Interview of H+S

from DETAIL

 

Glass and Colour – An Interview with Matthias Sauerbruch

 

Detail: The name Sauerbruch and Hutton immediately conjures an image of colour- extremely colourful architecture perhaps. Colour has become your trademark. Is that deliberate, or does a label like that bother you?

 

Sauerbruch: Colour has certainly become an architectural means of expression for us, just as brickwork, concrete or other materials have for other architects. I imagine that will remain so in the future, regardless of the kind of projects we undertake. Colour is, if you like, one of our passions; but it's only part of the picture. There are other elements as well, which may not be apparent at first sight.

 

Detail: Where does this passion for colour come from?

 

Sauerbruch: That's hard to say. In my case, it's part of my biography. My father was a painter, and from an early age I was interested in painting and art, The use of colour in our architecture, though, was something we came upon by chance. At the end of the 1980s, when we founded our office in England, a lot of our work involved the conversion of small terraced houses. In many cases, the constructional scope was very limited, since most of the clients had only a small budget at their disposal. At some point, we realized that it was possible to exert a great influence on the spatial effect of even relatively small rooms through the use of colour. For example, you can dissolve the strict angularity of a corner situation with the aid of two colours that are strongly contrasted with each other or that have different degrees of luminance. If you apply this knowledge in a strategic way, a sense of breadth and spaciousness can be achieved where it doesn't exist, physically speaking. We continued to experiment with colour and later used it on planar surfaces; for instance, to lend a facade a visually three-dimensional quality.

 

Detail.' At what point does colour enter the design process?

 

Sauerbruch: It varies from project to project, but usually a basic idea emerges fairly soon as to what colour will play a role - in the facade, say, or at a certain point in the building. Reaching a decision in favour of a specific colour or combination of colours is normally a lengthy process, however. In the case of the Federal German Ministry for the Environment in Dessau, which will be completed in the near future, we applied various spots or patches of colour to the facade in the first competition model. They looked a bit like sliding shutters. The idea came from the office complex in Berlin built for the GSW housing developers and from the photonics centre in Adlershof, where the sun- shading elements are coloured. The ultimate outcome of all this was a coloured glass cladding that is used to conceal functional elements such as night-time ventilation flaps, or that acts as a lining to solid walls. The colour spectrum that runs round the building is subtly differentiated and resulted quite simply from the spatial configuration. We attempted to respond to the different spatial forms with different colours and to reflect the specific context. It was a long development process, which ran parallel to the almost seven-year planning period.

 

Detail: Do you develop your own colour concepts, or do you have a colour consultant?

 

Sauerbruch: No, we do it ourselves.

 

Detail.' Based on what criteria ?

 

Sauerbruch: By a process of exclusion: trial and error. Our colour concepts are not derived from a theory like the one drawn up by Johannes Itten, which is based on special colour groups and luminance values. In our case, it's a visual process, a bit like painting: you study an elevation or a model as if it were a canvas and begin to compose, and you carry on until you have the feeling that it's right. At the beginning, we have a general idea and approach the final concept via a number of variations, using sketches and ever larger models. That usually takes place shortly before the tendering phase. Then we do a facade layout. In the case of the Environment Ministry building, which has a facade roughly one kilometer long if you count the external and the courtyard faces, we first had a model built at 1:200 and actually applied colour to every area. We then repeated this to a scale of 1:75 with colour samples from the Natural Colour System (NCS) range; and after tendering and the award of contracts, we obtained the samples from the firm. A further difficulty was the fact that when you put a coating on the rear face of glazing, the green tone of the glass has a strong influence on the coloration even in the case of so-called "white" flint glass. Red shades appear much duller, for example. We had to try out some colours four or five times to achieve a satisfactory result on the outside.

 

Detail: A striking feature of your work is that you use colour very often in combination with glass. At Adlershof, for example, you seem to play quite consciously with the aesthetic potential of reflections.

 

Sauerbruch: In some cases, reflections provide an additional spatial-material dimension. In the recently finished police station and fire-brigade building in the parliamentary district of Berlin, the reflecting surface of the glass cladding lends the structure a certain lightness, which forms a pleasing contrast to the dull brick surfaces of the rather heavy existing building. A further aspect, of course, is the durability of the applied colour. Coating glass on its rear face produces a lovely colour finish for facades that is lightfast, protected against the weather and durable.

 

Detail: How do you apply your colour concepts to internal spaces?

 

Sauerbruch: That depends on the individual project. For example, the research building in Biberach, which we completed roughly a year ago, has a striking coloured skin externally, whereas internally, the coloration is relatively subdued. There are certain areas of colour, of course; at the same time, the so-called "white walls" are often not really white, but have a light, restrained coloration. What is more, the colour of the facade usually radiates through the windows of the laboratories. In the factory in Magdeburg, on the other hand, there is a more pervasive colour concept. The exterior of the building and the inside of the entrance area are extremely colourful. The foyer-like space is the only collective place where everyone can come together - for exhibitions or receptions, for example. The coloration is meant to signify a public realm and a sense of community.

 

Detail,' Let's go back to the facade in Biberach for a moment Is it true that the striking coloration is based on a molecular structure?

 

Sauerbruch: Yes, that is really true. On the Internet, we found an electron-microscope image of a substance made by the client and enlarged it even more. To be quite honest, though, we changed the colours a lot, and bit by bit the structure as well. Symbolically, I find the notion of delving into a molecular world something very beautiful; and it's also related to the research people, who are concerned the whole time with microscopic views and immerse themselves in things at quite a different scale. Only those who are aware of this connection will get the point; for the average observer, it's simply a colour composition.

 

Detail: And how do the research people accept the actual facade? Don't they have to put up with coloured light internally because of the coloured glass?

 

Sauerbruch: The body of the glass is not coloured. The surface is printed with a grid of dots. The coloration is relatively restrained, and the coating itself is not permeable to light, or hardly so, The shadows cast by the grid of dots have no colour, therefore. Naturally, colour reflections do occur, so that the light internally has a slight but very subdued coloration.

 

Detail.: And this coloration doesn't disturb the users? What are their reactions?

 

Sauerbruoh: The reactions go both ways, of course. Some people are disturbed by the coloration, but the majority like it. In the police station and fire-brigade complex in Berlin, which I mentioned earlier, the entire facade is in a fairly intense red and green. Laid over the windows is a louver structure, and when this is closed, even the windows gleam in a red tone, rather like a night bar. When the louvres are tipped open, however, the space is entirely white again. Anyone

 

Detail.' Is the glass treated differently there? What kinds of coloured glass did you use - coated, enameled, with layers of film - and what experience do you have of their use?

 

Sauerbruch: In principle, the same technology was used in both projects; but in the case of the fire station, the printing was somewhat denser and the colours are more intense, so that the reflections are also stronger. Here again, though, the light that falls through the printed glass is not colored. It is the printed layer itself that radiates, In the showroom for the Zumtobel Staff lighting concern, in contrast, we used real coloured glass - laminated glass with a coloured film adhesively fixed between the layers. Here, the light entering from outside through the glass really is coloured. In this case, it was intentional; we wanted to create a stark contrast between the ingress of daylight from outside and the artificial lighting from the lamps in the exhibition. At night, therefore, the effect is reversed: when the lighting is turned on internally, the facade becomes an illuminated box or lantern.

 

Detail: In the case of the fire station, what is the technical purpose of the glass skin with louvres set outside the facade?

 

Sauerbruch: In the first instance, it provides sun shading, as well as wind screening for the open windows to the rear, It is net really a thermal buffer, though, as in the facade of the GSW building in Berlin or in the photonics centre.

 

Detail: Is it possible to open the louvres individually?

 

Sauerbruch: In the case of the police station, they can be adjusted individually for every window - in other words, over the entire window area. The casements behind the glass skin can be opened according to a certain rhythm.

 

Detail: How did the colour scheme come about?

 

Sauerbruch: It was a free composition, whereby red represents the fire-brigade and green the police.

 

Detail: Don't the inclined coloured louvres diminish the exploitation of daylight within the building ?

 

Sauerbruch: The windows are quite generously dimensioned in relation to the room sizes, so that this problem doesn't really arise. In the case of the Environment Ministry building, we made detailed studies for the window sizes. The proportion of the glazing area is an important aspect if one is talking about ecological forms of construction, We made a precise analysis of how small a window may be to ensure an optimum illumination of the workplaces yet at the same time to keep heat losses in winter and thermal gains in summer to a minimum. The outcome of these studies was about 40 per cent externally and 65 per cent internally. Solar screening here consists of highly reflecting, coated louvres, which also function as light deflectors. From an ecological point of view, it was important to ensure a good balance between the building volume and the floor area, thereby reducing the area of the facade.

 

Detail, We're now into the realm of ecology. Can you say a little more about your solar concept or the ecological concept for the Ministry for the Environment?

 

Sauerbruch: The Environment Ministry began as an extremely ambitious project. As early as the competition stage, the participants were required to develop prototypical measures. Later, many of our suggestions were rejected, although they were solutions that are generally regarded among architects as having a positive effect: the double-skin facade, for example. There are specialists in the ministry who investigate all these matters on a scientific basis, but the clients themselves - the building authorities and the ministry - reacted somewhat conservatively because of negative experiences they had had in the past. I can understand that; taxpayers' money is involved, after all. Ultimately, therefore, the concepts are not as new as one might have wished.

 

Detail: Do you think an opportunity was missed here, in such an important project as the Ministry for the Environment, to make the public - and architects - more sensitive to ecological forms of construction?

 

Sauerbruch: No. You can't say that. On the contrary, there are numerous examples here of an ecologically meaningful approach to construction. It's just that one can't claim it was done for the first time in this scheme.

 

Detail.' What are the distinguishing features of the ecological concept as implemented?

 

Sauerbruch: First of all, the high level of thermal insulation. We exceeded the levels defined by the insulation regulations valid at that time by 50 per cent, and the energy-saving requirements by roughly 30 per cent. We also exploited regenerative forms of energy - from photovoltaic and solar-heating systems, for example. In addition, the cooling plant for the canteen is run on solar energy, and there is a small cogenerating unit for electricity and heating that is operated with fuel cells (as a demonstration model). The most spectacular measure, though, is the geothermal heat-exchange plant. External air is drawn in and pretreated thermally via a roughly five-kilometer-long pipe system laid in the ground. In this way, the building is supplied with cool air in summer and warm air in winter. As far as I'm aware, it's the largest installation of its kind in the world. I should also mention that the federal authorities participated in a plant that produces gas from waste matter, from which electricity is generated for the Environment Ministry building.

 

Constructional biology, or the selection of building materials, also forms part of the ecological concept in terms of primary energy. It's a discipline that's still in its infancy; for although it is possible to speak about concrete, aluminum, glass or timber in general, one has to differentiate between various kinds of cement, glass manufacturing processes, recycled or newly extracted aluminum - to mention just a few things. The whole team received advice from consultants in these matters. In collaboration with the Society for Ecological Building, we drew up a catalogue of measures on the basis of which a timber facade was specified for the building, That was just one aspect. The fact that a timber structure was used and not just wood cladding is something rather spectacular for a four-storey office building of this size. In the process, we also learned that timber is not without its problems as a building material: at the end of its life, when it ultimately becomes a waste product, it is difficult to dispose of wood if it has been treated with a preservative. We also had to specify that the timber should come from native forests; otherwise the whole ecological advantage would have been lost through transport. We at least attempted to do something in this direction. The same applies to the paint, the flooring and other finishing materials, which bear the "Blue Angel" sign (a quality seal issued by the Ministry for the Environment). Where that is not the case, we relied on our consultants and on test results. In general, materials were selected from the standpoint that they should require a minimum of energy for their processing, installation and disposal and that they should be safe in terms of building biology.

 

Detail  Would you say that the extra costs involved in this scheme were economically justifiable?

 

Sauerbruch: Since we were able to set the life of the building at 50 years in our calculations, all the measures we implemented were economically justifiable. I see that as a positive sign, even if a developer would certainly not accept this argument, because he reckons on an amodization period of seven to ten years for his buildings and tends to ignore the operating costs. The results are all the more a point of reference, however. for people who wish to advance the cause of sustainability.

 

Detail: While we're on the subject of the life of a building, sustainability would seem to be an important aspect for you. Some of your other developments, such as the GSW in Berlin, contain elements of solar technology, even ff not to the extent of the ministry building. At the same time, your designs are strongly oriented to current tastes. Does that not contradict the idea of sustainability?

 

Sauerbruch: I have no problem with that. In the history of art and architecture, it's nothing new for a building to be very much a child of its time and yet to survive. In that respect, the question of contemporarily or fashionableness has nothing to do with quality. Quite different criteria are involved in that: how well does a building function; does it contribute something to the urban environment; what are its spatial qualities; how well proportioned is it or how well crafted? And all that is independent of the time from which it dates.

 

Detail: Not all modern architecture is as dependent on current trends as your buildings are, though. Don't you think that a building may be erected - like the experimental factory in Magdeburg - that creates a tremendous splash at the beginning, but that one can't stand in ten years?

 

Sauerbruch: I can't preclude that possibility, but quite honestly, I don't find it so terrible. If the building is used and fulfils its function, its users must like it to a certain extent because it makes sense to them. What is more, a structure with a striking character is likely to promote a good relationship with its users. A building that has a certain profile, which provides a sense of orientation and that can be viewed critically is, to my mind, far better than a completely neutral object where you have to search for the identity or character.

 

Detail. Aren’t you afraid that in a few years time, someone will come along and paint everything white or brown or whatever, and your colour concept will be completely ruined as a result?

 

Sauerbruch: That can happen, of course, but we are not so uptight about our architecture. It's a bit like bringing up a child. At some point, he or she becomes an independent person and will be prepared to follow parental guidance only to a certain extent. I experienced something of this kind as a project architect for OMA at Checkpoint Charlie. The building, with amenities for Allied forces, was handed over on 1 November 1989; but after the fall of the Berlin Wall, its purpose was gone - in part, at least. Six months later, it was converted without us. Today, it houses a supermarket, a function that ironically formed part of a provocative concept we considered for the time after the fall of the Wall. Even if that was not really conceivable at the time, it turned out that way, and today it's a quite different building. But it still exerts an enormous sense of power and immediacy, particularly the upper part, and one can still recognize it as a fine piece of architecture.

 

Detail: Then you do not define the individuality of your buildings through their coloration.

 

Sauerbruch: That's certainly one element. If you were to take the colour away, a lot of the character would be missing. It would be a great pity if one of our buildings were painted over at a later date. Maybe it would be worse than it was before, but it would still be a building that, one hopes, fulfils its function.

 

Detail: I imagine that colour is greatly appreciated by the public at large. Do you see the use of colour as a means of making modern architecture popular with lay people?

 

Sauerbruch: Colour is a very emotional element to which most people react in some way or other. To that extent, you're right. Colour used on buildings tends to make the man in the street take notice of an urban development where he might otherwise not. If it were possible to affect more people positively through the use of colour, that would be fine with us. After all, we don't build things for ourselves, but for our clients and the users, and beyond that, for the city or the built environment in which they stand.

 

Detail.' Could you imagine designing an entirely monochrome building one day?

 

Sauerbruch: We have just completed the town hall in Hennigsdorf, which is relatively monochrome for our standards. It is in quite subdued tones, with the exception of the council chamber, which is in a dark red. The absence of colour became almost an accusation that was leveled against us. The client felt a bit cheated, because we normally create boldly coloured architecture. In the case of Hennigsdorf, however, which is a small industrial town in Brandenburg, the specific situation and history of the place seemed to demand greater restraint, We wanted to create a building that radiated a sense of openness and dignity. In the period immediately following the fall of communism, many buildings were created that I would call "gaudy" rather than colourful. We thought the use of materials like oak and bricks were more appropriate to this assignment and the context. We are not intent on using colour in every conceivable situation. We seek to match the prevailing conditions.

 

Detail: How important are different materials for your architecture? Do you always rely on materials of a similar kind, or is there a greater variety?

 

Sauerbruch: Where colour is involved, one is limited, of course. Coating technologies have developed enormously, but painted finishes last for a maximum of ten years. With stove-enameled glass, on the other hand, the durability and lightfastness are fairly high. That's why we try as far as possible, where facades are concerned, to use materials that have a relative constancy. We use glass a lot not only for its reflecting surface, but because it has a beautiful quality and is durable. Problems arise when coloured metals are used and special sections have to be recoated or painted, because they cannot be precoated and then bent to shape as in the manufacturing process. When we use natural materials in conjunction with coloured surfaces, we try to use products that have a certain haptic quality and are contrasted with the neutral, coloured surface, Stone, wood and ceramics are examples of this. I also find the combination of coloured surfaces and wood very attractive.

 

Detail: Thank you very much for this interview, Matthias Sauerbruch was interviewed by Christian Schi Rich in Munich.

 

 

Matthias Sauerbruch, architect

1995 Professor at the University of Technology, Berlin;

since 2001 at the Academy of Fine Arts in Stuttgart

1989 Practice with Louisa Hutton in London

1993 Sauerbruch Hutton Architects in Berlin