Time and again we see evidence that we stopped expecting buildings to last for eternity many years ago. No sooner the first signs of patina appear on a building – after twenty, thirty or forty years – people start discussing whether it should be torn down, or whether it would make sense to renovate it after all. In a recent interview, DGNB CEO Dr Christine Lemaitre and Thomas Auer, professor for climate-friendly building at the Technical University of Munich, explained why that doesn’t have to be the case.
This interview, which took place as part of the Bluebeam/Nevaris Online Talk on 11 October 2022, was conducted by Tim Westphal, a journalist specialised in construction and digitalisation in the building industry. A full-length version of the interview in German will appear in the print and online version of trade magazine Build-Ing.
Tim Westphal (TW): The DGNB has tight overlaps with the issue of building life cycles. There’s a lot of talk at the moment about the term itself, but it’s still a bit abstract. How does that impact the DGNB?
Christine Lemaitre (CL): One thing I’d say is that the topic’s finally reached the masses, although it’s not important what the DGNB or I personally say about it. When it comes to life cycle assessments, i.e. understanding the net environmental impact of a building, there’s an international standard. It captures everything in clear terms. It gives you an outline of the entire life cycle, including the construction phase of a building – overarching concepts affecting how everything interacts, the materials you’re working with, the emissions you’re creating in production, and how the building’s used. The same applies to costs. It’s not just about examining building costs, but also operating outlays and maintenance costs – right up until deconstruction.
TW: One thing you hear time again and again is that actually, we’ve already built everything we need. Despite that, are new buildings still important – in hand with the goal of showing how resilient architecture can be? Or does that also allow any kind of existing building to come up with something new?
CL: It’s a bit of both. We’re currently seeing an emergence in the community of architects of a new appreciation of existing building stock – seeing existing buildings as an exciting area to work in. That’s exactly what we need. We’ve done an insane amount of building and this offers tremendous potential to work with existing buildings – to refurbish, convert or repurpose them. This usually starts with getting them to operate properly. On the other hand, we can’t entirely do without new buildings. That’s especially true of infrastructure projects or special buildings like schools, hospitals and nursing homes.
TW: Thomas Auer works at the interface between architecture, engineering and technology. Lecturing at the Technical University of Munich is an important responsibility for him. He fosters a strong understanding of adaptable building – of resilient architecture that conserves resources by using technology sensibly. Thomas, how important is the building life cycle to your work at the university chair?
Thomas Auer (TA): The actions we take and the things we plan should always be based on life cycle considerations. This is something we’re trying to establish. We’re not actually conducting research ourselves at the chair on life cycle assessments or calculations. We’re more concerned with questions about the qualities we need to establish, including quality of space. We like to refer to the ‘unseen qualities of architecture’ – like, how do you create buildings that people feel comfortable in? This already allows buildings to establish a basis for lasting longer. But also, with technology it’s sometimes about quite mundane issues, like what you do with fittings and equipment. That’s because they don’t last as long as the building structure. Something we’re also seeing at the moment is buildings from the 1970s and 80s being knocked down just because the technology’s outdated. So this raises some important questions: which technology does make sense, and what options do you have for installing the technology? What can we do to engage in architecture in such a way that the technology is interchangeable? How do we deal with life cycles within each individual manual trade – right from the initial planning stage?
TW: We know adaptable architecture is an issue we need to tackle. It’s just there’s no silver bullet. Although maybe people have an idea of what to look out for?
TA: One measure that always helps is room height. Lots of 70s buildings with obsolete technology do actually get torn down because they’re not adaptable enough to have new systems installed. And then there’s the whole data infrastructure we need these days – rooms for servers and things like that. One approach is to give buildings a so-called loose fit, which makes things more adaptable to future use. Of course there are other things you can do, too. I also think you can achieve a lot by making floor plans adaptable. But to achieve a loose fit you need to use more materials. To what extent these ideas will make things more adaptable in the future is a matter of speculation.
CL: We come from a time when there were pre-formulated room concepts that were virtually strung together. When you talk about life cycle assessments, you’re also referring to the tools and methods we now have at our disposal. You could argue that higher ceilings mean more materials, but instead we need to ensure the approach used to conduct life cycle assessments becomes the new normal. I’m certain that even if ceilings are higher, we’ll still move forward by looking at eco-sufficiency and asking how much space you need in the first place. We’re coming from a mindset that’s about introducing measures and always having a solution up your sleeve, without even knowing where a building is and what actually needs to be built. In situations like that the really important tools are the planning methods, based on the life cycle – looking at the net environmental impact and life cycle costings. We’ve got to demystify these methods – soon – and make them known.
TW: Isn’t that basically the way our architecture has developed over the last 40 or 50 years? That it’s always about maximising profits, cost-benefit calculations and break-even points – how quickly you can get your building back into the black and how you get your money out of it again. Will that also be the goal in the future? Or shouldn’t we start focusing again on human factors?
TA: This is one of the biggest problems we face. We keep saying architecture’s a snapshot, a still of the mindset in society at a certain time. For example, you can see that post-war architecture was about resources and the money shortage. That’s how they built back then, and when it came to material use, building was actually quite sustainable. The ceilings were made out of precast elements, such as ribbed slabs with much less concrete than we now use. I do wonder what sort of impression future generations will have of the way we build today. They might think this was an era primarily driven by money. I’m afraid that’s the image we currently portray.
CL: One thing that’s worth noting is that sustainability has made its way into the commercial property industry, because Brussels is now really pushing the EU taxonomy. Life cycle assessments are a central element of this. It’s already noticeable that the financial institutions and insurance companies are rethinking things. It’s no longer about maximising profits. What’s important now is risk reduction in times of severe weather extremes – so I could point to problems with pollutants and overheating, and in the winter problems with cold buildings. The onus is on architects and planners to incorporate such aspects into their projects. What’s built for commercial purposes is one thing. But private construction needs to be highlighted as a big issue to local communities, since affordable housing is their responsibility. It’s not international investment funds building residential properties in towns and cities. We also need to ensure we stay well informed and give the right advice on this. These days, when you talk about buildings the topics are completely unlike the important commercial topics.
TW: Most construction in the post-war period was about cost efficiency. That also applies to buildings that until now haven’t been used for other purposes, such as hospitals. With tailor-made buildings like those, is it possible to find sensible ways to reuse or repurpose them? Or are we probably going to lose them?
TA: Hospital buildings are too special to say what would work on a general level. That said, I’m currently advising a client on the conversion of a former Karstadt building dating back to the post-war period. And yes, it’s a difficult one. It’s a former department store from the 1960s and putting it to a different use is a major challenge – and that starts with the scale of the building. The ceilings will have to be upgraded or in some cases replaced. It would be a lot easier for the developer to raze the whole thing to the ground. But as Christine already said, things are moving forward now, even from an economic standpoint. One important argument in this respect is the EU taxonomy. Developers are also rethinking things. So I’ll say it again: there are very few reasons why tearing down a building is absolutely necessary!
TW: Is there a need to introduce funding models or legal requirements? Or should the market sort this thing out by itself?
CL: I think if you want to assess the whole life cycle you need ideas and thinking from all angles. The market won’t sort this thing out by itself. Some parts of the market have recognised the issue, however, and taken it on. What I can say is that everyone that’s been certified by the DGNB since 2009 has had to conduct a life cycle impact assessment, carry out life cycle calculations, work out the costs and provide evidence of other life cycle factors. That said, we don’t certify everything that’s built. So it’s important that everyone gets involved; on a fundamental level this is about ecological progress. The rules we use have established a high quality and energy standard for building envelopes, and because of that efficiency factors have made their way into the planning and building processes. But a number of years ago we reached the point where further efficiency improvements stand in no proportion to the bottom line. Instead, we need to reduce carbon emissions. And the right tools for doing that are the methods of assessing and analysing the life cycle.
TA: Quite soon the old Effizienzhaus standard will no longer be enough by itself. You’ll then need a life cycle assessment to get funding. The same thing could happen with renovations, which make sense in that area because you get a kind of credit; when you erect a new building it’s always its shell that accounts for the most materials, or the most CO2. If a building’s fifty years old, the building shell is ‘written off’ in the life cycle assessment. So it adds a zero to the bottom line. That gives you a big bonus for the overall life cycle assessment. If that becomes a requirement for renovations, we’ll get the right kind of leverage for a funding programme.
TW: The certification offered by the DGNB has international recognition. But compared to LEED or BREAM, in some areas it’s described as complicated. Is DGNB certification really more complex?
CL: We’re certainly more ambitious. If you’re just looking for a sticker to put up outside the front door, something to achieve with minimal effort, the DGNB service isn’t the right choice. We take a more holistic approach; we’re more precise with a lot of things – so we’re typically German. The DGNB system is based on a different planning culture. I often hear that it’s too difficult. And then I think to myself: who goes and studies architecture or engineering because they want a job where they just sit there and go through checklists? Surely building is a bit like solving a puzzle; it’s a challenge. That’s why I find it a bit sad if sustainability is only important from a marketing standpoint – it’s always about coming up with a catch-all solution for the planning and decision-making process, and ‘thinking about it for a moment’ is too much of an effort.
TW: Although to give all due credit to LEED and BREAM, it has to be said that it’s not actually that easy getting the sticker outside the front door.
CL: Those certificates have certainly achieved a lot within their own cultural environment. But they revolve around a different planning culture, different legal frameworks. It’s obvious I’m against one-size-fits-all mentalities. We’ve got to avoid starting to build here in Germany like they do in the USA or other English-speaking countries.
TW: Globalisation doesn’t work in all sectors of the economy. We noticed this during Covid and the bottlenecks encountered with raw material supplies, the component shortages, in machine-building and vehicle construction, or in computer technology overall. Should we start thinking more locally again – maybe when it comes to building, the materials that are used, how they’re re-used, or overall when it comes to the issue of resources?
TA: The short answer to that is yes. The longer answer is yes … but. Of course we have to make sure we keep transport routes to a minimum. We did a study on a building made with clay; the adobe was only sourced from 200 kilometres away. But we decided to go into the detail and counted the number of lorries involved. It was part of the research project. Transport had such a negative impact on the life cycle assessment of the adobe walls that you could question the whole concept. It was something we hadn’t really understood before that. Transport is an important factor, especially with heavy materials. Often you don’t have a proper grasp of where materials come from. You’ve got to look much closer at it. With local materials like bricks, we do have a good grasp – bricks don’t come from India or China. With timber buildings we can also make use of our own materials. You can also get wood certified or ensure it comes from sustainable and renewable sources.
TW: The architect Florian Nagler developed three experimental houses based on simple and sustainable construction, and they’ve garnered much praise and media coverage. What do you make of them?
CL: That’s a terrific and wonderful example of course. I’ve had the pleasure of visiting the site three times. I can only recommend taking a look at the project. It’s unbelievably impressive. You walk into the buildings and although they’re so elementary, there’s one feeling you don’t get – the sense that something’s missing! We may even need a new form of communication for this – especially when we talk about ‘leaving something out’ when we’re building, or when we talk about less comfort. This isn’t something you can express in quantifiable terms – nobody can imagine what you mean. But it’s always like you’re discussing what’s missing. The way I see it, his houses are fabulous examples of planning that’s simple and intelligent. You can see the high standards this leads to. And I would never say that means you’re having to leave something out.
TA: I fear I can’t answer that question – for bias reasons. The building was based on the Einfach Bauen research project at the Technical University of Munich. Florian Nagler was in charge of the project and my chair was allowed to participate in it. So although I’m biased, my answer is that I think the houses are superb. Of course it’s not wrong to argue about the look, the design and the approach taken. But that would be an argument worth having, because the houses have now been built, because people live in them, and you could ask them what their impressions are. Because we’re trying to evaluate this with sociologists – what we see and what we measure.
TW: Do you think listed buildings that can’t be comprehensively refurbished in terms of energy efficiency might also depreciate in the future? That’s on top of the value that listed buildings effectively already offer to society.
CL: Buildings like that don’t really ‘compete’ with anything. I find this a bit difficult. On the one hand, people working with protected buildings should also feel they’re part of the discussion on climate protection. You have to work out if anything can be achieved with minimal intervention. On a fundamental level, this is an area for political discussion. Everyone’s talking about affordable housing, even those who are otherwise not involved in the topic. We ought to focus first on the low-hanging fruits instead of working on the upper echelons and trying to ‘tinker around with things’. And as for climate protection, we need to urgently get to grips with the buildings being constructed by federal, state and local government.
TA: We’re not so worried about preserving sites of historical interest. If my numbers are right, roughly three per cent of all buildings were subject to or classified under preservation orders. But let’s be honest: when I walk through our towns and cities and hear the federal government demanding that fifty per cent of existing buildings should be energy-efficient by 2030, it gets me thinking! Making buildings more energy-efficient means achieving an efficiency score of at least 55, and under the most cost-effective option that involves an exterior wall insulation system. Regardless of the cladding material you use, the appearance changes – and that would have a huge impact on the appearance of our cities. The Building Energy Act says existing buildings that are worthy of protection can be exempted. But the local authorities find it difficult to define what’s worth protecting. I do sometimes wonder whether we’d achieve more by doing less. We’d be introducing huge obstacles if you’re only entitled to funding if you implement ‘the whole package’. But even with current buildings worthy of protection, or listed buildings, it’s still possible to insulate the top floor up to the attic, or the bottom-most floor down to the basement. In most cases you can fit good windows, use box windows and if necessary use insulating plaster. There are lots of ways to slash energy consumption.
CL: We’ve always imagined we can solve all of this with building measures. That’s also why we need life cycle assessments and after that, methods upon which to base balanced decision-making. But that misses out the issue of operation – what the users of buildings do. We’re under no obligation to conduct monitoring. The harsh reality is that the energy consumption of all buildings in Germany is unknown.
TW: One really important aspect is that the necessary technologies are out there and they could already be used right now. Whether it’s digitech – tools or software, or system technologies – along the lines of alternatives to petroleum-based exterior wall insulation systems – there are now options available. So will the topic of life cycle assessments shift even more centre stage in the next two or three years?
TA: Yes, it will, because material consumption will force us to use raw materials in a circular fashion. If we want to keep building like we do and we want building materials to stay in circulation, it’s important to know what’s being built, where and how. That needs to be evaluated by conducting life cycle assessments, but also by using digital tools that let us archive how building materials are used, so we know what can be used where in the future.
CL: Future use is one issue. The other is how material flows are managed in the here and now. We currently have demolition materials and excavated soil being driven around Germany, on average for 300 kilometres, mostly on the back of lorries. There are also ways to use digitech to manage these material flows differently and recycle materials properly.