Conservation Principles
The following principles apply to buildings and artworks, and should guide conservators and conservation architects alike.
The maintenance, repair and usage of objects and buildings are all part of the wider context of conservation. Anyone responsible for churches and their furnishings, whether specialist or non-specialist, should be aware of the basic principles of modern conservation practice. These conservation principles guide the theory and practice of conservation and underlie the advice given in this website.
Conservation as Management of Change
The main aim of conservation is the preservation of our cultural heritage for future generations. Today, conservation is generally defined as the ‘management of change'. This definition recognises that all buildings and artworks change over time, whether by means of natural physical change, such as the building-up of a patina, or by deliberate action, such as additions, repair or damage. In many cases in the past, conservators attempted to recreate the original state, often by means of removing significant historical accretions. Today, such alterations are often recognised as being valuable in their own right and as evidence of the object's past history and usage.
Modern conservation does not inhibit appropriate change or prevent access. Rather, it attempts to reconcile the needs of the object or building with the needs of the people who use or visit it. For churches, this means that a careful balance has to be struck between the needs of the congregation, worship and mission on the one hand and, on the other, the requirements for the long-term preservation of the building or the object.
Churches are unusual among historic buildings in that so many are still used for their original purpose after a history of up to a thousand years or more. Naturally, during their history many changes have occurred and as the needs of the congregation change the building has to be adapted accordingly. But all decisions about change have to be fully informed and mindful of the building's significance.
Minimum Intervention and Maintenance
An important objective of conservation is to remove or obscure as little original material as possible. Likewise, the addition of new material should be justified and kept to the smallest possible amount. This principle of ‘minimum intervention' underpins all conservation work.
In order to reduce the frequency and extent of necessary repair interventions, it is vital to minimise the rate of decay and deterioration. This can only be achieved by implementing and exercising a regular and informed maintenance and care regime. Acting on William Morris's demand to "stave off decay by daily care" can prevent major damage whose repair can be expensive and difficult.
Preserve as Found
Architects and conservators no longer strive to restore the original, supposedly ‘authentic' appearance of buildings and artworks but instead aim to respect the appearance and historical state in which the architect or conservator first encountered them. This obviously excludes cases of serious damage and decay, when the conservator has to intervene in order to improve stability, and cases necessitating the removal of previous repairs which are damaging to the building or object. The principle of ‘preserve as found' is a natural consequence of minimum intervention and they should be seen in conjunction with one another and the other conservation principles.
Like for Like Repairs
Unfortunately, even measures of preventive conservation, i.e. maintenance and the control of environmental problems, cannot stop long-term deterioration. At some point, the architect or conservator may have to use remedial conservation techniques, such as stabilisation or the removal of old and deteriorated repairs.
Architects and conservators should strive to use only those materials and traditional techniques which were used originally. This will ensure not only aesthetic but also physical integrity and continuity. If this is not possible, only such materials and techniques should be used which are compatible with the original materials. Materials which have comparable physical characteristics to the original materials used will have no detrimental effect on the object or building. Thus, its life span will be prolonged. A prominent example of a damaging material is hard cement mortar which, where used for the repointing of historic stone or brick buildings, has caused considerable damage over the years. Today, lime mortar is recommended instead which interacts more sympathetically with the physical characteristics of stone and brick and enables the free movement of liquid moisture.
Reversibility
Any new additions to a building or object should be carefully considered. They might have a significant visual impact on the building or object and considerably alter its character. Future generations might want to return to the original appearance of the church building or object and any additions should therefore be reversible. Also, some materials used today could turn out to be damaging at a future date or could be superseded by a more preferable material. The same holds true for conservation techniques. Nobody can predict what technical advances will be made in the future and, therefore, there has to be an opportunity for the easy removal of additions. While reversibility is not always easy to achieve in repairs, it should certainly be the guiding principle for any new additions.
Recording
Alongside all of these principles one has to keep in mind the need for the careful documentation of all decisions made and work undertaken. Works should always be accompanied by a detailed description of the object's or building's condition before any interventions, the architect or conservator's diagnosis and decisions, the treatment undertaken, any findings during examination and treatment and the state of the object after the interventions. The documentation should also contain photographs taken before, during and after the treatment.
Such detailed records will inform future generations and prevent misunderstandings. Anything that needs to be removed, such as leading cames from a stained glass window, should be carefully recorded and safely stored. In addition to the recording, the interventions should be made in such a way that they are easily detectable as such - without being intrusive. These, together with meticulous records, will be of invaluable help to future generations who might approach the object or building from a different perspective and with further insights.
November 2007
Further Information
The Manifesto of the Society for the Protection of Ancient Buildings (SPAB) is available on the SPAB website.
