The Commission shall apply certain principles, standards, and guidelines for review in addition to those contained in Article 2.78.220 A. and B. [Cambridge City Code] in considering applications for certificates of appropriateness, non-applicability or hardship.

A. Principles of Review

The Commission recognizes the capacity of certain properties in the District for additional development under applicable provision of the zoning code and affirms its consideration of proposed additions and alteration to such properties consistent with the terms of this order. The Commission seeks to achieve consensus determinations based on the available historical record, recommendations from members, alternates and staff, and comments from applicants and abutters and consistent with the terms of this order. The Commission affirms its role as a technical advisor to applicants on issues of conservation and preservation.

B. General Conservation Standards

All applications shall be considered in terms of the impact of the proposed new construction or alteration, relocation or demolition of an existing building on the District as a whole, and in addition with regard to the potential adverse effects of the proposed construction, alteration, relocation or demolition on the surrounding properties and on the immediate streetscape. General conservation standards shall be to:

Conserve the historic development patterns of the neighborhood, including its green space, open vistas, generous setbacks, and predominately low density lot coverage;

Enhance the pedestrian’s visual enjoyment of the neighborhood’s buildings, landscapes and structures;

Protect structures listed on or determined eligible for listing on the National Register of Historic Places;

Encourage the preservation of the neighborhood’s buildings, landscapes, and structures;

Maintain the diversity of the neighborhood’s architectural styles.

C. Conservation Guidelines for Avon Hill

The following guidelines establish the conservation principles to be encouraged within any given application.

Infill Construction and Additions: In the A-2 zone, infill construction (including accessory buildings) and additions shall not cause total lot coverage to exceed 30%; in the B and C-1 zones, infill construction and additions should not cause total lot coverage to exceed 40%. In addition to considering streetscape impacts of infill construction and additions, vistas into and through the site from surrounding public ways should be conserved. Impacts on significant landscape features and mature plantings should be minimized. Additions should be compatible with the architectural character of the principal building and its surroundings, should be sited away from principal elevations, and should respect the cornice height of the original building.

Parking: Where parking between the principal front wall plane of a building and the street is proposed, curb cuts and square footage of paved area devoted to parking should be minimized. Paving in permeable materials is encouraged. Low fencing, low walls, and plant material to screen parking areas are encouraged.

Fences: Fences should be low and transparent to conserve vistas into and through properties and to enable the pedestrian’s visual access to the character of the district. The desire for enclosing private spaces should be balanced against the historically-open character of vistas in the district. Fences needed for privacy should enclose the minimum area necessary to achieve their intent and should leave a portion of the premises open to view from the public way. Where safe and appropriate, privacy fences should be set back behind a planting bed to avoid creating a vertical plane directly on the public way.