Preservation is the appropriate treatment when the project's objective is to retain the building as it currently exists. This means that not only the original historic materials and features will be preserved, but also later changes and additions to the original building. The expressed goal of the Standards for Preservation and Guidelines for Preserving Historic Buildings is to retain the building’s existing form, features, and materials. This may be as simple as maintaining existing materials and features or require more extensive repair. Therefore, protection, maintenance, and repair are emphasized while a replacement is minimized. When the property’s distinctive materials, features, and spaces are essentially intact and thus convey the historic significance without extensive repair or replacement; when depiction at a particular period is not appropriate; and when a continuing or new use does not require additions or extensive alterations, Preservation may be considered as a treatment. Prior to undertaking work, a documentation plan for Preservation should be developed.