The Standards are to be applied to historic places, which have been (or could be) recognized by an appropriate authority for their heritage value, i.e., for their aesthetic, historic, scientific, cultural, social or spiritual importance or significance for past, present, or future generations. Historic places can include archaeological sites with resources on or below ground or under water, such as battlefields or shipwrecks; landscapes of all types and sizes, with their related natural and built features, such as urban parks or Aboriginal sacred sites; buildings such as individual houses or entire urban districts; and engineering works of all materials, construction types and sizes such as bridges or mining headframes. The Standards can also be applied to new construction attached, adjacent or related to any of these resource types. They are to be applied to specific conservation projects in a reasonable manner, taking into consideration economic and technical feasibility.
Conservation in the context of these Standards refers to retaining the heritage value of historic places and extending their physical life. Retaining the heritage value of historic places is primarily ensured through interventions, i.e., any actions (or deliberate inactions) that have a physical effect on the tangible elements of a historic place that do not obscure, damage, or destroy character-defining elements. The latter consist of the materials, forms, location, spatial configurations, uses and cultural associations or meanings that contribute to the heritage value of the historic place.
It is useful to consider conservation under three distinct headings: Preservation, Rehabilitation and Restoration, while recognizing that a given conservation project will often include a combination of these activities.
Preservation involves protecting, maintaining and stabilizing the existing form, material and integrity of a historic place, or of an individual component, while protecting its heritage value. There are nine Standards relating to Preservation, and they must all be applied to a Preservation project.
Since protection, maintenance and stabilization are at the core of all conservation projects, all nine Preservation Standards must be applied to any conservation project.
Preservation should be considered as the primary treatment when (a) the historic place’s materials, features and spaces are essentially intact and thus convey the historic significance without extensive repair or replacement; (b) depiction during a particular period in its history is not appropriate; and (c) a continuing or new use does not require extensive alterations or additions. Preservation tends to be the most cautious of the conservation treatments and retains the most materials. It is therefore most appropriate when heritage values related to physical materials dominate. A plan for Preservation should be developed before work is undertaken.
Rehabilitation involves the sensitive adaptation of a historic place or of an individual component for a continuing or compatible contemporary use, while protecting its heritage value. This is achieved through repairs, alterations and/or additions.
Three Standards relate to Rehabilitation and all three must be applied to a Rehabilitation project, in addition to the nine Preservation Standards.
Rehabilitation should be considered as the primary treatment when (a) repair or replacement of deteriorated features is necessary; (b) alterations or additions to the historic place are planned for a new or continued use; and (c) its depiction during a particular period in its history is not appropriate. Rehabilitation can revitalize historical relationships and settings and is therefore most appropriate when heritage values related to the context of the historic place dominate. A plan for Rehabilitation should be developed before work begins.
Restoration involves revealing, recovering or representing the state of a historic place or of an individual component, as it appeared at a particular period in its history, as accurately as possible, while protecting its heritage value.
Two Standards relate to Restoration, both of which must be applied to a Restoration project, in addition to the nine Preservation Standards.
Restoration may be considered as the primary treatment when (a) the significance of a historic place during a particular period in its history significantly outweighs the potential loss of existing materials, features and spaces from other periods; (b) there is substantial physical and documentary or oral evidence to accurately carry out the work; and (c) contemporary alterations and additions are not planned. Restoration is most appropriate when strong associative or symbolic heritage values have been obscured and can be revealed through removals, repairs and replacements based on detailed historical evidence. Before the work begins, a particular period (i.e., the restoration period) must be selected and justified, and a plan for Restoration should be developed.
A word of caution is in order: the removal of materials, features and spaces can result in considerable change to a historic place. The Restoration plan must therefore include a thorough analysis of the heritage value of the existing historic place as part of the justification for this potentially damaging treatment.