the best solution for a specific project in a specific location. This is why I would advocate for a more analytical approach to these material choices; to establishing a procedure for checking which systems give the right solutions and have the smallest footprint in each case. Lifecycle assessment (LCA) methodologies are an example of that. They allow us to check if the choice of a specific material is really functional, or how much would be used. Or, if a combination of two materials would be better, such as steel and wood, or steel and concrete.

My standard approach would be to limit material used to an absolute minimum, but that always has to be balanced with functionality, because the functionality will determine the life span of the building. The most flexible and adaptable buildings are the ones that will still be there in a hundred year’s time; those in which the various material layers (from the fit out, to the facade) can be renewed when necessary and those designed with flexible structural systems that enable repurposing without alteration. This is actually the highest level of sustainability that you can achieve, so we have to make rational choices with every one of these layers.

This means that if you design the structure with future flexibility and adaptability in mind, you may initially need to add more materials or make a different, more resilient choice in the design. However, for the fit-out you could choose more bio-based materials, because they can be renewed at regular intervals over the building’s lifespan. In the end, what is required is a holistic approach, but also a very analytical one.

Even if your building is designed so well that it lasts a very long time, at a certain point it will probably need to be dismantled and you have to consider that also, which presumably will also affect your choices?

Yes, it does. We now have to look beyond the energy used in production, and beyond recycling, towards designing for the re-use of material components. So how we attach these components also has to be a consideration, because they have to be dismantled without damage. This also means you have to design elements with dimensions that are suitable for re-use. You can design a small floor to be detachable, but if it's a two-metre-long floor, how can you use that again in another building? However, if it's a long span element, you can simply cut a piece off and fit that into the next project. It is this kind of thinking that is increasingly being built into the methodologies that are being provided by, for example, Green Building Councils. But basically, if we connect the detachability of components to lifecycle analysis thinking, then I think we're heading in the right direction regarding how to design our buildings.

We mentioned that wood is everywhere these days, but is progress also being made in making  concrete more sustainable?

There are several developments there, because cement is one of the most polluting elements in construction. But there are different ways to reduce the amount of cement in concrete, or to remove it completely. There are now technologies that can break concrete down into its original components of stone, sand and cement, but that’s quite an intensive process that also uses a lot of energy.

There has also been a shift in recent years towards producing concrete that uses polymer binding elements, instead of cements. We already had polyester concrete in the 1960s and this is a kind  redevelopment of that, that can also use more bio-based binding elements. But that is in the first stages of testing right now. It does however mean that by using these new kinds of components, we can make concrete a more sustainable material. And this also again goes back to the question of how we can take things apart or best use them as re-usable components.

A lot of re-thinking and a lot of experimentation is still needed in this is part of the construction industry, but there are definitely ways to improve concrete and make it a more balanced and sustainable choice compared to other materials.

You talked about how you have to make buildings both energy efficient and healthy for people. But then you also have the question of aesthetics. Where does that fit into the sustainable design equation?

Well, of course there is not an all-embracing answer to that, but we know that design is essential to how people experience and enjoy buildings; the balance within design and the way spaces interact with the user on a psychological level are very important.

I typically don’t see the design components, the aesthetic part, as so much of a problem, but more as something that is derived from the process. What we see with these kind of analytical approaches - even if we start by working with algorithms to test different options - are very surprisingly solutions that we would not have predicted or rationally come up with otherwise. It's quite intriguing to turn these kinds of unexpected results into designs we would have never thought of, but that are then still very rational in performance. Geometry in architecture can become much more interesting this way. Making buildings look good is in the basic skill set of architects, but it becomes much more interesting to me if something unexpected results from a kind process of ‘cooking’ information.

So in the end, you do get form following function. And because of changing requirements and materials, you also get new forms?

Yes. That’s also actually where we can learn a lot from nature. Through biomimicry in design we can look to nature as a tool. Because nature always contains ingenious solutions that you would not think of. That’s also why I think the design component is not the most complex part. There is of course an aesthetic field, but if you do the process right, there will always be something interesting to cook. And that’s the nice part about being a designer, you get to discover things.

What would you predict will be the most likely aesthetic for the New European Bauhaus that will define this time?

I think the most worrying development that I see in the design industry today is an over focus on modularity in the construction industry. While I understand the benefits of such an approach, I believe that buildings should to evolve from the design process. If we start a design project with a Lego brick, we will end up with buildings that all look the same, and that all perform the same. They can of course be very clever. We can start with a very smart flat-pack system, where we can assemble a box together in an efficient way, and then stack these pixels together. But I don’t think it’s the right answer, because it will lead to a new uniformity in design. All these buildings will start to look the same if they ignore the component of discovery. I'm not against the development, but I'm worried that if this were to become the overriding new school of thought concerning how buildings should be designed, we would be returning to a kind of uniformity that that we had fortunately moved away from in recent decades.

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