On a corner lot in any residential district, nothing shall be erected, placed, planted or allowed to grow in such a manner as to materially impede vision between a height of 2 1/2 and 10 feet above the center line grades of the intersecting streets in the area bounded by the street lines of such corner lots and a line joining points along said street lines 25 feet from the point of the intersection.

Notwithstanding other provisions of this chapter, fences, walls and hedges may be permitted in any required yard, subject to the following provisions:

Where, in any residential district, more than 50% of the residential frontage of any block has been improved at the time of passage of this chapter with the building having front yards of less depth than that required for the particular residential district, then the required front yard depth for such district may be decreased in such block to a depth not less than that of the majority of the existing buildings as a special exception by the Zoning Hearing Board.

No accessory building shall be erected in any required yard, except as specified in Part 8, § 27-804B, and no separate accessory building shall be erected within five feet of any other building.

In any district, more than one structure housing a permitted or permissible principal use may be erected on a single lot, provided that yard and other requirements of this chapter shall be met for each structure as though it were on an individual lot.

The height limitations contained in the Table of Height, Area and Bulk Regulations do not apply to spires, belfries, cupolas, antennas, water tanks, ventilators, chimneys or other appurtenances usually required to be placed above the roof level and not intended for human occupancy.

The minimum habitable floor area of a dwelling, rooming (boarding) or bachelor unit hereafter erected or converted shall be at least 150 square feet for the first occupant, at least 100 square feet of additional habitable floor area for each of the next three occupants and at least 75 square feet of additional floor area for each additional occupant.

Where permitted in Part 5, single-family dwellings or other uses may be converted into two or more housekeeping and/or bachelor or rooming (boarding) units, provided that the Zoning Hearing Board makes the findings required by § 27-1105, and that the Zoning Hearing Board makes further findings that:

Every building hereafter erected or moved shall be on a lot adjacent to a public street, and all structures shall be so located on lots as to provide safe and convenient access for servicing, fire protection and required off-street parking.

For purposes of these regulations, "major recreational equipment" is defined as including boat trailers, travel trailers, pickup campers or coaches (designed to be mounted on automotive vehicles), motorized dwellings, tent trailers and the like and cases or boxes used for transporting recreation equipment, whether occupied by such equipment or not. No major recreational equipment shall be parked or stored on any lot in a residential district except in a carport or enclosed building or behind that portion of a building facing the required rear yard. No such equipment shall be used for living, sleeping or housekeeping purposes when parked or stored on a residential lot or in any location not approved for such use.

Automotive vehicles or trailers of any kind or type without current license plates shall not be parked or stored on any residentially zoned property other than in completely enclosed buildings.

In all residential districts, no building nor any portion of a building may project into any required yard, except as provided for below:

A business or commercial activity administered or conducted as an accessory use which is clearly secondary to the use as a residential dwelling and which involves no customer, client or patient traffic, whether vehicular or pedestrian, pickup, delivery or removal functions to or from the premises, in excess of those normally associated with residential use. The business or commercial activity must satisfy the following requirements: