Preservation
Preservation means the act or process of applying measures necessary to sustain the existing form, integrity and materials of an historic property. Work, including preliminary measures to protect and stabilize the property, generally focuses upon the ongoing maintenance and repair of historic materials and features rather than extensive replacement and new construction. New exterior additions are not within the scope of this treatment; however, the limited and sensitive upgrading of mechanical, electrical and plumbing systems and other code-required work to make properties functional is appropriate within a preservation project.
Source
36 CFR § 68.2
Scoping language
The standards for the treatment of historic properties will be used by the National Park Service and State historic preservation officers and their staff members in planning, undertaking and supervising grant-assisted projects for preservation, rehabilitation, restoration and reconstruction. For the purposes of this part: