Zero Lot Line Dwellings

Zero lot line dwellings, also known as townhouses and patio homes, have yards that are part of the real estate and are owned by the dwelling owner. Each townhouse or patio home shall be considered a separate building, and separated by common walls meeting the requirements of the following.

Fire Separation Assembly/Common Wall
A common 2-hour masonry fire separation assembly is permitted for townhouses or patio homes if such walls do not contain plumbing or mechanical equipment, ducts or vents in the cavity of the common wall. Electrical installations are limited to electrical wire installed in raceways and electrical outlet boxes.

The common wall for townhouses or patio homes shall be continuous from the foundation to the underside of the roof sheathing, deck or slab, and shall extend the full length of the common wall.

A masonry wall meeting requirements for 2-hour fire rating is required. No combustible material may extend through the firewall. The firewall must extend out to the back of the fascia board when there is an overhang.

Parapets shall be provided for townhouses or patio homes when roof surfaces adjacent to the wall are at the same elevation. The parapet shall extend not less than 30 inches above the roof surfaces.

The exception to this rule is that a parapet is not required when the fire separation assembly terminates at the roof deck and the decking is of an approved, noncombustible, fire-rated material, or an approved, noncombustible, fire-rated material is applied for a distance of 4 feet on each side of the wall.