Rapunzel Besucherzentrum. Photo: Markus Guhl

We need to bring people, space and the environment back into harmony

The current debate about a responsible quality of life shows a fundamental change in our society that goes beyond the issues of environmental protection and the climate crisis. In Germany, the focus is still on the operation of the building. Sustainability is often reduced to efficient system technology. Instead of highly complex technical systems that are very costly to tune and maintain, we should rather think about the “intelligent” use of carefully selected materials and strive to avoid technical solutions in the first instance. At the Danish conference Biobased Building Materials 21 – 22 August you can hear more about this way of thinking when Martin Haas, professor, founder & partner in haascookzemmrich STUDIO2050 goes on stage. He will also explore several architectural constructions in which biobased building materials have been used.

Before the conference, you can read an interesting interview with Martin here.

What is your background, and how do you work with biobased building materials in your daily work?

 In our architectural office, we have been working for 12 years now on concepts for architecture that can become more resource-efficient and, ideally, climate-neutral. Our focus is not only on structural solutions but also on the consideration of fundamental questions such as the need and the demand for comfort and the long-term benefits of a building project.

A key issue for us is also weighing up whether greater efficiency always achieves the desired overall ecological effect. In a holistic view of insulation, for example, the consumption of resources and the energy required to manufacture and dispose of the material must also be taken into account. Likewise, the type and duration of utilization still play a far too small role in the consideration of the ecological effect of a building measure. The energy and resource requirements per square metre and year are measured. The duration and intensity of actual use are not assessed. However, it makes a clear difference whether the building, once constructed, with its high proportion of integrated energy, is only available to a few people in a limited time window or to a maximum number of people on a permanent basis. Ideally, architecture should be used by many people 24 hours a day, every day of the year, in order to justify the cost of construction.

Martin Haas, professor, founder & partner in haascookzemmrich STUDIO2050

During our work on our project for Alnatura, where we drew up life cycle assessments, we realized that effectiveness in terms of resource conservation is often in stark contrast to efficiency. For example, insulation thicknesses of over 5, 6 or 8 cm are critical in terms of overall ecological resource consumption when it comes to the effective conservation of resources. Above 6 or 7 cm, the thermal insulation loses its effectiveness in relation to the cost of this thermal insulation. Furthermore, we have experienced that the use of resource-saving building materials or cycle-oriented construction very often comes into conflict with our DIN standards in Germany. Clay as a building material, which is still not authorized, had to be checked at great expense in individual cases to determine whether it is permissible, and it is more likely to promote plant technology than to simply support building in order to reduce plant technology.

What should we be particularly aware of when building with biobased materials?

From my work as a board member of the DGNB (German Sustainable Building Council) and in our office, I am familiar with the problem of the discrepancy between the technical performance of a building on the one hand and its actual effectiveness on the other when it comes to taking a holistic view of the issue of resource conservation. Here in Germany, the operation of the building still takes centre stage, and climate protection and sustainability are often reduced to efficient system technology. In doing so, we forget that the material-related aspect of a construction task is essential and must be considered for the CO2 neutrality of our built environment.

Instead of building highly complex and material-intensive technical systems, which are very costly to coordinate and maintain and which greatly increase the proportion of grey energy in buildings, we should rather strive for an “intelligent” and material-appropriate use of carefully selected and bio-based materials. Here it is not the use of new, resource-saving technology, but the attempt to avoid technical solutions in the first instance that is at the centre of all these considerations. The aim must be to simplify our buildings in general with a focus on long-term utilization. It should be noted that our requirements for buildings must be critically scrutinized from this perspective. Does it make sense for us to continue to take 27 degrees as the maximum temperature in a building as a basis in the face of climate change? Do comfort issues that are set out in DIN standards need to be critically scrutinized for their resource-consuming effects?

What do you see as the biggest challenges and opportunities regarding biomaterials in construction?

We must succeed in promoting first and foremost a material-friendly, microclimatically optimized, resource-neutral and, if possible, regional construction project that avoids a large proportion of unnecessary grey energy on the basis of these criteria. In this catalogue of criteria, the technical installation of a building should only fill the delta that resource-friendly and material- and microclimate-friendly architecture can no longer achieve in order to meet our comfort requirements. In connection with our comfort requirements, it should be mentioned that much of what is defined in terms of necessary room conditioning must be checked for its meaningfulness. We must not forget that our DIN standardization and our entire building legislation in Germany largely dates back to a time when resource conservation was not the top priority.

Grey energy, i.e. the value of raw materials, has so far been neglected when it comes to balancing a building. When this topic comes to the fore, as in our project for Alnatura, we even experience resistance. It was not easy for us to get rammed earth on this scale, with three storeys and geothermal wall heating, through the usual building standards in Germany, although the life cycle assessment showed us the clear advantage of this building measure over other materials. In this work, we were able to see that our standardization often stands as an obstacle to a resource-neutral building culture.

Can you suggest three ways for advancing the use of biobased building materials in construction?

From our work, we know that the materials and transport costs are essential for the overall ecological consideration of a building project. When we develop buildings and prepare a life cycle assessment, not only the operation of the building but also the transport, recycling and production of building materials are key factors. Nevertheless, the assessment of sustainability in Germany focuses on the purely technical performance of the building and neglects the integrated and resource- and material-specific energy criteria. It must also be recognized that resource-saving construction can dispense with a large proportion of the energy involved if materials are assessed holistically. Local, easy-to-remove, easy-to-assemble and recyclable building materials not only retain their complete energy performance over the cycle of one-off construction, but can also be recycled.

A life cycle assessment also showed us that CO2 binding in timber construction is only really effective if wood remains in permanent use as construction timber and is not burnt after a single use. We also had great difficulties in the recycling of found building materials such as the re-use of former roads and sealed surfaces, as complex test runs made this recycling difficult for us. In my opinion, there is a need to promote and actively demand that these obvious material stock extensions be examined before the use of newly produced building materials is considered. The principle should be reversed here. Our industry and our building culture are still geared towards everything new and everything factory-fresh, and the recycling and long-term utilization of building materials is the second choice.

Which projects do you find exciting when it comes to biobased materials, and why?

Fortunately, there are more and more very good projects that deal with bio-based materials. Our design process for each project usually begins with an initial approach that can optimally utilize all the microclimatic advantages of its surroundings through a clever orientation and arrangement of functions on the site. We examine the qualities of the site in terms of lighting, ventilation and the procurement of resources.
How would we have to build on the site if we had no energy sources available and all raw materials were extremely limited? In most cases, this approach helps to find a robust and simple solution, which then also manages with less technology in the further development and basically works well with the microclimate of the site. At the beginning of our project for Alnatura on a conversion site in Darmstadt, for example, we tested numerous design approaches to find out how we could create optimal conditions for the 500 employees at this location with the neighboring forest through a clever orientation and building shape. Once the ideal geometry for the location had been developed, the materialization of the cubature was decided on the basis of a life cycle assessment. Rammed earth turned out to be a good solution for a façade with a geothermally powered wall heating system and we were able to develop the project further together with Martin Rauch and his team. After completion, it quickly became clear how much the users appreciate this building because of its approach to the microclimate and the materials used, and enjoy spending time there because they feel that this house is good for their health and enriches their daily lives.

The approach of circular material cycles – less waste, more recyclables – guided us in our competition entry in Stuttgart for the Stöckach Areal, a former industrial site of ENBW. The existing buildings were to be preserved as much as possible and activated through refurbishment, as the industrial structures had good usable proportions. Simply activating the existing structures did not achieve the desired density in the neighborhood, which led to a redensification and the question of which structures could be added. Together with the Technical University of Munich and Transsolar, we developed a concept for how a resilient city could be realized for the planned neighborhood. This showed that although many things are possible in terms of planning, the goal of a CO2-neutral future depends on whether society is prepared to break down and share the traditional division between the functions of living, working and leisure. A number of buildings in the immediate neighborhood of the New Stöckach are being demolished, creating ideal conditions for securing raw materials, creating material passports and reusing construction elements. Our implementation strategy for one of the buildings in the Stöckach area is to first check all available secondary raw materials in the neighborhood for their recycling potential and only replace them with primary materials in case of doubt. The taxonomy has created a dynamic that leads us to expect a rapid readjustment of waste and product legislation in the Closed Substance Cycle and Waste Management Act, which will simplify reuse. The construction and maintenance of buildings should be designed for long-term use. Climate adaptation, circular thinking and the development of existing buildings with a focus on conversion must be transferable beyond the building to the neighborhood, the municipality and ultimately to the whole of Germany. The basis for well-thought-out overall concepts with sustainable resource and space management is an intensive examination of the context.

Our recently won competition for the Königstrasse 1ab in Stuttgart will set an example for the conversion and subsequent utilization of existing buildings. The careful and thoughtful use of our existing resources is the key to a building culture that becomes a model by means of cleverly constructed buildings and regionally differentiated materials and construction methods.

The project focuses on sustainability and the efficient use of resources. A resource-efficient circular economy must work to utilize all available and recyclable secondary raw materials in construction in order to replace primary raw materials. A high degree of recyclability can be achieved due to the disintegrated construction method and predominantly plugged and screwed component connections. The proposed preservation of the existing building in combination with the addition of a timber construction and the maximum use of secondary building materials, including in the load-bearing structure, can save approx. 968 tonnes of CO2 in the life cycle assessment of the construction compared to a completely new building in timber hybrid construction. Our implementation strategy initially envisages checking all available secondary raw materials in the existing building for their recycling potential and only replacing them with primary materials in cases of doubt. For all additive materials, sustainable, renewable raw materials are selected that enable future dismantling in an additive construction method.

What will you be talking about at conference Biobased Building Materials, and what do you hope the participants will gain from your talk?

Our world is changing. The debate about a responsible quality of life is also an expression of a fundamental change in society that goes beyond the issues of environmental protection and the climate crisis. As designers of patterns of organization for human coexistence, we architects have a special role to play here. We need to bring people, space and the environment back into harmony. We can help society find ways to lead a more “sustainable” life. Our built environment influences behavior, habits and social developments. Architecture creates living spaces and provides a framework for social interaction. Every building, therefore, also has a social function. In our networked knowledge and information society, people hardly distinguish between work and leisure anymore. Today, the desire for quality of life and a self-determined environment determines both our working and leisure lives. The individualization of society requires diverse and adaptable building structures in order to meet changing demands. And if we want a building to be used in the long term in order to justify its existence and the expense of its construction, it must be so good that it enriches the lives of its users in the long term and also provides tangible added value for its surroundings. Consideration of the human scale and the best possible integration of the building into its cultural and microclimatic environment is an essential building block for this.

Do you want to hear more about biobased materials from Martin Haas?

At the conference Biobased Building Materials the 21 -22 August you can hear an interesting presentation with Martin Haas on several architectural buildings in biobased materials and his way of integrating the materials. Read more about the conference and sign up here.

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