Preservation

Preservation is a form of treatment applied to historic properties that focuses on the maintenance and repair of existing historic materials and retention of a property's form as it has evolved over time..

The revised Secretary of Interior's Standards for the Treatment of Historic Properties (codified in 36 CFR 67 for use in the Federal Historic Preservation Tax Incentives program) define preservation as "as the act or process of applying measures necessary to sustain the existing form, integrity, and materials of an historic property."

Other forms of treatment include restoration, rehabilitation, and reconstruction.