Restoration as a Treatment

Restoration is defined as the act or process of accurately depicting the form, features, and character of a property as it appeared at a particular period of time by means of the removal of features from other periods in its history and reconstruction of missing features from the restoration period. The limited and sensitive upgrading of mechanical, electrical, and plumbing systems and other code-required work to make properties functional is appropriate within a restoration project.


Standards for Preservation

Standards for Rehabilitation

Standards for Restoration

Standards for Reconstruction

History of the Standards

Guidelines for the Treatment
of Historic Properties

Guidelines for the Treatment
of Cultural Landscapes

Guidelines for Rehabilitating
Historic Buildings

Guidelines on Sustainability

View of a carved doorway through an arch at a Spanish Mission

Standards for Restoration

  1. A property will be used as it was historically or be given a new use which reflects the property's restoration period.
  2. Materials and features from the restoration period will be retained and preserved. The removal of materials or alteration of features, spaces, and spatial relationships that characterize the period will not be undertaken.
  3. Each property will be recognized as a physical record of its time, place, and use. Work needed to stabilize, consolidate and conserve materials and features from the restoration period will be physically and visually compatible, identifiable upon close inspection, and properly documented for future research.
  4. Materials, features, spaces, and finishes that characterize other historical periods will be documented prior to their alteration or removal.
  5. Distinctive materials, features, finishes, and construction techniques or examples of craftsmanship that characterize the restoration period will be preserved.
  6. Deteriorated features from the restoration period will be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature will match the old in design, color, texture, and, where possible, materials.
  7. Replacement of missing features from the restoration period will be substantiated by documentary and physical evidence. A false sense of history will not be created by adding conjectural features, features from other properties, or by combining features that never existed together historically.
  8. Chemical or physical treatments, if appropriate, will be undertaken using the gentlest means possible. Treatments that cause damage to historic materials will not be used.
  9. Archeological resources affected by a project will be protected and preserved in place. If such resources must be disturbed, mitigation measures will be undertaken.
  10. Designs that were never executed historically will not be constructed.

Restoration as a treatment

When the property's design, architectural, or historical significance during a particular period of time outweighs the potential loss of extant materials, features, spaces, and finishes that characterize other historical periods; when there is substantial physical and documentary evidence for the work; and when contemporary alterations and additions are not planned, Restoration may be considered as a treatment. Prior to undertaking work, a particular period of time, i.e., the restoration period, should be selected and justified, and a documentation plan for Restoration developed.

The Guidelines for the Treatment of Historic Properties illustrate the practical application of these treatment standards to historic properties. These Guidelines are also available in PDF format.

The Guidelines for the Treatment of Cultural Landscapes apply these treatment standards to historic cultural landscapes.