# Dormer Fire Separation



## Francis Vineyard (Nov 23, 2015)

2012 IRC (2009 Virginia amended) without sprinklers

Townhouses located on a single lot. Since there are no interior lot line between the townhouse dwelling units;

1. does Section R302.2.2 item #3 require 1-hr. construction of the entire gabled dormer walls

and

2. both dormer roof projections without parapets?

The front dormers project above the roof up to 4 ft. and the extended rear dormers project above the roof up to 7 ft. These dormer walls are located 40 inches from the common 2-hr. separation wall.

*FIRE SEPARATION DISTANCE. *The distance measured from the building face to one of the following:

1. To the closest interior _lot_ _line; _or

2. To the center line of a street, an alley or public way; or

3. To an imaginary line between two buildings on the _lot._

 The distance shall be measured at a right angle from the face of the wall.

*R302.2.2 Parapets. *Parapets constructed in accordance with Section R302.2.3 shall be constructed for _townhouses _as an extension of exterior walls or common walls in accordance with the following:

1. Where roof surfaces adjacent to the wall or walls are at the same elevation, the parapet shall extend not less than 30 inches (762 mm) above the roof surfaces.

2. Where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is not more than 30 inches (762 mm) above the lower roof, the parapet shall extend not less than 30 inches (762 mm) above the lower roof surface.

*Exception: *A parapet is not required in the two cases above when the roof is covered with a minimum class C roof covering, and the roof decking or sheathing is of noncombustible materials or _approved _fire-retardant-treated wood for a distance of 4 feet (1219 mm) on each side of the wall or walls, or one layer of 5/8-inch (15.9 mm) Type X gypsum board is installed directly beneath the roof decking or sheathing, supported by a minimum of nominal 2-inch (51 mm) ledgers attached to the sides of the roof framing members, for a minimum distance of 4 feet (1219 mm) on each side of the wall or walls.

3. A parapet is not required where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is more than 30 inches (762 mm) above the lower roof. The common wall construction from the lower roof to the underside of the higher roof deck shall have not less than a 1-hour fire-resistance rating. The wall shall be rated for exposure from both sides.


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## Francis Vineyard (Nov 23, 2015)

Upon further reflection it is implied that the fire separation imaginary line continues above the roof of the common separation wall?


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