For us, sustainable design goes hand-in-hand with a comprehensive, contextual and process-oriented approach. The underlying rationale is that the various requirements and parameters of sustainable construction are not something to be applied retrospectively with the help of technology in order to minimise the negative impact of the initial design concept. The goal of our design process is a holistic one: to optimise the design in constant interaction not only with its spatial, social, and cultural contexts, but also with its climatic context. The process is therefore certain to arrive at a highly specific local (and thus individual) solution.
In order to develop a building as an integrated system, we take a critical look at the conventional ways of doing things. To give an example, a floor slab is not only a structural component of the primary structure; it can also be thermally activated and, owing to its high thermal mass, can contribute to the balanced and efficient use of energy in a building. By differentiating the layout in section and on plan to create zones with different climatic profiles, we can not only help to reduce the heating energy requirement, but also allow for a wide range of possible uses and create a variety of internal vistas. We treat buildings as participants in global material cycles. The heating and power requirements are kept to an absolute minimum, based on the low-energy principle. Rather than high-tech solutions, the focus lies on devising an intelligent combination of passive and active measures to make extensive use of the locally available sources of renewable energy. In keeping with this approach, we incorporate technology as circulatory systems rather than 'end-of-pipe' services.
Sustainable architecture is contextual architecture. By this, we mean not only the integration of a building in the surrounding landscape and the built context, but also the many and varied effects that its erection and use have on the environment, society and culture.
The main precondition for creating an identity is the independence and integrity of the built object, so it follows that architecture cannot be derived solely from the context. Exciting spaces, identity and orientation are generated by the sensitive and skilful insertion of buildings that make a positive contribution to their surroundings. The complexity of the various aspects of sustainability makes it necessary to strike a carefully considered balance between the old and the new. We emphasise the contextual nature of sustainable buildings, because we are convinced that these are the aspects that get neglected in many projects as a result of the way in which architecture is practised nowadays and the ever-present forces of globalisation.
Sustainability at an urban level means making a planned intervention that fits into the existing ecosystem, creating something new of equal value and, at the same time, trying to create the optimum long-term conditions for properly functioning community life in densified urban structures. When creating new structures, it is important not only to take care with their spatial, volumetric insertion in the surroundings – urban scale, massing and proportion – but also to consider the local building tradition and social conditions.
The foundation for optimising the most important aspects of sustainability is laid when the spatial composition of a building is being developed. The potential and synergies embodied then at the conceptual level can only be altered subsequently with considerable effort in terms of area, construction and building technology. In most cases, this leads to an increase in the degree of mechanisation and thus to an increase in the costs.
The design process also has to allow for what cannot yet be predicted. By creating flexible-use structures, the environmental impact can be reduced over the entire life cycle, from the construction and operational phases to conversion and dismantling or demolition.
For us, this means placing the emphasis less on strictly implementing floor area requirements than on creating versatile, well-proportioned and well-lit rooms to provide the basis for long-term serviceability. It is not primarily the choice of building materials and components that is crucial to the environmental impact over the full life cycle of a building, but their effective service life. An adaptable, easily used and intelligently thought-out floor plan can extend the service life many times over, before refurbishment or replacement with a new building become necessary.
One of the architect's main tasks is to create a relationship between the content of a building and its shape. At BGP, the architectural composition is not an image that is settled upon at the beginning of the process; it rather arises as the result of an inclusive process of design and analysis. Whereas the massing of a building takes effect at a distance, it is the materials that create a specific atmosphere from close to. Their tactile qualities, surface texture, acoustic behaviour and reflectivity, among other aspects, offer fascinating possibilities of creating spaces that delight the senses.
Beside the aesthetic and technical properties, the environmental and energy-saving performance is becoming increasingly relevant. The proposed tightening of statutory energy requirements will change the balance between embodied and operating energy in the future. Going by the objectives set in the EU directive on buildings, we may assume that from the year 2021 onwards, any new building erected in central Europe will require only about as much energy to operate – based on a period of fifty years – as was used in its production. The focus of attention will therefore shift to the life-cycle assessment of materials, components and structures. In order to reconcile these needs with space requirements and design ideas, we use open-ended design and planning processes and explore the potential at every level.