Part 1: Defining the terms

Editor's Note: Before getting into the standards for rehabilitation, you should understand how the terms preservation, rehabilitation, restoration and reconstruction are used by the Department of the Interior, author of the standards.

These definitions come from the National Park Service Web site, and are based on the Department of the Interior Standards and Guidelines for Historic Preservation.

The Definitions:

• Preservation places a premium on retaining all historic fabric through conservation, maintenance and repair. It reflects a building's continuum over time, through successive occupancies, and the respectful changes and alterations that are made.

• Rehabilitation emphasizes the retention and repair of historic materials, but more latitude is provided for replacement because it is assumed the property is more deteriorated prior to work.

Both preservation and rehabilitation standards focus on the historic materials and features, finishes, spaces, and spatial relationships that give a property its historic character.

• Restoration focuses on the retention of materials from the most significant time in a property's history, while permitting the removal of materials from other periods.

• Reconstruction establishes limited opportunities to re-create a non-surviving site, landscape, building, structure, or object in all new materials.

Why Rehabilitation?

The Standards for Rehabilitation (codified in 36 CFR 67 for use in the Federal Historic Preservation Tax Incentives program) address the most prevalent treatment -- rehabilitation.

Rehabilitation is defined as "the process of returning a property to a state of utility, through repair or alteration, which makes possible an efficient contemporary use while preserving those portions and features of the property which are significant to its historic, architectural, and cultural values."

The Standards for Rehabilitation have been widely used over the years--particularly to determine if work on an historic building qualifies as a certified rehabilitation for federal tax purposes. Federal agencies use the standards in preserving historic properties owned or controlled by the government. Finally, local and state historic district and planning commissions across the country have adopted the standards.

Do the standards apply to all buildings?

The standards apply to historic buildings of all materials, construction types, sizes, and occupancy and encompass the exterior and interior of the buildings. They also encompass related landscape features and the building's site and environment, as well as attached, adjacent, or related new construction.

To be certified for federal tax purposes, a rehabilitation project must be determined to be consistent with the historic character of the structure(s), and where applicable, the district in which it is located.

Are any alterations allowed?

As used by the Department of the Interior, the term rehabilitation assumes that at least some repair or alteration of the historic building will be needed for contemporary use. However, these repairs and alterations must not damage or destroy materials, features or finishes that are important in defining the building's historic character.

For example, certain treatments--if improperly applied--may cause or accelerate physical deterioration of the historic building. This can include using improper repointing or exterior masonry cleaning techniques, or introducing insulation that damages historic fabric.

In almost all of these situations, use of these materials and treatments will result in a project that does not meet the standards. Exterior additions that duplicate the form, material, and detailing of the structure to the extent that they compromise the historic character of the structure will fail to meet the standards.

Next: More about standards and guidelines