Preservation Principals

The Secretary of the Interior’s Standards for Rehabilitation are ten basic principles created to help preserve the distinctive character of historic buildings and sites, while allowing for reasonable change to meet new needs. The Standards (36 CFR Part 67) apply to historic buildings of all periods, styles, types, materials, and sizes. They apply to both the exterior and the interior of historic buildings. The Standards also encompass related landscape features and the building’s site and environment as well as attached, adjacent, or related new construction.

• Use for historic purpose or place in a new use that requires minimal change to the defining characteristics of the building.
• Avoid the removal of historic materials or alteration of features and spaces that characterize a property.
• Do not create a false sense of historical development by adding conjectural features or architectural elements from other buildings.
• Properties change over time; changes that have acquired historic significance in their own right shall be preserved.
• Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a property shall be preserved.
• Repair rather than replace deteriorated historic features. When replacement of a distinctive feature is required, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials.
• Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence.
• Chemical or physical treatments, such as sandblasting, that cause damage to historic materials shall not be used.
• New additions, exterior alterations, or related new construction shall not destroy historic materials that characterize the property. New work shall be differentiated from the old and shall be compatible in massing, size, scale, and architectural features.
• Design new additions and adjacent new construction in such a manner that if removed in the future, the essential form and integrity of the historic property would be unimpaired.