Standards and Guidelines

The Secretary of the Interior's Standards

The Secretary of the Interior’s Standards for the Treatment of Historic Properties were inspired by the International Restoration Charter, adopted at the Second International Congress of Architects and Specialists of Historic Buildings held in Venice, Italy in 1964. This resolution, also known as the Venice Charter, provided basic principles for the conservation of historic resources around the world. The development of the Venice Charter was an effort to treat historic resources not as unchangeable works of art but as important parts of our entire built environment. The National Park Service (NPS), on behalf of the Secretary of the Interior, developed Standards for the Treatment of Historic Properties in an effort to establish concepts and guide decisions regarding maintaining, repairing, and altering historic properties in the U.S.

Four Approaches to the Treatment of Historic Properties

The Standards are intended to aid the public in making sound historic preservation decisions. The Standards and associated Guidelines offer four distinct approaches to the treatment of historic properties: preservation, rehabilitation, restoration, and reconstruction.


Preservation involves the maintenance and repair of existing historical materials and retaining the property’s form as it changes over time.


Rehabilitation involves altering or adding to a historic property to meet continued or changing uses while at the same time retaining the historic character of the property. The Standards for Rehabilitation were the first standards developed by NPS and remain the most commonly applied.


Restoration involves depicting a historic property at a particular period in its history, and usually involves the removal of evidence of later time periods.


Reconstruction involves recreating missing or non-surviving portions of a historic property for interpretive purposes .

Choosing an Appropriate Treatment

Choosing the particular treatment depends on factors such as the property’s historical significance, physical condition, proposed use, building code requirements, and intended interpretation.

Historical Significance

Buildings designated as National Historic Landmarks for their exceptional significance in American history and many buildings individually listed in the National Register of Historic Places warrant Preservation or Restoration. Buildings contributing to the significance of a historic district but not individually listed in the National Register of Historic Places are often candidates for Rehabilitation projects.

Physical Condition

If distinctive materials, features, and spaces that convey the historical significance of the building are intact, then Preservation may be the most appropriate approach. However, if more extensive repairs are required, or if alterations or additions are required to change the use of a building, then Rehabilitation may be a more appropriate treatment for the building.

Proposed Use

Some historic buildings will continue to be used for their original purpose following a Preservation or Restoration project. During a Rehabilitation project, many historic buildings can be adapted for new uses without causing serious damage to their historic character. However, some historic properties that were originally designed for a specialized use, such as jails, grain silos, ice houses, cold-storage warehouses, and manufacturing facilities may be very difficult to adapt to a new use without major alterations that may result in the loss of historic character.

Building Code Requirements

Whether the project involves Preservation, Rehabilitation, Restoration, or Recreation, building code requirements must be taken into consideration during the project planning process. Poorly designed or hasty code-required work may result in irreversible damage to a building’s materials and historic character. Abatement of hazardous materials such as asbestos and lead also has the potential to cause irreparable harm to historic finishes, if not carefully executed. The installation of life safety upgrades, such as fire alarms, egress stairways, and fire suppression systems should be carefully planned to avoid damaging the features that define the historic character of the building. Alterations and new construction to meet accessibility requirements should also be designed to minimize loss of historic materials and changes to the overall appearance of the building.

Intended Interpretation

In situations where it is important to convey a certain period of history, such as a house museum that depicts the lives of farmers during the 1880s, a Preservation, Restoration, or Reconstruction project may be the most appropriate treatment for that site. However, a private, single-family historic house or commercial building that contributes to the significance of a historic district may be a candidate for Rehabilitation.

Program Requirements

Certain programs for historic properties mandate use of a particular treatment. The Texas Historic Courthouse Preservation Program funds Restoration of historic county courthouses. The 20% tax credit available under the Federal Historic Preservation Tax Incentives Program and the 25% tax credit under the Texas Historic Preservation Tax Credit Program require that work meet the Standards for Rehabilitation.

Applying the Standards

The Secretary of the Interior’s Standards for the Treatment of Historic Properties are generally advisory, but the Texas Historical Commission applies the Standards when performing project reviews under state and federal laws and programs for historic properties.