Fire walls shall extend from the foundation to a termination point at least 30 inches (762 mm) above both adjacent roofs.
- Steppe d buildings in accordance with Section 706.6.1.
- Two-hour fire-resistance-rated walls shall be permitted to terminate at the underside of the roof sheathing, deck or slab, provided:
- Openings in the roof shall not be located within 4 feet (1220 mm) of the fire wall.
- Each building shall be provided with not less than a Class B roof covering. >
- There are no openings in the roof within 4 feet (1220 mm) of the fire wall,i>
- The roof is covered with a minimum Class B roof covering, and
- Th e roof sheathing or deck is constructed of fire-retardant-treated wood for a distance of 4 feet (1220 mm) on both sides of the wall or the roof is protected with 5up>/8-inch (15.9 mm) Type X gypsum board directly beneath the underside of the roof sheathing or deck, supported by a minimum of 2-inch (51 mm) nominal ledgers attached to the sides of the roof framing members for a minimum distance of 4 feet (1220 mm) on both sides of the fire wall.
Where a fire wall serves as an exterior wall for a building and separates buildings having different roof levels, such wall shall terminate at a point not less than 30 inches (762 mm) above the lower roof level, provided the exterior wall for a height of 15 feet (4572 mm) above the lower roof is not less than 1-hour fire-resistance-rated construction from both sides with openings protected by fire assemblies having a fire protection rating of not less than 3/4 hour.
Exception: Where the fire wall terminates at the underside of the roof sheathing, deck or slab of the lower roof, provided:
- The lower roof assembly within 10 feet (3048 mm) of the wall has not less than a 1-hour fire-resistance rating and the entire length and span of supporting elements for the rated roof assembly has a fire-resistance rating of not less than 1 hour.
- Openings in the lower roof shall not be located within 10 feet (3048 mm) of the fire wall.
Where a fire wall serves as an interior wall for a building, and the roof on one side or both sides of the fire wall slopes toward the fire wall at a slope greater than two units vertical in 12 units horizontal (2:12), the fire wall shall extend to a height equal to the height of the roof located 4 feet (1219 mm) from the fire wall plus 30 inches (762 mm). In no case shall the extension of the fire wall be less than 30 inches (762 mm).