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Standards and Criteria for Architectural Design Reviewof Exterior Alterations to Historic Structures

Permit and Resource Management Department Banner 750

The Landmarks Commission will evaluate each application for architectural and design review according to the following standards and criteria and any applicable land use plans. These standards and criteria are intended to provide a frame of reference for the applicant as well as a method of review for the Landmarks Commission. These standards and criteria shall not be regarded as inflexible requirements nor are they intended to discourage creativity, invention, and innovation. The goal is to preserve the character of the structures undergoing design review, enhancing their value and economic life.

General Design Rules for Alterations

The following rules set forth criteria that should be followed in altering, remodeling, repairing, or adding to the exterior of an historic structure. In evaluating each application, the Landmarks Commission will consider the extent to which these criteria are met.  Deviations from these  rules shall not be permitted, except where there are special design conditions affecting the building or where it would be impractical to comply with these rules.


  • A structure shall not be made to look either younger or older than when it was built. All structures shall be recognized as products of their own time. Alterations to create an earlier appearance shall be discouraged.
  • A structure shall relate positively to its visual environment.  A facade shall harmonize with the neighboring buildings. The major elements of design of a house shall unify the structure with its surroundings.
  • If old and new design and/or materials are mixed, the original character or design of the structure shall be retained.  Changes that may have taken place in the course of time are evidence of the history and development of the structure and its environment.  These changes may have acquired significance in their own right, and this significance shall be recognized and respected.

Exterior Facade

  • As many original exterior materials shall be retained as is economically and/or functionally feasible.
  • Imitation materials or design elements for exterior walls shall be avoided whenever possible. Synthetic materials may be used discretely for maintenance purposes only. Types of materials that shall be avoided are asphalt and asbestos shingles or siding, aluminum siding, aluminum windows and doors, and aluminum awnings.


  • The roof shall be a neutral-toned material. Roofing is generally not considered to be part of the color scheme of the house except when it constitutes a major visual aspect of the structure, such as tile in colonial period, etc.


  • Windows shall be replaced only if rehabilitation of the existing material is not functionally feasible. New windows shall generally be of the same size, material, and type as the old ones. Metal awnings, metal sash windows, non-functional decorative shutters unless architecturally accurate, and other modern types of window treatment shall be avoided.


  • Original doors shall be retained. The size and/or location of doorways shall not be changed or relocated except for restoration to original condition. Door treatment not in keeping with the original architectural style and aluminum screens shall be avoided. In all cases, the original "arrangement and proportion of doors and windows" shall be retained.

Porches and Stairways

  • Front porches, entrance porticos, and exterior stairways which were part of the original design shall not be removed. Alterations and indiscriminate changes usually destroy the original design integrity and visual balance of a building facade. Original materials shall be retained, or architecturally accurate replacements shall be used in repairing or reconstructing porch posts and railings. Updating wooden porches with wrought iron or brick generally destroys visual harmony and shall be avoided. Enclosing of porches can be done harmoniously if the original shapes and sizes of the openings are respected.

Color Scheme

  • For an effective color scheme, use of more than five colors shall be avoided. Walls shall be one major color with two or three colors used in the trim. Wall colors shall be in harmony with the streetscape.  Bright colors shall be used sparingly, for accent, if at all.

Specific Design Rules for Alterations

Exterior alteration of structures shall substantially conform to the following standards:

  • Height: Structures shall respect the height and scale of neighboring buildings, particularly the adjacent structures, to maintain a street's unity. An added upper floor which raises the height of a structure above that of its neighbors is generally not permitted. However, it may be permitted if the addition is set back from the front facade of the structure so that it is not noticeable from the street. Structures may be raised (lifted) if harmonious with the building proportions and consistent with the surrounding structures in the neighborhood.
  • Spacing: Uniform spaces between buildings lend a rhythm and harmony to the streetscape when viewed in sequence. A side addition to a structure which changes the rhythm of a row of buildings shall not be permitted.
  • Materials and Texture: Renovations to a structure shall use existing dominant materials and textures within a streetscape and the original design character of the structure. For example, a brick stairway shall not be constructed within a row of wooden entrance stairs unless appropriate to the architectural style of the structure.
  • Color: Although no specific color palette is required, exterior colors used on a structure are to be submitted for review to assure that colors used contrast or blend harmoniously with neighboring structures. Extremely bright colors shall be avoided, particularly when used as the primary color of the walls.
  • Windows and Doors: If windows and doors are redone or altered, the existing proportions of the area of the openings to the area of the walls shall be retained.
  • Architectural Details: Fences, roofs, chimneys, cornices, windows, entrances, awnings, porches, garage doors, and other accouterments shall be appropriate to styles which are already part of the structure.
  • Significant Architectural Details: All architectural features specifically included in the description of the structure set forth in the adopted survey and evaluation of the structure shall be retained, except where alteration or removal is required by law, or where there is no feasible alternative to the proposed alteration or removal.
  • Signs: Signs must comply with all applicable County Ordinances. In addition, signs must be compatible with the architecture of the structure and shall never detract from the significance of the building or the Historic District.