(1) Use Regulations. The specific uses permitted in this district shall be the erection, construction, alteration or use of buildings and/or land for:

(a) The uses permitted in "R-5A" Residential Districts, subject to all qualifications imposed on such uses;[25]

(b) Attached single-family and attached duplex dwellings in groups of not more than ten; provided, that each dwelling shall not be less than 18 feet in width.

(2) Area Regulations.

(a) Lot Width and Area. The minimum lot width shall be 18 feet, and the minimum lot area shall be 1,620 square feet; provided that the minimum lot width of the end dwelling of a permissible group shall be 30 feet, and the minimum lot area of the end dwelling shall be 2,700 square feet.

(b) Occupied Area. Not more than 50% of the lot area shall be occupied by buildings.

(c) Open Area. The open area shall be not less than 50% of the lot area and shall consist of at least the minimum front and rear yards in all cases, plus such other side yards or open courts, as shall be required to equal an area not less than the total area required.

(d) Building Set-back Line. The building set-back line shall be 15 feet from all street lines.

(e) Front Yards. The minimum depth of a front yard shall be the depth required between the street line and the building set-back line, as herein specified.

(f) Side Yards. When side yards are used, they shall have the following minimum widths:

(.1) Every detached single-family dwelling and every detached duplex dwelling shall have two side yards, neither of which shall be less than eight feet wide; provided, that every such dwelling located on a corner lot shall have the building set-back on the intersecting street adjudged a side yard (which shall not be less than the setback required), and the other or inside yard shall be not less than six feet wide (subject to exception for existing buildings, see § 14-104(12)).

(.2) Every semi-detached single-family dwelling and every semi-detached duplex dwelling shall have a side yard not less than eight feet wide; provided, that such a dwelling located on a corner lot shall have the building set-back on the intersecting street adjudged a side yard (which shall be not less than the set-back required).

(.3) Every detached dwelling which is the end unit of a permissible group shall have a side yard with a minimum average width of 12 feet; provided, however, that no portion of said yard shall be less than eight feet in width; and provided further, that such a dwelling located on a corner lot shall have the building set-back on the intersecting street adjudged a side yard (which shall not be less than the set-back required).

(.4) Every building other than a dwelling shall have two side yards neither of which shall be less than 8 feet wide (subject to exception for existing buildings, see § 14-104(12)).

(g) Courts.

(.1) Open courts not between wings of the same building shall be the same minimum width required for side yards, except in the case of attached dwellings, which shall have a required minimum width of five feet (subject to exception for existing buildings, see § 14-104(12)).

(.2) Open courts between wings of the same buildings and inner courts shall be governed by the provisions of § 14-231(1).

(h) Rear Yards.

(.1) The minimum depth of a rear yard shall be 20 feet for a single-family dwelling;

(.2) The minimum depth of a rear yard shall be 25 feet for a duplex dwelling; or for any building other than a dwelling.

(3) Height Regulations.

(a) The maximum height of a dwelling shall be 35 feet above the average ground level at the base of the building, but in no case over three stories.

(b) The permitted height of non-residential buildings shall be 35 feet, except that one foot of additional height may be added for each additional foot the building sets back from all lot lines; provided, however, that the maximum height of any such building shall be 60 feet (subject to the provisions of § 14-231(2)).

(4) Off-street Parking. See § 14-1400 of this Title.