Treatment > Physical Intervention

Record of Decision (ROD) involving any physical intervention, along with all supporting records, must be reviewed and approved in advance of intervention.

When considering intervention (remediation), assess effect on features and systems.


Every aspect of the preservation process, and every treatment, entails varying degrees of intervention. In fact, each treatment — from "housekeeping" through new construction" — is listed in order of the increasing degree of intervention imposed on each treatment to the physical fabric. It is a quantitative listing, not qualitative, and does not presume that on treatment is "better" or "worse" (more or less "appropriate").

The qualifications for the appropriateness any treatment are constructed around a policy of "minimum intervention to the historic fabric" and based on criteria considered through the preservation process.

As an example, new construction might impose less intervention to the collection than, say, adaptive use — as physical changes to the interior of a historic structure may have a greater, negative impact on the fabric than an addition to the exterior.


"Minimum intervention and reversibility are stated as being the two basic principles that lie behind all conservation work."

"Preventive conservation is the ongoing activity of non-invasive actions taken to prevent damage to and minimize deterioration of museum objects."

Inskip, P and Cannell, D, Problems tn the Renewal of Services in Historic Buildings, Module 7, RICS Diploma in Building Conservation, The College of Estate Management, UK, 1991as cited in Bridger, Colin and Nichols, Justine. An Investigation into the Refurbishment Characteristics Encountered When Integrating Modern Building Services into Historic Buildings. Oxford Brookes University, Oxford. [Download as PDF format file.]

" Minimum intervention aims to preserve as much original material as possible, doing no more than is strictly necessary to guarantee the proper use, conservation and prolongation of the ‘life’ of the original fabric. Its aim is to protect the original elements not just appearance, by applying a proportionate response to any intervention.

"Reversibility originated in the field of paintings conservation, where it is still a major criterion in selecting of appropriate treatment. In buildings conservation reversibility is harder to achieve and in the conservation of archaeological sites, reversibility is harder still to gauge. Reversibility has more recently been replaced by principles of compatibility and retreatability: a more sustainable conservation strategy, at the same time, stressing the importance of maintenance regime.

"Compatibility requires that treatment materials do not have negative consequences, and retreatability requires that the present conservation treatment will not preclude or impede future treatments. These principles are more sustainable because they are more realistic and enable future treatments to take advantage of progress in scientific knowledge. Maintenance is implied: in other words it is acknowledged that the next treatment is not likely to be the last.

"These principles provide a framework for deciding on acceptable and unacceptable conservation interventions. Yet these principles are not static: they have evolved with time, partly as a consequence of the internal development of conservation as a profession, and partly in response to changes in the human perception of the world and in particular of the environment."

Education and Training Needs for the Conservation and Protection of Cultural Heritage: is it a case of 'one size fits all'?, Workshop 2 Key Note Presentation by May Cassar, Director of the Centre for Sustainable Heritage, University College London, Cultural Heritage Research: a pan-European Challenge, Cracow, 16-18 May 2002.

"The appropriate level of intervention can only be chosen after careful consideration of the merits of the following:

  1. cultural significance,
  2. condition and integrity of the fabric
  3. contextual value
  4. appropriate use of available physical, social and economic resources."

B. Framework, Appleton Charter for the Protection and Enhancement of the Built Environment, ICOMOS Canada, August 1983.

"Interpretation has to be based on authentic qualities of the object. And if we want to pass down the objects to posterity as true documents, we have to care very much for the original substance. The extent to which this is spared during particular operations in conservation will depend very much on interpretation, mostly that by the conservator."

Jedrzejewska, Hanna. Ethics in Conservation, Stockholm, 1976.

"Measures will be undertaken to prevent or reduce deterioration of original....[material]... by attempting to control the causes, without physical or chemical intervention. Only when certain criteria have been met, such as intrinsic value or cost effectiveness, will action be undertaken to treat and/or restore these records."

Sample Policy, ANLA Preservation Policies And Procedures Manual For Small Archives, Association of Newfoundland and Labrador Archives, 2000.

"Certain items in a collection are so significant that they warrant conservation attention. Conservation of such items is especially appropriate when the materials cannot withstand use — even careful use — without being damaged, when they are physically or chemically unstable, or when they have received inappropriate treatment in the past."

Paris, Jan. Choosing and Working with a Conservator, Technical Leaflet, Conservation Procedures, Section 6, Leaflet 9, North East Document Conservation Center, 1999.

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