Private Garages.

(1) 

Combined with Dwellings. When a garage is located beneath or attached to a dwelling, the provisions on frame construction as stated in sections 13.10 and 13.11 prevail. Floor and ceiling construction above the garage, when it is located beneath the building, shall be unpierced and shall have a fire resistance of one hour, based upon the standard specification for fire tests for materials and construction. The walls and partitions shall be of such construction as will meet the requirements of the one hour fire tests, as above specified. Openings from dwelling into garage shall be restricted to a single doorway. Such opening shall be protected by a door, metal clad on the garage side. Wooden casings or jambs exposed on the garage side shall be metal clad. When a doorway connects directly with a cellar or basement on the same or lower level, the door sill shall be raised at least one foot above the garage floor level, or the doorway shall lead into a vestibule from which a second door connects with the cellar or basement.

(2) 

Separated from Dwelling. Private garages of frame construction, not attached to or a part of frame dwellings, shall not be constructed more than one story in height, nor more than eighteen (18) feet in height, measured from the floor to the peak of a pitched roof. The walls may have studs spaced not more than two (2) feet, center to center, with a single plate at the bottom and a double plate at the top. Wood drop siding may be used for enclosure walls securely nailed with at least two (2) 7d box nails in each board on each stud, when four (4) inch boards are used and two (2) 8d common nails, when six (6) inch boards are used. The rafters in pitched roofs of such garages may be two (2) inches by four (4) inches, twenty-four (24) inches center to center.

(3) 

Masonry Construction.

(a) 

Permitted. Nothing in this section shall be construed to prohibit the erection of private garages of masonry construction.

(b) 

Fire Resistance. Private garages of masonry construction, when built in combination with dwellings, shall conform to the provisions of subsection (2) of this section, as regards fire resistance.

(c) 

Height and Rafter Requirements. Private garages of masonry construction, when not built in combination with dwellings, shall conform to the provisions of subsection (3) of this section, as regards height and roof rafter requirements.

(4) 

Floors. Garage floors shall be concrete or equally fire resistive and impervious material.