(A) Room sizes. Every dwelling unit shall contain at least the minimum room size in each habitable room as required by the State Residential Building Code.
(1) Every dwelling unit shall contain at least 150 square feet of habitable floor area for the first occupant, at least 100 square feet of additional habitable area for each of the next 3 occupants, and at least 75 square feet of additional habitable floor area for each additional occupant.
(2) In every dwelling unit and in every rooming unit, every room occupied for sleeping purposes by 1 occupant shall contain at least 70 square feet of floor area, and every room occupied for sleeping purposes by more than 1 occupant shall contain at least 50 square feet of floor area for each occupant 12 years of age and over and at least 35 square feet of floor area for each occupant under 12 years of age.
(B) Ceiling height. At least 1/2 of the floor area of every habitable room shall have a ceiling height of not less than 7 feet, 6 inches.
(C) Floor area calculation. Floor area shall be calculated on the basis of habitable room area. However, closet area and wall area within the dwelling unit may count for not more than 10% of the required habitable floor area. The floor area of any part of any room where the ceiling height is less than 4-1/2 feet shall not be considered as part of the floor area for the purpose of determining maximum permissible occupancy.
(D) Cellar. No cellar shall be used for living purposes.
(E) Basements. No basement shall be used for living purposes unless:
(1) The floor and walls are substantially watertight;
(2) The total window area, total openable window area and ceiling height are equal to those required for habitable rooms;
(3) The required minimum window area of every habitable room is entirely above the grade adjoining the window area, except where the window or windows face a stairwell, window well or accessway.
(1988 Code, § 4-30)