Condo firewall

[patchitect]

IBC 2015, Type VB construction, un-sprinklered.

I'm rebuilding 4 condo units in a larger 1977 development that were lost to fire, and building to current Code. The units adjoin an existing building such that the gable ends overlap. According to Code, I believe this requires a 2 hour firewall, but I'm unsure how to address the roof condition. Do I require a parapet 30" above the roof, or can I terminate under the roof deck with Fire resistive roof construction 10 feet out from the adjoining walls?

Photo for reference: The building to be removed is the Boarded up one, and the building to remain is at right angles. The gable ends overlap,

 

[steveray]

Welcome from CT!

706.6 Vertical continuity. Fire walls shall extend from the
foundation to a termination point not less than 30 inches (762
mm) above both adjacent roofs.
Exceptions:
1. Stepped buildings in accordance with Section
706.6.1.
2. Two-hour fire-resistance-rated walls shall be permitted
to terminate at the underside of the roof sheathing,
deck or slab, provided:
2.1. The lower roof assembly within 4 feet
(1220 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.
2.2. Openings in the roof shall not be located
within 4 feet (1220 mm) of the fire wall.
2.3. Each building shall be provided with not
less than a Class B roof covering.
3. Walls shall be permitted to terminate at the underside
of noncombustible roof sheathing, deck or slabs
where both buildings are provided with not less than
a Class B roof covering. Openings in the roof shall
not be located within 4 feet (1220 mm) of the fire
wall.
4. In buildings of Type III, IV and V construction,
walls shall be permitted to terminate at the underside
of combustible roof sheathing or decks, provided:
4.1. There are no openings in the roof within 4
feet (1220 mm) of the fire wall,
4.2. The roof is covered with a minimum Class
B roof covering, and
4.3. The 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 5/8-
inch (15.9 mm) Type X gypsum board
directly beneath the underside of the roof
sheathing or deck, supported by not less
than 2-inch (51 mm) nominal ledgers
attached to the sides of the roof framing
members for a distance of not less than 4
feet (1220 mm) on both sides of the fire
wall.
5. In buildings designed in accordance with Section
510.2, fire walls located above the 3-hour horizontal
assembly required by Section 510.2, Item 1 shall be
permitted to extend from the top of this horizontal
assembly.
6. Buildings with sloped roofs in accordance with Section
706.6.2.

 

[RLGA]

Are you sure you need a fire wall and not a dwelling unit separation wall?

 

[patchitect]

Welcome from CT!

4. In buildings of Type III, IV and V construction,
walls shall be permitted to terminate at the underside
of combustible roof sheathing or decks, provided:
4.1. There are no openings in the roof within 4
feet (1220 mm) of the fire wall,
4.2. The roof is covered with a minimum Class
B roof covering, and
4.3. The 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 5/8-
inch (15.9 mm) Type X gypsum board
directly beneath the underside of the roof
sheathing or deck, supported by not less
than 2-inch (51 mm) nominal ledgers
attached to the sides of the roof framing
members for a distance of not less than 4
feet (1220 mm) on both sides of the fire
wall.

Oh goodness... I really need to keep reading sometimes. I stopped short of that section!

Thank you!!

 

[patchitect]

Are you sure you need a fire wall and not a dwelling unit separation wall?

 

[VictorSnair]

I see it's been a while, but I hope you still need some advice. Based on my understanding, a 2-hour fire-rated separation is typically required for buildings with a common wall. Regarding the roof condition, it would be great to consult with a licensed architect or engineer knowledgeable about local building codes and regulations. I even suggest advising ith professional when buying a property, as I did when I was buying a condo in pine grove. I hope this information helps, and good luck with your rebuilding project!