Conservation philosophy

The philosophies of repair

1 August 2016

Dr Alan Forster discusses how the outcome of an historic repair project can be influenced by subjectivity and differing philosophical perspectives

When assessing a deteriorating structure, two professionals may look at the same building and propose significantly different repairs. The final result of the project will be influenced by experience, philosophical perspectives and financial constraints. These feed into the selection of the technical repair interventions and therefore the building aesthetics.

This article investigates why repair projects often start at a subjective point and are prone to further divergence when building conservation philosophies inform technical fabric repair decisions.

The need for objectivity

The assessment of an historic building requiring repair should lead to an objective evaluation of condition. Visual surveys are a commonly adopted method of inspection as they are easy to execute, are relatively cheap and do not rely on specialist technical survey equipment. These surveys are invaluable especially when used in conjunction with supplementary techniques such as infrared thermography.

The objectivity of a visual survey may be variable, being a function of human evaluation and interpretation. Objective reporting supports the establishment of fabric repair strategies and broader asset management. If objective criteria are not used, the broad scope of condition surveys may make consistent and uniform reporting difficult.

Subjectivity in the condition survey

James Douglas defines 'condition survey' as 'a descriptive, snapshot assessment of a building'. A survey involves:

'inspection with recording of narrative, sometimes with detailed analysis and identification of defects and related causes to determine remedial works'.

There should be a consistent and logical process for the inspection, recording and reporting, and – as is highlighted in BS 7913 (2013) – comprehensive, meaningful checklists can help ensure consistent evaluation.

The broad scope of condition surveys, however, makes their rational production and uniformity of content difficult to ensure. This difficulty is exacerbated if the client communicates their objectives poorly to those providing the professional services. Survey subjectivity has been described by Ad Straub as:

'the practice of condition assessment by building inspectors yielding variable results due to subjective perceptions of inspectors. Surveyor variability is defined as the situation where two or more surveyors, evaluating the same building, arrive at very different survey decisions'.

The heirarchy of building diagnostics

However experienced the surveyor, they will have a subconscious investigative protocol in any survey. Douglas identifies a 'hierarchy of building diagnostics', which can be subdivided into three principle areas:

  • commissioning;
  • monitoring; and
  • investigative diagnostics - further subdivided into protocols, testing techniques and cognitive branches.

The broad scope of condition surveys makes their rational production and uniformity of content difficult to ensure

The cognitive branches reflect the investigator’s critical-thinking, problem-solving and decision-making processes and are all inherently subjective. Clearly, these reflect a building professional’s experience, influences and prejudices, and they affect the objectivity and accuracy of reporting. In terms of evaluating holistic building performance and technical repair options, the hierarchy of building diagnostics can help make explicit these subjectivities and thus identify the potential deficiencies of a survey. Limiting variation, 'condition survey on historic buildings should be performed by competent persons with knowledge of traditional materials, construction technologies and decay processes', and a focus on conservation accreditation is a means of demonstrating such competency (BS 7913, p.19).

More generally, a chartered building surveyor has already proved their expertise by understanding the core competency areas of practice, and this can provide a degree of uniformity between practitioners.

Decision-making approaches

A system of problem solving and decision making, in which hypotheses are generated, is used to assess methods of repair. BS 7913 (p.9) specifically refers to an expressed hypothesis system with 3 critical questions to evaluate the need for effective repair. These are:

  1. Where are we now?
  2. Where do we want to be?
  3. How do we get there?

The hypothesis generation and methodologies used should be proportionate to the scope of the works and the significance of the building in question. Clearly, anyone undertaking a survey devises hypotheses consciously or subconsciously, but the relevance of the questions asked and the suitability and accuracy of the chosen solution depends on the building inspector’s experience, education and ability to analyse evidence. Any diagnostic process must enable the investigator’s hypothesis to be confirmed or refuted. Standardisation may prove difficult, leading to variation in condition survey and proposed fabric repair.

Differing philosophies

BS 7913 (p.6) indicates that 'understanding the significance ofan historic building enables effective decision making about its future'. Repairs should be assessed before selection against both ethics and principles, which respectively set out the broader issues or key concepts, and offer the specific criteria on which conservation works should be based, as Technical Advice Note 8: The Historic Scotland Guide to International Charters (1997) explains (see Table 1).

Ethics Principles
  • Authenticity (non-distortion of evidence)
  • Integrity
  • Avoidance of conjecture (need for incontestable evidence)
  • Respect for age and historic patina
  • Respect for the contribution of all periods
  • Minimal (least) intervention (or conservative repair)
  • Legibility (honesty and distinguishability)
  • Materials and techniques (like-for-like materials)
  • Reversibility
  • Documentation (meticulous recording and documentation)
  • Sustainability

Table 1: Tenets of building conservation philosophy

In my 2010 article Building conservation philosophy for masonry repair: Part 1 ‘Ethics’, I emphasise that:

'it could be assumed that the importance associated with each of the ethics and principles will vary from person to person, depending on their perspective and what they perceive to be of greater value. It is obviously best to consider them as holistically as possible, while comparing and contrasting the individual concepts. A skewed focus or over-reliance on any one of the ethics or principles will lead to a selected repair that may be eminently suitable in one respect, but clearly fails in other aspects'.

Generally, conservation professionals can be broadly categorised in philosophical terms as purists, pragmatists or cynics, with each of these dispositions influencing their approaches to fabric repair.

Weighing up the approaches

In reality, attitudes and perspectives cannot be neatly compartmentalised and are in no way binary, so decisions may be influenced by any of the three views. Additionally, a professional who is philosophically cynical does not automatically recommend indefensible conservation. Any professional, whether conservation-orientated or not, should understand the performance requirements of buildings, repairing them with the most appropriate materials and techniques possible.

The possibility for divergence between approaches is considerable

Conversely, a purist is not simply a pedant who dogmatically and uncompromisingly applies philosophical tenets. Most purists would seem to derive their understanding of building conservation from a long scholarly tradition reacting to damage of historic buildings by, for instance, Victorian conjectural restoration.

Also, far from preserving a structure as an archaeological artefact or museum piece, a purist philosophical approach including distinguishable repair can, in many cases, be exceptionally progressive, incorporating bold contemporary design into an historic context. Purists may be orientated towards conservative repair and honesty (the repair should be distinguishable, as in images 1 and 2), but such overt philosophically driven interventions can be aesthetically controversial.

building conservation

Figure 1: Philosophically driven fabric repair of Cardiff Castle, Cardiff, where repair of flank walls with red sandstone masonry banding delineates new from original fabric

building conservation 2

Figure 2: Philosophically driven fabric repair, Neues Museum, Berlin

My view is that the application of honest repair can be acceptable, but that context is paramount in making the decision. Furthermore, sensitively applied, honest or obtrusive repairs can be quite visually appealing for many practitioners, telling the story of an evolving structure.

A conservative repair approach, characterised by legible, minimal intervention and good maintenance, may better achieve conservation objectives and simultaneously reduce project cost by not undertaking unnecessary or overzealous interventions. The aphorism ‘less is more’ encapsulates this approach.

It is also important to understand that there are no absolutes in conservative repair, only greater levels of defence for selected repairs. The first rule of conservation is that there should be 'no dogmatic rules … Each case must be considered on its own merits', as AR Powys explains in the 1929 piece 'Repair of Ancient Buildings' for the Society for the Protection of Ancient Buildings.

Building conservation 3

Figure 3: Decorative plaster scheme, where no attempt has been made at restoration

A pragmatist may be influenced by various philosophical perspectives, proposing both restoration and conservative repair. The distinctions between the two are often misunderstood but form the basis of defensive positions for repair strategies.

Restoration is defined in BS 7913 (1998, p.10) as:

'An alteration of a building, part of a building or artefact which has decayed, been lost or damaged or is thought to have been inappropriately repaired or altered in the past, the objective of which is to make it conform again to its design or appearance at a previous date […] A presumption against restoration is a hallmark of the British approach to building conservation. Restoration can diminish the authenticity and thus the historic value of a building'.

That said, restoration is deemed acceptable if the architectural analysis determines that restorative design interventions enhance the building’s integrity and support its significance.

Conservative repair is characterised in BS 7913 (1998, p.10). It says:

'A conservative approach to repair is fundamental to good conservation. This means that no building or part of a building should be repaired before such repair is strictly necessary or unless there is a good reason'.

Without a clear philosophical vision or a willingness to restore certain sections of a building, deciding to make other interventions distinguishable could potentially result in a lack of continuity. It may then become difficult to defend interventions, as decisions to adopt honest repair or restoration become somewhat muddled.

A cynic who has no regard to the philosophy may take an approach that leads to significant falsification of the historic record by ‘restoring’ a building without giving consideration to distinguishability. Meaningful consideration of the philosophical tenets should be fundamental to defensible building conservation.

The influence of philosophies on repair selection

The initial evaluation of the degree of deterioration and how objectively it is reported is clearly critical. This may be influenced by the inspector’s experience and risk-aversion, leading to potentially different interventions. Compounding this, the application of philosophical tenets would again lead to divergence. The aesthetic outcome of the project is a function of the choices made by the professional, so the possibility for divergence between approaches is considerable, as a result of the numerous stages that they must consciously or subconsciously navigate.

Conclusions: the divergent project

  1. The subjective nature of survey and determination of the degree of deterioration cannot readily enable an objective starting point. A lack of commonality in definition also createsambiguity. Clear communication and a shared language may reduce the chances of this.
  2. Use of systematic surveying approaches may enable a relative level of uniformity, but the building inspector’s experience and interpretation may still vary considerably.
  3. The professional’s experience will directly affect the technical repair strategy selected, but will diverge when the differing building conservation philosophies are applied. Any philosophy may be seen from the practitioner’s individual perspective.
  4. Project aesthetics and their defensiblity may be radically different depending on technical and philosophical understanding. This must be understood by those commissioning advice.

It is evident that a well-considered, methodical survey should be undertaken by a professional with specific expertise and knowledge of fabric repair. There should be meaningful discussions between stakeholders on the defensibility of the selected interventions and their aesthetic consequences. Justification of actions and the supporting decisions is important; what seems reprehensible is when no consideration is given to philosophical approaches.

Dr Alan M Forster is Associate Professor and Programme Director for the MSc/PgDip in Building Conservation (Technology & Management) at Heriot-Watt University, Edinburgh.

Further information

  • See: BS 7913 Guide to the conservation of historic buildings
  • Read the full version of this paper
  • Images © Dr AM Forster
  • This feature is taken from the RICS Building surveying journal (May/June 2016)