How should we approach the repair of modern buildings, especially those originally conceived to have a short life span, or designed in anticipation of change? And who should be undertaking the ‘conservation’ work: conservators in the spirit of curatorial excellence or architects in the spirit of Modernism? Many of the basic tenets of a ‘traditional’ conservation approach simply aren’t directly transferable to this new range of patients.
Here, in my view, are 5 of the key challenges:
1. How to repair with minimal intervention (and to maximise retention of original fabric)
Unlike historic buildings, Modern building materials do not lend themselves to ‘conservative repair’. Poor quality of concrete, workmanship and detailing have led to problems which are extremely difficult to rectify ‘conservatively’. Modern buildings may also have inherent design flaws that accelerate the decay mechanisms and cannot simply be rectified through a minimal intervention. There is often therefore a need to approach the project in a mindset of ‘restoration’ rather than ‘repair’, or perhaps in the mindset of the original architect, rather than that of a repairing craftsman.
2. How to use materials honestly and without seeking to deceive
Respecting the nature and authenticity of original fabric means avoiding obscuring or devaluing it by falsely aging the appearance of new interventions. The aim is to add to the story of the building with repairs that are readable. In practice this is not difficult to achieve with materials like concrete as matching the original colour and surface quality is virtually impossible without reverting to the application of paints. With Modern architecture therefore, what is the role of ‘authenticity’? Should the actual ‘age’ of a building be apparent after a repair programme, or should it be made to look as good as the day it was built? With ongoing advances in construction techniques, a new dilemma emerges as to whether or not to take the opportunity to ‘finish off the job’ in the manner the architect may have originally wanted, by replacement and upgraded surfaces or components.
3. How to make interventions ‘reversible’
The principle of reversibility suggests that it should be possible to remove new interventions to restore the building to its original form. This applies to any changes to the building itself and to the artefacts within, including furniture, murals and tapestries. The synthetic nature of materials within modern buildings often makes adhering to the principal of ‘reversibility’ in their repair impossible. Many techniques rely on hard chemical set either to one material, or as part of a bond between two adjoining materials. Concrete, for example, relies on homogeneity between old and new fabric making reversibility impossible to achieve. Similar issues concern sealants, mastics, membrane roof coverings and glazing compounds, all of which often require complete replacement.
4. How to use ‘tried and tested materials
Matching materials affects the appearance and technical performance of a building. However, as with historic buildings, problems are often experienced when sourcing matches for original materials. Finding suitable bricks, tiles and glass blocks is extremely difficult, time consuming, and cost prohibitive when only small quantities are required in repair. However failure to secure exact matches can have particularly unfortunate aesthetic consequences. On technical grounds, historic buildings conservation generally seeks to employ ‘like for like’ materials in repair that will not disturb the weathering and ‘breathe-ability’ of the surrounding materials. This, however, is less critical in modern buildings that are typically hard, impermeable and designed to resist moisture. High performance concretes, stainless steel reinforcement, space-age polymer paints and high-tensile carbon fibre compounds are now available to both repair and improve.
5. How to ensure necessary changes are well designed and ‘of their time’
This principal addresses some of the more interesting issues relating to Modern buildings. Unlike historic buildings the ‘essence’ of the design (and the intent of their designers) is more tangibly appreciated and understood, and in some cases the original designer(s) may still be alive. When considering how we deal with impracticable details, technical incompatibilities, flaws in the original structural design, and owners’ desires for wholesale change in the use or performance of the building, how should we respond? Should the building evolve through the intervention of another designer, or should it remain as a statement of originality by its author – original imperfections and all? These critical decisions are faced by conservation architects all over the world. Due to the simplicity and clarity of the original design, it is fair to conclude that intervention without architectural integrity would be undesirable and intolerable