Designing renovation of architectural heritage

Most theoretical literature of architectural conservation addresses historical buildings as a heritage that ought to be conserved. Necessity of adaptation to present needs of use is admitted, but not its topic. There is a paradigmatic distinction and a prohibition of categorical mingling between ‘history’ and ‘presence’, which is clearly expressed by the Charter of Venice, until today the internationally most agreed upon manifesto of architectural conservation. The Charter states:

The origin of this ‘distinction claim’ and the legitimacy of its ongoing application shall not be discussed here (for the history of conservation, see Choay, 1992). However, the consequence of this distinction has been that the following question is inadequately addressed: How can a historical building be introduced into a design process?

The caution with which this question is asked becomes more lucid in the literature of the discipline, which contributes most to the practical cooperation of conservation and present architecture, that is, building archaeology. It will be discussed in detail how this discipline produces boundary objects and still, in most cases, does not go beyond the neat distinction erected by conservation theory. An exception in German-speaking countries is Johannes Cramer, an architect and building archaeologist who opts for present planning with old buildings through the understanding of their history (Cramer, 1988, 1993, 1998).

In the English literature, pragmatic approaches to conservation are more common: dealing with heritage management as a political, social and financial issue (Pearce, 1989); and more specifically with the architectural life of built heritage (e.g. Strike, 1994). Strike studies architectural design at historic sites from a realistic and practice-oriented perspective. However, he does not analyse the design process, but uses extant examples to build up a loose system along thematic chapters. Cantacuzino (1989) and Spital-Frenking (2000) follow a similar aim, also starting from examples, but less systematically.

Like ethnography of engineering design (Bucciarelli, 1994; Henderson, 1999) ethnography of architecture analyses design and representational practice with a methodology adapted from Science and Technology Studies (Callon, 1996; Yaneva, 2005), but has never approached renovation design. The same applies for design studies.

Renovation: between conserving and construction

At first sight there is a certain paradox in the nature of an old building. In terms of architectural design, a given building may seem relatively easy-to-understand, simply because it already exists. Generally speaking, for a designer the final structure and shape of his object is unknown at the beginning of his work; and he puts much effort into anticipating and simulating the physical performance of his object, in order to understand the implications of his design decisions and communicate them convincingly. As compared with a forthcoming building, the structure and appearance of the existing building are already visible (unless covered by younger installations which are not considered ‘part of the building’). In order to make it available for the renovation design, it is mainly necessary to transfer the existing construction to a medium of drawing by measurement and projection, which is a standardized procedure and as such not a creative architectural design issue.

On the other hand, a 200- or 400-year-old building – when considered from a more contemplative and not from a construction oriented viewpoint – will to some extent always remain an alien to the modern building and planning process. Alteration occurred continuously throughout a time span of many generations (roughly 12 in case of the Old Aula) in a dialectic of natural and human interventions. Single human interventions may have been accomplished in a pragmatic and rational manner; but the sequential totality of changes has never been understood by any single designer's mind. There is a wealth of heterogeneous qualities and stratifications that will never fully integrate into a present design and construction process; and the historical and aesthetic ‘aura’ of an old building relies on this withdrawal. When referring to this aspect of the building, conservation theory speaks of ‘monument’ or ‘document’, as of something which cannot be understood in terms of architectural design alone, neither going back to the original design of the building nor interpreting the design by contemporary understanding.

To summarize, two ultimate perspectives can be discerned:

• the present ‘given building’ exposed to reconstruction – a perspective in which the history of the building is conceptually and perceptually ‘flattened’ as part of the one present state and thus made appraisable together with new installations and additions (Figure 4)

• the ‘historical building’ that ought to be preserved in the full complexity of its historically grown state (Gazzola et al., 1965, art. 11); this perspective implies every alteration is a loss

Dependent on the intended reuse for a building as well as the attitude of conservators and architects, these two conceptions may result to be largely adversarial and antagonistic. If the proposed reuse has a good fit to the old building's structure, then the two conceptions may also largely coincide and establish mutual benefits. On the one hand: and an appropriate use can highlight the value of a building. On the other hand, the historical value can give a symbolic surplus to the estate, the comfort and (corporate) identity of its users.

Representation and cognition of a building in renovation

What happens to an old building when it enters a renovation process? The question is first addressed within the current paper in rather general terms of representation and cognition.

Bruno Latour has repeatedly described mechanisms of visual and textual representations or ‘inscriptions’ in science, showing the power of ‘immutable mobiles’: objects reduced to a paper surface and enabled to be dislocated and reproduced without changing their qualities. ‘Immutable mobiles’ can ‘draw things together’ from large spatial distances and time spans to a simultaneously surveyable working place (Latour, 1990). Elsewhere Latour (1999) emphasized the ‘circular reference’ according to which the signs of science also have the ability to be retransformed and travel back to the located material things. But even if this way back is important for testing scientific results, correction and extension of data, the main cognitive power of inscriptions resides in abstraction, dislocation, and generalization.

Design, for the sake of producing new objects, goes the other way round. Typically, it collects requirements and starts to organize them in simple structures and shapes, juxtaposing and superimposing them until they get increasingly more complex. The greater the complexity, the more important become 3D simulations and material prototypes or scale models, in order to test the performance of the emerging objects. Even if the design process has to go back repeatedly to simpler, smaller and easy-to-handle representations, the overall process goes from abstraction and simplicity toward complexity and enrichment with contextual respectively local data (Brereton, 2004; Yaneva, 2005).

For both science and design, only the iterative movement between the concrete/local/material/contingent and the abstract/dislocated/compatible/calculable exhausts the full cognitive power of representations; but the main directions are reversed.

Renovation design, unlike the design of a new building, implies both directions: one analytical, going from the given object to representation, and one productive, going from representation to the altered object. The ‘circular reference’ in renovation design differs from the one of basic scientific research described by Latour (1999), since its circle is not only open in terms of cognition, but also ends in an intentionally altered product. The distinct perspectives of architects and conservators can be understood more clearly within this set of representational activities.

The conservators' interests and care for the historical building are represented in the analytical half of the circle. However, their engagement with representations differs from scientists who treat single objects as specimen and aim at making statements about a species or other ‘generalized objects’, which only exist in representations. For conservators, representations have a relative value. They are necessary in practice, for cognitive and communicational reasons, but they always ought to lead back to the building in its uniqueness, incompatibility and contingency. (Art historical classification is implied in the conservators' evaluation of objects, but not its end.)

For architects the analytical representations of the building's survey are an indispensable starting point, but also not an end in itself. It is useful for them to learn about the extant building. But they are likewise interested in a high degree of reduction, in order to gain distance from the overwhelming density of sensual information, to focus on main structural features, and rethink the building's design by bringing the old and the new onto one level.

Communicating about the building by representations

When an old building is first considered for a renovation project, it is so open to different approaches, descriptions and interests that it is no more than a ‘trading zone’ in general terms (for a scheme of three types of trading zones, each of them characterized by a specific kind of representational practice, as related to three levels of expert communication, see Gorman, 2002). It is not yet a ‘boundary object’, which is defined as:

A boundary object can realize its translational capacity only if various actors collaborate somehow (Star and Griesemer, 1989, p. 408). But the actors involved in a renovation project do not necessarily share in one enterprise. Institutionally, conservators are state officials equipped with legal powers to protect cultural heritage. Clients and users, as far as their involvement in the planning, typically want to gain maximum profit from the renovated building and commission an architect to realize that. Therefore, architects first represent their clients. They have to conceive a physical shape that organizes the owners' and users' requirements along with further constraints entailed by building materials and technologies, local context as well as building laws. Furthermore, architects develop this physical shape with a specific aesthetic attention, as a product of artistic creation and symbolic expression; and in this they differ from design engineers. In renovation design, the aesthetic ambition of the architect can more or less align with the symbolic and aesthetic value of the old building, which is officially represented and protected by the conservators. Hence, architects and conservators can collaborate based on a shared understanding of architecture as a cultural and artistic product. However, architects and conservators also happen to take opposing positions and demarcate their domains of action with as little intersection or exchange as possible.

Collaboration can begin early, if owners (or users) and conservators agree in wishing a re-dedication of the building. But this is not necessary for good collaboration, nor does it guarantee agreement about the physical renovation issues.

The Old Aula

In 1623, at the height of the Counter-Reformation, the University of Vienna was brought under the control of the Jesuit Order. For this hybrid institution a large and completely new complex was built – along with the imperial palace the most ambitious architectural endeavour of the city in the 17th century. The entire complex survived the dissolution of the ‘Jesuit University’ and the dislocation of the university from the old centre until today (Figure 1). The Old Aula, the oldest preserved university building of Vienna, still testifies monumentally the hybrid institution. The second floor served as a huge theatre hall with a ceiling fresco for the famous Jesuit theatre performances. Vaulted rooms on the ground and first floor contained classrooms and a festive assembly hall (Karner and Telesko, 2003).

Since the drastic modernization of Vienna in the late 19th century, the building fell into oblivion and slowly decayed under fragmentary and inappropriate uses. During the Second World War it was partly damaged by a bomb. Since the 1970s the ceiling fresco of the second floor threatened to collapse and finally inhibited any use of the room. In the 1980s the Austrian Federal Office for the Care of Monuments decided to prioritize the costly restoration of the fresco and not calculate its costs in the budget of a future renovation project, which was a decisive step forward. At the same time the Austrian Academy of Sciences (OAW), the main user of the Old University Quarter, started searching for an institution that would take over the building for a public, cultural use.

Therefore, the user and the conservators agreed the need to find a new and more appropriate use for the whole building. For the conservators it was also clear that opening the building to a larger public would necessitate architectural interventions that exceeded sole restoration, e.g. the circulation system, which was insufficient in relation to the size of the former theatre hall on the second floor, and technical installations. The owner, the Federal Ministry of Labour and Economy, represented by the ‘Burghauptmannschaft Österreich (BHOE)’, a small specialized institution in charge of managing and preserving such historical buildings, was also supporting the renovation project.

Finally, it was the user, without participation of the owner, who concretized the renovation project by organizing an international design competition with ten invited participants. This somewhat unusual procedure was due to the fact that the renovation was now related to another project of great importance to the President of the OAW, Werner Welzig: that of a new science communication institution, the so-called Gallery of Research. It was intended this new institution should be housed in this building, but the president had to hurry if he wanted to establish it before his impending retirement and against the doubts within the OAW.

Competition tender process

What materials were delivered to the architects who were invited to make proposals for the Old Aula renovation?

In the introduction of the brief, the President of the OAW made a few historical remarks. They stood in no connection to any other materials of the tender. The text of the brief was entirely focused on the definition of the renovation's scope and purpose, to the space allocation plan and the list of specifications, as well as to the procedure of the competition. Among all textual and visual representations, the main effort, also in terms of costs, was put into the production of survey plans: 2D floor plans, elevations and sections, as well as a digital 3D plan (Figures 2, 3 and 6). Eight colour photographs (Figure 7) were attached to the brief in small prints (12 × 9 cm). A CD contained the same photographs of the building; two aerial photographs of the Old University quarter; and a documentation of excavations in one section of the ground floor (Figure 9).

The eight participants of the international competition (from ten architects invited) were offered one official date for the visit of the building during which they could pose questions to the promoter, to the jury members and to a federal conservator. The resident participants could visit the building, which was not locked at daytime, more often. But whether they did so was a decision made by them.

The only historical or archaeological investigations of the Old Aula made before the competition and introduced into the tender were archaeological excavations under one of the four ground floor bays where it was intended that a new basement should be excavated (Figure 9). No thorough stress analysis of the building and no building archaeological investigations were made at this stage. The Commission for Art History of the OAW was not invited to participate in the elaboration of the tender, although it organized a conference about the Jesuits in Vienna, that is, about the builders of the Old Aula, in the year of the competition (Karner and Telesko, 2003). A conservator was invited only to the jury as a consultant member. (In their function as executive officials, federal conservators must not be voting jury members, for this would be incompatible with the impartiality of their final decision whether the interventions of a project are acceptable.)

One reason for these omissions was the tentative character of the competition and its expeditious realization. It was pushed through by the President of the OAW together with the head of its building department, Helmut Schuch. The tender was elaborated by the planning office ‘forschung planung beratung’, which was working in the fields of space planning, and ecological and energy concepts, but had no specific experience with historical buildings.

After 15 years of unrealized plans and some unconvincing pre-projects for the Gallery of Research and the according use of the Old Aula, the competition was an experiment. It was easier to accomplish with few participants and should be brought to an end quickly. Only after the competition did the project make a sudden and surprising move toward realization. In an interview, Schuch reflected on the process with the lapidary remark: ‘more luck than planning’. The entries of the competition (Hiesmayr, 2001) made the project seem feasible; and the winner of the competition, Rudolf Prohazka, was commissioned to develop construction plans further.

In a discussion Gerhard Lindner, an architect very experienced in well-prepared restoration and renovation projects, defended this rapid promotion of the project (in which he had not been involved):

That was the case in the Old Aula renovation: When the BHOE entered the project as the representative of the owner and builder, it commissioned a restorer who made surface investigations on his own and commissioned a subcontractor for building archaeological soundings. The reports were delivered when the architect was preparing the submission for the building permit. In consequence, one main conduit of the ventilation system had to be relocated – causing planning costs that could have been spared. However, the greater loss was that the knowledge produced by the investigations could not benefit the competition and the early planning phase.

The under-representation of the old building in the tender cannot be sufficiently explained by the experimental character and rapid speed of the competition. In spite of time pressures, the substantive effort of a digital 3D survey was made; and the jury members discussed further options about how the old building could be presented. Like the planning office, they were not chosen according to their experience with renovations, with the exception of the Chairman, Ernst Hiesmayr, who had been engaged in projects and discussion of conservation (Hiesmayr, 1967). One option discussed in the jury was the production of a scale model. Hiesmayr promoted this idea with an argument that could have been made by a conservator: that digital plans create a seductive opportunity for light-minded interventions (implying that in the guise of a scale model the old building would better resist light-minded interventions). But the idea was abandoned because producing ten samples of a model capable of being disassembled, which alone would have been useful for the design process, was too expensive.

This type of discussion indicates a situation that is confirmed by more general investigation: that there are few guidelines or agreed-upon habits of how to introduce an existing and historically esteemed building into a design process; and that the kind of under-representation of the old building observed in the Old Aula renovation is far from being unusual in the planning practice of renovations. In an interview, Schuch thus concluded the discussion of this issue: ‘We did prepare the tender according to our experience with new buildings’.

Who introduces old buildings into the tender?

The first question must be: Who usually elaborates the tender and who commissions this person?

The client (mostly the owner, his representative, or eventually the user) is always the first to act and to commission. Even institutions specialized in the management of old buildings – like the BHOE, which is in charge of historical buildings in public possession and explicitly defines its role as a ‘cultural mission’ – do not elaborate their tenders themselves.

The BHOE usually commissions preliminary studies (e.g. building archaeological investigations), the results of which are added to the tender. Less experienced builders often think that simple survey plans (with a low degree of exactness) suffice; and at the beginning of a project they only get the advice they seek. The Federal Office for the Care of Monuments does not intervene on its own initiative, which would be understood as intrusion, but provides advice upon request. With an institution such as the BHOE it is in constant informal contact.

The brief is usually written independently of preliminary studies by an architectural office. For public commissions it is highly formalized according to the Austrian construction contract procedure: it defines the procedure of the competition1 and focuses mainly on the space allocation plan and the list of specifications – as did the brief of the Old Aula renovation, which was following the competition regulations of the Austrian Chamber of Architects. According to Roland Lehner, a high official of the BHOE, the criteria for selecting the entrants (defined in the first phase of a two-phase competition) are very important: they can also require experience of the entrants with historical or listed buildings with specific types of buildings and construction materials, or previous collaboration with federal conservators and restorers. But the brief itself is not considered the place for the representation of the historical building and for its specification as a task of conservation.

The main reason for that is a very simple demarcation of professional disciplines: architects define the requirements for the new design; conservators and archaeologists define the old building. In the context of all decisions and choices that have to be made at the beginning of a renovation project, the tender is underestimated as a means of representing the old building. Lehner explained that the builders need experienced architects for three different tasks that exclude one another by definition and law: for the elaboration of the tender, in the jury, and as entrants. The first and second are usually chosen among regional residents, so the choice is restricted. For the elaboration of the tender the BHOE seeks architects who are foremost experienced in the execution of competitions. Experience in renovation projects and understanding of history is secondary.

The tender and the period of its elaboration are the most important moments of the old building's introduction into the renovation design. Except for the basic decisions concerning the use of the building, the design process has not yet started. At any rate, survey plans have to be prepared; and the architects will study the potential and overall profile of the extant building most intensely during the early, conceptual design that determines the basic decisions. Information communicated about the old building at tender stage will affect all entries. Information activated later will only be for the benefit of the winning project.

However, this is true not only for the entrants, but also for the jury of the competition and for the conservators: exact and well-presented information about the old building is very important at this particular moment. The more comprehensive and precise the archaeological investigations of foundations, walls and surfaces (plasters) by exact measurements (including deformations) and by soundings, the clearer the conservators can specify which parts of the building must not undergo any interventions; which need structural repair; and which can be changed more radically. (In the case of the Old Aula this was largely done based on archival evidence, allowing more interventions in parts which had been reconstructed after the Second World War.) The Federal Office for the Care of Monuments is fully conscious of that and uses the largest part of financial support of restoration and renovation projects for building archaeological investigations. A conservation specification also has importance for the future builders, as interruptions of the construction process due to unexpected findings or damage are very disturbing and costly. (However, preliminary investigations can only reduce the probability of such surprises, not exclude them.) Juries of architectural competitions, again, have to evaluate and judge the entries in a short time and having strategic conservation information would assist them in their deliberations.

Plans as boundary objects

Survey plans can serve as very useful boundary objects, according to the type Star and Griesemer (1989, p. 410) labelled ‘coincident boundaries’. All information about the history and state of the old building that is inscribed in the survey plans can easily be activated by superimposition, since the entrants necessarily rely on the same plans to inscribe their renovation design as the building archaeologists to inscribe all data about history and present state of conservation. It is sufficient to keep one scale. If the information about the old building is abundant and heterogeneous in nature, it can be layered on multiple transparent fabrics. These can be put on the entrants' plans to show immediately in which way they have integrated the old buildings' qualities into the renovation design.

This procedure is a very literal realization of what Fujimura (1987) had described as alignment of various windows which make a technical problem ‘doable’. The superimposed plans make a renovation doable by coordinating efficiently the conservational needs with the planning needs. The coordination serves the architects, defining clearly their space of action; and it serves the conservators to underline their professional authority by putting their claims on ‘hard science’.

Building archaeology currently produces the most important images of old buildings that ought to be renovated. It is efficient as a boundary discipline that has elaborated means of representation that translate historical expertise and conservators' claims into architectural visual language. More precisely, for an architect who is able and willing to interpret the historically inscribed survey plans for their own sake, these plans can set free a genuine cognitive power which really entwines historical analysis and design thinking. For example, building phase plans can make visible a historical pattern of structural development – and enable the architect to develop his own design as a continuation of this diachronic pattern (Cramer, 1993). For this half-analytical, half-creative reading – Cramer calls it ‘analytical design’ – it is decisive that the ‘reader’ of the plan has an understanding of two disciplines. Hence, in this case the plan does not operate as a boundary object in the sense of translating between two disciplines. When functioning as a boundary object between conservators and architects, such a plan will first facilitate communication and mutual understanding. Only in the best case will a shared reading of the plans by conservator and designing architect succeed to fuse historical analysis and creative design as intimately as one person that fully possesses both competencies may do.

Mostly, the historically inscribed plans are not at the core of any cognitive act, neither of the conservators, nor of the designing architects. The historical meanings they supposedly ‘transport’ instead reside silently behind their visual clarity. The danger inherent in such representational practice is a misleading technification and scientification of the old building whose historical appraisal has actually nothing to do with ‘hard science’. It is based on expertise (a 150-year-old tradition of Art History as an academic discipline), on the conservators' professional experience and knowledge; but the ascription of value to an old building cannot be verified or falsified by any kind of experimental proof. The building archaeologists can prove by scientific experiment and representation that a part of the building is from the 17th century; but this fact does not create historical value. In a similar sense, Mader (1993, p. 31) calls building archaeology an ‘ancillary science of conservation’. He thereby indicates the danger of grounding restoration works on damage surveys alone and insists on the necessity to ‘integrate them in conservationist knowledge and working principles’ (Mader, 1993, p. 33).

Behind the building archaeologists' clearly defined images are the narrations and the more fragile and constantly evolving arguments of art-historical hermeneutics and of their aesthetic judgement. If those are put too far in the forefront in the renovation design process, the danger is that the lines of permission and prohibition that define the space of action for the new design will be blurred or confused. But if they are hidden too far behind the ‘objectivity’ of archaeological plans, these become devoid of the values and meanings which they ought to represent and safeguard.

Plans are insufficient historical information

How can the ‘historical, artistic or cultural value’ of a building (to quote the central definition of ‘cultural heritage’ in the Austrian and all German laws for protection and preservation of ancient monuments) be communicated? It has been argued that plans are insufficient for this purpose. The additional components of ‘story telling’ and an invitation to aesthetic contemplation and analysis are needed. These components should be provided in the tender documentation and the presentation of the building in the context of the competition.

Story telling is at the core of historical and art-historical practice, from academic hermeneutical writing to guided tours. The verbal account is indispensable for the constitution of historical meaning. Hence, a chapter of the brief should be reserved for a historical account, which must at least refer to the most important historical data contained in the building phase plans and to the sections of the plans which are signalled as historically valuable or must not have any intervention. To make sense, this account will probably have to be connected by some kind of continuous historical narration and argument. In the brevity required of the brief it will not be comprehensive, but it can hint at the stream of knowledge by which it is fed.

Aesthetic contemplation and analysis is a practice that art historians and architects share as their symbolic engagement. Although their aesthetic interests in the old building may differ because of the different roles they play, it is on this common ground that the conservators can win the architects' emotion-based engagement for the old building, which will motivate them to elaborate their design with creative flexibility out of the old building. (In an interview, the general conservator Eva-Maria Höhle strongly emphasized the importance of the architects' emotional motives towards the old building.)

Some part of the historical understanding of architecture is possible only in connection with archive-based knowledge. Still, no matter how analytically and systematically art-historical research proceeds, the immediate sensuous and emotional response to the artefacts is irreducible in its argument and judgement. Given their executive power and the need to produce judicially tenable arguments, conservators tend to disconnect their expertise from this phenomenal ground and ‘objectify’ it by reference to an art-historical canon and the factuality of their arguments.

Architectural manuals for renovation planning and practical conservation literature give clear indications concerning preliminary investigations of buildings' structure, materials and building techniques. Those written from a conservation perspective add more about building archaeological investigations and the importance of exact plans and an analytical documentation of single rooms by room data sheets (Meyer-Bohle, 1991; Petzet and Mader, 1993; Bülte and Rodemers, 1997; Thomas, 1998; Eckstein, 1999). However, the phenomenal and aesthetic qualities of the old building are not accounted for.

For the exploitation of this common ground of architects' and art historians' symbolic engagement, it is necessary to insist on the importance of visits of the building and the use of photography.

Displacement and abstraction of the existing building

In case of the Old Aula renovation, no building archaeological investigations were made during the preparatory phase of the competition. This limited the potential of the survey plans to function as boundary objects between an analytical, historical perspective on the one side and a preparation for the new design on the other. (The excavations on the ground floor were made earlier and were not aligned with the survey plans.)

The survey plan's provision of only the plain linear structure of the building's profiles without any further inscriptions excludes the overwhelming sensual density; but enables the architects to focus on main structural features and rethink the building's design by bringing the old and the new onto one level. It allows for easy manipulation and change, fast series building, and comparison as well as scaling up and down. In the digital plans, the lines that represent the existing building have the same consistency as those lines which the designers can draw and delete themselves. More poignantly, one can say that by such survey plans (Figures 2, 3 and 6) the building is transformed into a state ‘as if it did not exist’. They could equally refer to a destroyed, reconstructed or invented building. Certain distortions and asymmetries are the only clear trace of the building's actual existence (and the survey plans of the Old Aula are relatively exact). In other words, the existing building is brought to the same level of abstraction and displacement on which a new building is designed by an act of anticipation. In addition, it also shows features invisible on site, if the extant building is obstructed by additional walls or suspended ceilings not yet removed at tender stage – as was the case on the first floor of the Old Aula (Figure 5). But as a reduction to a linear structure, it provides very limited and very specific information about the old building.

Survey plans alone would be the most appropriate kind of representation, if the architect's task was to determine whether a renovation, an extension or an entirely new construction is the best solution for the fulfilment of a set of user requirements under the condition of a given building. However, when a listed building ought to be preserved and renovated, additional means of representation are needed.

It might be argued that architects have an ability to ‘seeing into’ the plans and thereby incorporate the qualities they had earlier experienced in and around the building's site. However, they can only ‘see-in’ as much as they have experienced before; and the Old Aula brief only encouraged a single hour visit on site. Many of the entrants, who were living far away, were actually content with this one hour. The representational style of the tender abetted the limited approach to the task of renovation.

Visiting the building

Visits have a cognitive potential for understanding the old building's qualities, which is similar to that of scale models for the design of new buildings (for the cognitive and perceptual capacities of scale models, see Yaneva, 2005). Three-dimensional models can be turned in one's hand; they can be looked at from all possible angles; and they can be looked into with the naked eye or through the optical device of a periscope (or ‘modelscope’) – to mention only those capacities which derive from their three-dimensionality. It is well known that many of the most renowned contemporary architects such as Rem Koolhaas or Frank Gehry work extensively with scale models.

If the scale model is acknowledged as such a rich source for the cognition of a future building; and if the concreteness of its handling and perception is an advantage toward 2D or 3D drawings, then it seems paradoxical for the access and entry to the existing old building to be seen as a lesser cognitive tool. It allows for moving through space and sensing the boundaries and openings of space in relation to one's own body. One can perceive materiality, weight, acoustics and the flow of light, varying under different conditions, and the interference of all these phenomena. A one-hour visit, as planned in the Old Aula competition, is inadequate time for a thorough reflection on the potentialities of the building.

In all design processes it is the iterative movement between abstract and material representations, between bigger and smaller, more and less detailed representations which sets free the maximum cognitive capacity of the planning materials (for scale models of varying dimensions see Yaneva, 2005; for engineering design, see Brereton, 2004).

If the architects' renovation solutions are to be comprehensively informed by the old building and emerge from it economically, then the existing building is the foremost and most inexhaustible source for such a design. Depending on the nature of the competition,2 the following actions may be mandatory or voluntary to facilitate an improved outcome:

• The brief should invite the entrants to frequent visits by fixing weekly or other regular dates; and the builder should obtain entrance to all rooms wherever possible (this is important when the building is still used by other than the future users).

• The organizer of the tender or the client can invite experts and stakeholders (user, owner, structural engineer, building archaeologist, conservator, art historian) to accompany the entrants and discuss their projects with them on site.

• The planners and conservation advisors can be invited to produce their own annotated drawings, photographs or films of the extant building.

Photographs

When the author asked about photographical efforts made for the tender of the Old Aula renovation, Helmut Schuch answered that he had thought of commissioning Margherita Spiluttini for a series of the whole building. (The famous Austrian architecture photographer had already made photographs of the former Jesuit theatre on another occasion.) But he never did so. Obviously, photographs were of minor importance among the expeditiously performed preparations for the tender. So finally a member of the planning office ‘forschung planung beratung’ produced a short series of photographs (Figure 7).

The quality of these pictures is not comparable with what technically well-prepared photographs of an experienced specialist can show, by controlling carefully the rendition of space and axial clarity, avoiding distorted lines of wide angles, and optimizing light and colour by long exposure times.

Photographs are the most fine-grained indexical type of pictures to be made of a building. They are mechanically produced imprints testifying the reality of the represented object; and they show a physical building with sensuous complexity and density from one local perspective. Therefore, they are specific reminders of the actual building, which cannot be substituted by plans. (The architect Gerhard Lindner indicated this mnemonic quality from his own experience.)

But photographs do not only provide particular visual information about the extant building. As projections on paper they are also ‘immutable mobiles’ and bring this type of sensual image into the architectural office, in order to be worked upon by the designer in the same way survey plans are. One can draw onto photographs by hand, cut and paste them like in classical paper montage, or elaborate them digitally. During the whole design work, which is based upon photographs, their indexicality and density serve as potent reminders of the physical building, as a discrete and already complete unit of its own. (Eva-Maria Höhle mentioned in an interview that she prefers photo montages to digital renderings as visual material for discussions, for they show much more material qualities – and thus encourage the architects to dwell more intensely on the encounter of old and new materials.) Although photographs cannot replace site visits, they can complement the survey plans. They are particularly relevant, when designers are living abroad and cannot visit the site so easily – as was the case in the international Old Aula competition.

Possibly there is also an interaction between intense experience of the building on site and the use of photography as a design tool, in the sense that the photographs' concrete perspective facilitates immediate projection of a design concept which had been envisaged on site. This could be a reason why two of the four Viennese entrants of the Old Aula competition included photo-montages. Non-resident offices also produced montages, but processed them in a way as to turn them into rather abstract rendering (Hiesmayr, 2001).

Rudolf Prohazka's montage shows the entrance toward the somewhat strange spatial situation on the south of the Old Aula (Figures 1, 6, 7 and 8). A kind of square is constituted by a very short dead-end street, which had been cut off by the erection of the 17th-century Jesuit University College. (This, for example, is a kind of historical information that should be contained in the brief. It was important to Prohazka, as he mentioned it in an interview out of his own initiative, but he had learned about it only after the competition.) The level of this square lies 1.4 m below ground floor level of the Old Aula. Prohazka's simple solution of a wide and flat staircase mastered in a stately manner the requirement of a new main entrance on this side of the building – a requirement, which was matched by the other entrants in surprisingly strange and ineffective ways. In the introduction to the publication of the competition this solution is the first argument of detail by which the jury substantiates its decision (Hiesmayr, 2001, p. 81). Prohazka stated, in the description of his project, that the monumental staircase was taking over a common motive of this neighbourhood. Since this argument was clearly based on the architect's familiarity with the urban context of the Old Aula, it reinforces the hypothesis that design conceptions that strongly rely on site experience can be visualized well in photo-montages.

Hence, the organizers of the tender should think of using and asking for photographs as follows:

• A professional series of photographs should be commissioned. The photographic series should be well aligned to the brief, concerning the most important requirements and crucial difficulties, both in terms of conservation and necessary alterations. Since they have a function completely different from published architecture photography, which usually gives an image ‘post festum’, the photographer should be told that the photographs are considered as active design material and not only visual information. These photographs must also not be mixed up with photographs that document the building's state of conservation (as those contained in room data sheets).

• Photographs should be delivered in large prints, which can easily be copied and drawn into, thus motivating the application of photographs in the design process – as a sensuously ‘dense’ medium through which the existing building exerts a stronger resistance against too easy design interventions.

• The brief can explicitly ‘welcome’ photo montages as part of the entries, but without further specification – encouraging, now retroactively, the use of photographs as design material.

• The brief can also ask for photo montages of specific situations, viewpoints or details that are already determined as crucial points in the brief. (In the Old Aula renovation the south entrance was such a crucial point in the specifications – but the brief did not ask for a special form of representation.) The organizers of the tender can use this as a device, added to the power of words, to direct the entrants' attention to a problem, whose prior importance they want to underline. Thereby, they produce one more type of image that can be compared and judged easily by the jury.

Conclusion

A case study of the renovation project of the Old Aula has shown how little systematically old buildings are represented in the tender of the competition. This applies for their historical meaning and value, and even more for their present appearance. Clients, who are professionally specialized in the management of historical buildings, commission building archaeological investigations and other preliminary studies. But these studies are not integrated with the other materials contained in the brief. How the brief defines the projected building – its specifications and its space allocation plan – and the procedure of the competition, is fully systemized and formalized (by the competition regulations of the Austrian Chamber of Architects and, for public projects, by the Austrian construction contract procedure). However, little attempt is made to present comprehensively the old building in all its aspects and to coordinate all types of representations.

Building archaeology elaborates survey plans as boundary objects between architects and conservators by inscribing the plans with information about the state of conservation and with historical data. Superimposition of historically inscribed plans and design plans facilitates the collaboration of conservators and architects and the work of the jury. Building archaeological plans have further cognitive potential for the development of new design based on the historical structure. However, there is a danger that the historically inscribed plans do not really translate historical understanding of the building, if this is not augmented by an additional narrative account.

Particularly neglected was the presentation of the existing building. The capacities of site visits and photography were discussed in detail: as a means of presenting the old building to competition entrants; as instruments to direct specifically the designers' attention to crucial points of the design task; as planning material; and as a material that can facilitate the jury's task of design evaluation and selection.

In conclusion, it is useful to return to the question: Who creates and elaborates the tender documents for the competition? Usually this is done by an architectural office that is chosen according to its experience with the competition procedure. However, if the task of elaborating the tender is understood as a comprehensive and systematic representation of the old building in all its aspects and in relationship to the projected renovation, this is an insufficient criterion. Three alternative possibilities are suggested:

• Instead of independently commissioning an architect for the brief, another professional for the creation of survey plans, building archaeologists or restorers for historical investigations, and maybe a professional photographer – the client should gather a team of participants who divide and systematically coordinate their materials and contents of representation. Especially professional clients who understand the specific needs and difficulties of their projects could proceed in that way.

• The same task of team building and coordination could be handed over to an architectural office. But this depends upon the office having specific capabilities in renovation planning and team building undertaken in collaboration with conservators and restorers.

• Building archaeology has been analysed as a boundary discipline in the trading zone of renovation design. Before their specialization, many building archaeologists were trained as architects; and many are still working as planning architects. Hence, they would be particularly well prepared for this task – provided they can also deal with its managerial requirements regarding the competition procedure. They could extend their professional capabilities to embrace this more comprehensive task, instead of remaining in their purely analytical position.

However, it is clear that in this phase of a project everything depends on the client.

To summarize, the comprehensive representation of the old building should be closer to the way new architectural design is presented. Perhaps a lower degree of visual rhetoric is needed, but the capacities and qualities of an old building equally need to be shown on all levels, with the specific addition of its history. This claim is more evident, as soon as conservation is understood as participating in the design of the built environment and not as its antagonistic position.