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glossary of historic preservation terms


Adaptive Reuse: Refers to the process of reusing an old site or building for a purpose other than which it was built or designed for.


Addition: New construction added to an existing building or structure.


Alteration: Any act or process requiring a building permit or demolition permit, or any act or process that changes one or more of the historic, cultural, architectural or archaeological features of an area, property, structure, site or object, including, but not limited to, the erection, construction, reconstruction or relocation of any property, structure or object, or any part of a property, structure or object, or land-altering activities.


Appropriate: Especially suitable or compatible.


Balance: An important quality that is easily upset by building alterations or additions that disrupt the symmetry of a building with ill-planned garages, porches or room additions.


Building: A building, such as a house, barn, church, hotel, or similar construction is created principally to shelter any form of human activity. “Building” may also be used to refer to a historically and functionally related unit, such as a courthouse and jail or a house and barn. Examples include: carriage house, church, courthouse, house, library, shed, stable, store, theater, train station, garage, detached kitchen, barn, or privy.


Certificate of Appropriateness: A certificate issued by a Commission indicating review and authorization of plans for alteration, construction, demolition or relocation of a landmark, or property, structure, site or object within a district.

Character (Community): Community character refers to the distinct identity of a place.  It is the collective impression of a neighborhood or town makes on residents and visitors.

Character (Historic): The character of a building, district or neighborhood refers to all those visual aspects and physical features that comprise the appearance of every historic building.  Character-defining elements include the overall shape of the building, its materials, craftsmanship, decorative details, interior spaces and features, as well as the various aspects of its site and environment. (National Park Service, Preservation Brief 17:1)

Compatible: In harmony with location, context, setting, and historic character.


Construction: The act of adding an addition to a structure or the erection of a new principal or accessory structure on a property or site that requires a building permit.


Contemporary: Reflecting characteristics of the current period. Contemporary denotes characteristics that illustrate that a building, structure, or detail was constructed in the present or recent past.


Context: Conceptual framework or physical surroundings for a building or site.

Contributing: A classification applied to an area, property, structure, site or object within a district signifying that it contributes generally to the qualities that give the district historic, cultural, architectural or archaeological significance as embodied in the criteria for designating a district. An area, property, structure, site or object can be contributing even if it has been altered, as long as it maintains the character defined for the district.

Contributing Resource: Any building, object, or structure which retains a high degree of integrity and adds to the historical integrity or architectural qualities that make an historic district significant. 


Demolition: Any act or process that destroys all or any part of an exterior wall, foundation, interior or exterior column or load-bearing wall of a landmark or a property, structure, site or object within a district.  


District: An identifiable area with definable boundaries designated as a “Historic District” and in which a significant number of the properties, structures, sites or objects have a high degree of historic, cultural, architectural or archaeological significance and integrity.


Directional Orientation: Compatibility of a structure with properties and structures to which it is visually related in its directional character, whether vertical or horizontal.

Eligible: To be eligible for listing in the National Register, a resource must meet at least one of the following criteria:

  • Is associated with events that have made a significant contribution to the broad patterns of our history (Criterion A).

  • Is associated with the lives of persons significant in our past (Criterion B).

  • Embodies the distinctive characteristics of a type, period or method of construction, or represents the work of a master, or possesses high artistic values, or represents a significant and distinguishable entity whose components may lack individual distinction (Criterion C).

  • Has yielded, or may be likely to yield, information important in history or prehistory (Criterion D).

A resource does not need to have ben identified previously either through listing or survey to be considered significant under CEQA.  Lead agencies have a responsibility to evaluate them against the California Register Criteria prior to making a finding as to a proposed project's impacts to historical resources (PRC Sec. 21084.1, 14 CCR Sec. 15064.5(3)).

Enlarge: To extend a building, structure, or resource beyond its existing footprint, usually through the construction of an addition or new exterior feature. 


Architectural Appearance: The architectural character and general composition of the exterior of a property, structure or object, visible from a public street or public way, including but not limited to the kind and texture of the building material and the type, design and character of all architectural details and elements, including, but not limited to, windows, doors, light fixtures, trim and signs.


Historic District: A Historic District is an area with definable boundaries where a considerable number of properties have been designated as having historic, cultural, architectural, or archaeological significance and integrity.


Historic District (Local): An area designated as a “historic district” by ordinance and which may contain, within definable geographic boundaries, landmarks and other structures that contribute to the overall historic or architectural characteristics of the district.


Historic District (National): An area designated as a “historic district” by listing on the National Register of Historic Places. National Register districts, like local districts, contain landmarks and other structures that contribute to the overall historic or architectural characteristics of the district.


Historic Integrity: The ability of a property to convey its significance; the retention of sufficient aspects of location, design, setting, workmanship, materials, feeling, or association for a property to convey its historic significance.


Historic Material: Material from which the building was originally built.


Historic Preservation: According to the National Historic Preservation Act, includes identification, evaluation, recordation, documentation, curation, acquisition, protection, management, rehabilitation, restoration, stabilization, maintenance, research, interpretation, conservation, and education and training regarding the foregoing activities or a combination of the foregoing activities.


Historic Significance: Determines why, where, and when a property is important. Historic significance is the importance of a property with regard to history, architecture, engineering, or the culture of a state, community, or nation. Integrity: Adherence to a high level of historical, architectural accuracy and relatively unchanged since originally constructed. The Secretary of Interior recognizes a property’s integrity through seven aspects or qualities: location, design, setting, materials, workmanship, feeling and association.


Landmark: A property, structure, site or object designated as a “landmark” that has a high degree of historic, cultural, architectural or archaeological significance. All such designations include the lot(s) of record associated with the structure or object designated as a landmark.


Listing: The formal entry of a property in the National Register of Historic Places; also referred to as registration.


Maintain: To keep in an existing state of preservation or repair.


Mitigation: The act of lessening a negative impact.


Mothball (Stabilization): Temporary measures to protect a building from the weather as well as to secure it from vandalism; the act or process of applying measures essential to the maintenance of a deteriorated building, establishing structural soundness.


National Register of Historic Places: The nation’s official list of buildings, sites, and districts that are important in our history or culture. Created by Congress in 1966 and administered by State Historic Preservation Officers.


Nomination: Official recommendation for listing a property or district on the National Register of Places or as a local landmark property or district.


Noncontributing: A designation applied to a property, structure, site or object within a district indicating that it is not a representation of the qualities that give the district historic, cultural, architectural or archaeological significance as embodied in the criteria for designating a district.


Object: Constructions that are primarily artistic in nature or are relatively small in scale.


Obscured: Covered, concealed, or hidden from view.


Period of Significance: The length of time when a property was associated with important events, activities, or person, or attained the characteristics that qualify it for National Register listing. Period of significance usually begins with a date when significant activities or events began giving the property its historic significance; this is often a date of construction.


Preservation: The act or process of applying measures necessary to sustain the existing form, integrity, and materials of an historic property. Preservation can include 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.


Primary Façade: The front elevation of a structure, usually facing a street and containing the main entrance.


Proportion: Refers to the ratio of one dimension to another. Generally we use the word to indicate the relationship between height and width of a door or window. The proportions of an entire building are often referred to in the context of scale, the relationship between the size of the building and the size of a person.


Project: Any alteration, construction, demolition or relocation of an area, property, structure, site or object.


Reconstruction: The act or process of depicting, by means of new construction, the form, features, and detailing of a non-surviving site, landscape, building, structure, or object for the purpose of replicating its original appearance.


Refurbish: To renovate, or make clean, fresh, or functional again through a process of major maintenance or minor repair.


Rehabilitation: The process of making possible a use for a property through repair, alterations, and additions while preserving those portions or features which convey its historical, cultural, or architectural values.


Remodel: To change a building without regard to its distinctive features or style. Often involves changing the appearance of a structure by removing or covering original details and substituting new materials and forms.


Renovate: To repair a structure and make it usable again. Although this word is widely accepted outside the preservation community, historic preservationists prefer to use the term “rehabilitate” since it incorporates careful retention of historic architectural, or cultural features.


Repair: Any change to an area, property, structure, site or object that is not alteration, construction, relocation or demolition.


Replication: Constructing a building so that it is an exact replica or imitation of an historic architectural style or period.


Restore: The act or process of accurately depicting the form, features, and character of a property as it appeared at a particular period of time by means of the removal of features from other periods in its history and reconstruction of missing features from the restoration period.


Retain: To keep secure and intact.  “Retain” and “maintain” describe the act of keeping an element, detail, or structure and continuing the same level of repair to aid in the preservation of elements, sites and structures.


Rhythm: Regular occurrence of elements or features such as spacing between buildings. On structures, the repetition of rooflines, siding treatment, window placement or any number of visual elements.


Scale: A term used to define the proportions of a building in relation to its surroundings or the proportional elements that demonstrate the size, materials and style of buildings.


Setback: The placement of a structure on a parcel in relationship to the lot lines and other elements such as the street and other buildings.


Significant: Having particularly important associations within the contexts of architecture, history and culture.


Site: The location of a significant event, a prehistoric or historic occupation or activity, or a building or structure, whether standing or ruined, or vanished, where the location itself possesses historic, cultural, or archeological value regardless of the value of any existing structure.


Solid to Void: A relationship involving the proportionate amount of solid wall area to the void areas created by windows, doors, gables or arches.


Stabilization: The act or process of applying measures to sustain the existing form, integrity and material of a building or structure, and the existing form and vegetative cover of a site.

Streetscape: The combination of building facades, sidewalks, street furniture, etc. that define the street.


Structure: Anything constructed or erected, the use of which requires, directly or indirectly, a permanent location on or in the ground, including without limitation buildings, garages, fences, gazebos, signs, billboards, antennas, satellite sending or receiving dishes, swimming pools, walks, walls, steps, sidewalks and works of art.


Style: A type of architecture distinguished by special characteristics of structure and ornament and often related in time; also a general quality of a distinctive character.


Visible from the Street: Able to be seen by a person walking on the public street, alleys or sidewalks on which a building is located. In the case of a building located on a corner lot, the street means both streets on which the building is located.


Walls of Continuity: Facades and other site structures such as masonry walls, fences and landscape masses that form cohesive walls of enclosure that demonstrate visual compatibility with properties and structures to which they are related.

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