THE SECRETARY OF THE INTERIOR'S STANDARDS FOR REHABILITATION

1. A property shall be used for its historic purpose or be placed in a new use
that requires minimal change to the defining characteristics of the building
and its site and environment.

2. The historic character of a property shall be retained and preserved.  The
removal of historic material or alteration of features and spaces that
characterize a property shall be avoided.

3. Each property shall be recognized as a physical record of its time, place,
and use.  Changes that create a false sense of historic development, such as
adding conjectural features or architectural elements from other buildings,
shall not be undertaken.

4. Most properties change over time; those changes that have acquired historic
significance in their own right shall be retained and preserved.

5. Distinctive features, finishes, and construction techniques or examples of
craftsmanship that characterize a property shall be preserved.

6. Deteriorated historic features shall be repaired rather than replaced.
Where the severity of deterioration requires replacement of a distinctive
feature, 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.

7. Chemical or physical treatments, such as sandblasting, that cause damage to
historic materials shall not be used.  The surface cleaning of structures, if
appropriate, shall be undertaken using the gentlest means possible.

8. Significant archaeological resources affected by a project shall be
protected and preserved.  If such resources must be disturbed, mitigation
measures shall be undertaken.

9. New additions, exterior alterations, or related new construction shall not
destroy historic materials that characterize the property.  The new work shall
be differentiated from the old and shall be compatible with the massing, size,
scale, and architectural features to protect the historic integrity of the
property and its environment.

10. New additions and adjacent or related new construction shall be undertaken
in such a manner that, if removed in the future, the essential form and
integrity of the historic property and its environment would be unimpaired.

The following excerpted from _Landmark Yellow Pages_, REHABILITATION
STANDARDS, Richard Wagner

"The standards are intended to create a strong framework for responsible
preservation practices, to be used in conjunction with the accompanying
guidelines for applying the standards.  The underlying concern of the
standards is the preservation of the significant historic and architectural
characteristics of a structure that is being rehabilitated."
"in addition to providing guidance to individual property owners as they plan
their rehabilitation work,, the standards are used by the Secretary of the
interior to determine whether a rehabilitation project qualifies as a
'certified rehabilitation' for federal tax benefits under the Economic
Recovery Tax Act of 1981.  They are also used to assist state and local
governments and individuals in planning and carrying out rehabilitation work
on historic buildings."
Technical Preservation Services, National Park Service, _Respectful
Rehabilitation: Answers to Your Questions About Old Buildings_, 1982.

The Secretary of the Interior's Standards for Rehabilitation were originally
published in 1977 and revised in 1990.  The standards compose one section in
the Secretary of the Interior's Standards for Historic Preservation Projects
and appear in Title 36 of the Code of Federal Regulations, Part 68, which
governs alterations to buildings listed in the National Register of Historic
Places.  The standards, which pertain to the exterior and interior of historic
buildings, deal with design, methods of construction, and materials.  They
also apply to sites, landscapes, and archaeological resources listed in the
register.

In addition to the standards, the Department of the Interior 'also issues
_Guidelines for Rehabilitating Historic Buildings_, which contains recommended
(and not recommended) treatments commonly used in restoration and
rehabilitation projects.

Since each proposed design and historic building and landscape is unique, the
standards are applied on a case-by-case basis, taking into account specific
economic and technical considerations.  The standards and the guidelines, in
addition to preserving and enhancing the architectural character of a building
and its site, present sound technical advice to help reduce future maintenance
problems.

FURTHER READING
The Secretary of the Interior's Standards for Rehabilitation.  Rev. ed.
Washington, D.C.: Preservation Assistance Division, U.S. Department of the
Interior, 1990.

The Secretary of the Interior's Standards for Rehabilitation and Guidelines
for Rehabilitation Historic Buildings.  W Brown Morton III and Gary L. Hume
1979.  Rev. ed.  Washington, D.C.: Technical Preservation Services, U. S
Department of the Interior, 1983.

Interpreting the Secretary of the Interior’s Standards for Rehabilitation.
Washington, D.C.: Technical Preservation Services, U.S. Department of the
Interior, 1980.  Sets and occasional bulletins.

Preservation Briefs Series.  Technical Preservation Services, U.S. Department
of the Interior.  Washington, D.C.: U.S. Government Printing Office, 1975.
(Can be picked up from John Leeke's website.)

Preservation Tech Notes.  Technical Preservation Services, U.S. Department of
the Interior.  Springfield, Va.: National Technical Information Service, 1985.