International Building Code Section 705

International Building Code 705.10

Joints. Joints made in or between fire walls shall comply
with Section 713.

International Building Code 705.1

General. Each portion of a building separated by one or
more fire walls that comply with the provisions of this section
shall be considered a separate building. The extent and location
of such fire walls shall provide a complete separation. Where a
fire wall also separates occupancies that are required to be separated
by a fire barrierwall, the most restrictive requirements of
each separation shall apply.

Party walls. Any wall located on a lot line between
adjacent buildings, which is used or adapted for joint service
between the two buildings, shall be constructed as a firewall
in accordance with Section 705. Party walls shall be constructed
without openings and shall create separate buildings.

International Building Code 705.1.1

Party walls. Any wall located on a lot line between
adjacent buildings, which is used or adapted for joint service
between the two buildings, shall be constructed as a firewall
in accordance with Section 705. Party walls shall be constructed
without openings and shall create separate buildings.

International Building Code 705.11

Ducts and air transfer openings. Ducts and air transfer
openings shall not penetrate fire walls.
Exception: Penetrations by ducts and air transfer openings
of fire walls that are not on a lot line shall be allowed provided
the penetrations comply with Sections 712 and 716.
The size and aggregate width of all openings shall not
exceed the limitations of Section 705.8.

International Building Code 705.2

Structural stability. Fire walls shall have sufficient
structural stability under fire conditions to allow collapse of
construction on either side without collapse of the wall for the
duration of time indicated by the required fire-resistance rating.

International Building Code 705.3

Materials. Fire walls shall be of any approved
noncombustible materials.
Exception: Buildings of Type V construction.

International Building Code 705.4

Fire-resistance rating. Firewalls shall have a fire-resistance
rating of not less than that required by Table 705.4.

International Building Code 705.5

Horizontal continuity. Fire walls shall be continuous
from exterior wall to exterior wall and shall extend at least 18
inches (457 mm)beyond the exterior surface of exteriorwalls.
Exceptions:
1. Fire walls shall be permitted to terminate at the interior
surface of combustible exterior sheathing or siding
provided the exterior wall has a fire-resistance
rating of at least 1 hour for a horizontal distance of at
least 4 feet (1220 mm) on both sides of the fire wall.
Openings within such exterior walls shall be protected
by opening protectives having a fire protection
rating of not less than 3/4 hour.
2. Fire walls shall be permitted to terminate at the interior
surface of noncombustible exterior sheathing,
exterior siding or other noncombustible exterior finishes
provided the sheathing, siding, or other exterior
noncombustible finish extends a horizontal distance
of at least 4 feet (1220 mm) on both sides of the fire
wall.
3. Fire walls shall be permitted to terminate at the interior
surface of noncombustible exterior sheathing
where the building on each side of the fire wall is protected
by an automatic sprinkler system installed in
accordance with Section 903.3.1.1 or 903.3.1.2.

Exterior walls. Where the fire wall intersects the
exterior walls, the fire-resistance rating for the exterior
walls on both sides of the fire wall shall have a 1-hour
fire-resistance rating with 3/4-hour opening protection
where opening protection is required. The fire-resistance
rating of the exterior wall shall extend a minimum of 4 feet
(1220 mm) on each side of the intersection of the firewall to
exterior wall. Exterior wall intersections at fire walls that
form an angle equal to or greater than 180 degrees (3.14 rad)
do not need exterior wall protection.

Horizontal projecting elements. Fire walls shall
extend to the outer edge of horizontal projecting elements
such as balconies, roof overhangs, canopies, marquees and
similar projections that are within 4 feet (1220 mm) of the
fire wall.
Exceptions:
1. Horizontal projecting elements without concealed
spaces, provided the exterior wall behind and
below the projecting element has not less than
1-hour fire-resistance-rated construction for a distance
not less than the depth of the projecting element
on both sides of the fire wall. Openings
within such exterior walls shall be protected by
opening protectives having a fire protection rating
of not less than 3/4 hour.
2. Noncombustible horizontal projecting elements
with concealed spaces, provided a minimum
1-hour fire-resistance-rated wall extends through
the concealed space. The projecting element shall
be separated from the building by a minimum of
1-hour fire-resistance-rated construction for a distance
on each side of the fire wall equal to the depth
of the projecting element. The wall is not required
to extend under the projecting element where the
building exterior wall is not less than 1-hour
fire-resistance rated for a distance on each side of
the fire wall equal to the depth of the projecting
element. Openings within such exterior walls shall
be protected by opening protectives having a fire
protection rating of not less than 3/4 hour.
3. For combustible horizontal projecting elements
with concealed spaces, the fire wall need only
extend through the concealed space to the outer
edges of the projecting elements. The exterior wall
behind and below the projecting element shall be
of not less than 1-hour fire-resistance-rated construction
for a distance not less than the depth of
the projecting elements on both sides of the fire
wall. Openings within such exterior walls shall be
protected by opening protectives having a
fire-protection rating of not less than 3/4 hour.

International Building Code 705.5.1

Exterior walls. Where the fire wall intersects the
exterior walls, the fire-resistance rating for the exterior
walls on both sides of the fire wall shall have a 1-hour
fire-resistance rating with 3/4-hour opening protection
where opening protection is required. The fire-resistance
rating of the exterior wall shall extend a minimum of 4 feet
(1220 mm) on each side of the intersection of the firewall to
exterior wall. Exterior wall intersections at fire walls that
form an angle equal to or greater than 180 degrees (3.14 rad)
do not need exterior wall protection.

International Building Code 705.5.2

Horizontal projecting elements. Fire walls shall
extend to the outer edge of horizontal projecting elements
such as balconies, roof overhangs, canopies, marquees and
similar projections that are within 4 feet (1220 mm) of the
fire wall.
Exceptions:
1. Horizontal projecting elements without concealed
spaces, provided the exterior wall behind and
below the projecting element has not less than
1-hour fire-resistance-rated construction for a distance
not less than the depth of the projecting element
on both sides of the fire wall. Openings
within such exterior walls shall be protected by
opening protectives having a fire protection rating
of not less than 3/4 hour.
2. Noncombustible horizontal projecting elements
with concealed spaces, provided a minimum
1-hour fire-resistance-rated wall extends through
the concealed space. The projecting element shall
be separated from the building by a minimum of
1-hour fire-resistance-rated construction for a distance
on each side of the fire wall equal to the depth
of the projecting element. The wall is not required
to extend under the projecting element where the
building exterior wall is not less than 1-hour
fire-resistance rated for a distance on each side of
the fire wall equal to the depth of the projecting
element. Openings within such exterior walls shall
be protected by opening protectives having a fire
protection rating of not less than 3/4 hour.
3. For combustible horizontal projecting elements
with concealed spaces, the fire wall need only
extend through the concealed space to the outer
edges of the projecting elements. The exterior wall
behind and below the projecting element shall be
of not less than 1-hour fire-resistance-rated construction
for a distance not less than the depth of
the projecting elements on both sides of the fire
wall. Openings within such exterior walls shall be
protected by opening protectives having a
fire-protection rating of not less than 3/4 hour.

International Building Code 705.6

Vertical continuity. Fire walls shall extend from the
foundation to a termination point at least 30 inches (762 mm)
above both adjacent roofs.
Exceptions:
1. Stepped buildings in accordance with Section
705.6.1.
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 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.
5. Buildings located above a parking garage designed in
accordance with Section 509.2 shall be permitted to
have the fire walls for the buildings located above the
parking garage extend from the horizontal separation
between the parking garage and the buildings.

Stepped buildings. 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 pro-
tected 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:
1. 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.
2. Openings in the lower roof shall not be located
within 10 feet (3048 mm) of the fire wall.

International Building Code 705.6.1

Stepped buildings. 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 pro-
tected 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:
1. 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.
2. Openings in the lower roof shall not be located
within 10 feet (3048 mm) of the fire wall.

International Building Code 705.7

Combustible framing in fire walls. Adjacent combustible
members entering into a concrete or masonry firewall from
opposite sides shall not have less than a 4-inch (102 mm) distance
between embedded ends. Where combustible members
frame into hollowwalls orwalls of hollowunits, hollowspaces
shall be solidly filled for the full thickness of the wall and for a
distance not less than 4 inches (102 mm) above, below and
between the structural members, with noncombustible materials
approved for fireblocking.

International Building Code 705.8

Openings. Each opening through a firewall shall be protected
in accordance with Section 715.4 and shall not exceed
120 square feet (11 m2). The aggregate width of openings at
any floor level shall not exceed 25 percent of the length of the
wall.
Exceptions:
1. Openings are not permitted in party walls constructed
in accordance with Section 705.1.1.
2. Openings shall not be limited to 120 square feet (11
m2) where both buildings are equipped throughout
with an automatic sprinkler system installed in accordance
with Section 903.3.1.1.

International Building Code 705.9

Penetrations. Penetrations of fire walls shall comply
with Section 712.