Present established building lines. Wherever there is an established building line which is greater or less than the minimum setback lines called for in any district in this chapter, all buildings newly erected or reconstructed shall be set back so that the front of said buildings shall be in line with the setback lines of the existing buildings on the street in the block.

Average setback of existing dwellings. No proposed one-family or two-family dwelling need have a setback greater than the average setback of the existing dwellings located within 200 feet on each side of said proposed dwelling, on the same side of the street and within the same block and the same zone.

Unroofed constructions. An unroofed surface or patio which is not more than one foot above ground level, or an arbor, open trellis, or flagpole, is permitted closer to a lot line than the required setback. Paved areas (other than such walks and driveways as are needed for access to the buildings on the lot) shall not project within 15 feet of a street line or four feet of any other lot line. An open fire escape, deck or unroofed porch or terrace which is more than one foot above ground level may project not more than six feet into a required rear setback.

Entries and porticos. A roofed-over but completely unenclosed projection in the nature of an entry or portico, not more than eight feet wide and extending not more than six feet out from the wall of the building, shall be exempt from the front setback requirement when the building otherwise complies with all other front setback restrictions of this chapter.

Permitted obstructions. Cornices or cantilevered roofs may project not more than three feet into a required setback. Belt courses, windowsills, and other ornamental features may project not more than six inches into a required setback.

Awning, canopy, cornice or eaves. An awning or movable canopy may project not more than six feet into a required setback; cornices or eaves may project not more than 18 inches into a required setback.

Fences.

Measurement. All required front setback depths shall be measured from the designated street line, front lot line or existing street line, whichever is a greater distance from the center line on the public street abutting the lot in question.

Front setbacks on narrow streets. On streets with less than a 50 foot right-of-way, the front setback shall be measured from the center line of the existing right-of-way, and 25 feet shall be added to the required minimum front setback.

Lots on other than a public street. Where lots are subdivided on other than a public street, the designated street line, for the purposes of front setback measurement, shall be parallel to, and 25 feet distant from, the center line of any access easement or right-of-way.

Structures permitted in front yards. The placing of ornamental fountains, gatehouses and other structures for security or traffic control purposes, of a nonhabitable type, may be permitted between the street line and the required minimum front setback line, upon approval of the Planning Board and the Design Review Board.

Through lots. On a through lot, front setbacks are required from all street lines.

Yards; setback requirements. On a corner lot, front yards are required on both street frontages, and one yard other than the front yards shall be deemed to be a rear yard and the other (or others) a side yard(s). The minimum setback requirements for each shall be complied with.

Obstruction to vision at street intersections. At all street intersections in all residence districts, and in all other districts requiring a front setback of 15 feet or more, no obstructions to vision (such as shrubbery, hedge, or other natural growth, a fence or wall) exceeding 30 inches in height above curb level shall be erected or maintained on any lot within the triangle formed by the street lines of such lot and a line drawn between points along such street lines 30 feet distant from their point of intersection (see Sketch B below), nor shall the limbs or foliage on any tree obstruct vision or be permitted to grow nearer to the ground than eight feet where such limbs or foliage overhangs or is over or upon land within the triangular area as shown in Sketch B.