Current through Vol. 42, No. 1, September 16, 2024
Chapter 7 of the IRC® 2018 is adopted with the following
modifications:
(1) Section 703.1
General. This section has been modified to clarify and add requirements for
direct applied exterior finish with water-resistive barrier installations. This
section has been modified to read: 703.1 General. Exterior walls shall provide
the building with a weather- resistive exterior wall envelope. The exterior
wall envelope shall include flashing as described in Section R703.4. Direct
Applied Exterior Finish Systems Cement Board based stucco finish and direct
applied masonry or stone shall comply with the following:
(A) Item 1. Direct applied masonry or stone
shall comply with Section R703.7.3 Water- resistive barriers and product
manufacture's installation specifications.
(B) Item 2. Cement Board Stucco Exterior
Finish Systems shall be installed per manufacturer installation instructions
and meet the minimum wall assembly details below. Products that make up the
finished wall system that consists of base coat, secondary coat, reinforcing
mesh and finish coat shall be of same manufacturer to ensure product/material
compatibility and performance.
(i) Item 2.1.
Approved Sheathing.
(ii) Item 2.2.
Base flashing at bottom of walls and roofs.
(iii) Item 2.3. Water resistant barrier equal
to or greater than 60-minute Grade D paper or ASTM D226.
(iv) Item 2.4. Approved Cement Board for wall
application base for exterior wall ASTM C1326.
(v) Item 2.5. Approved Cement Board Joint
Reinforcement Coat and Mesh.
(vi)
Item 2.6. Base Coat.
(vii) Item 2.7.
Reinforcing Mesh ASTM E2098(Alkaline Resistant).
(viii) Item 2.8. Second Base Coat.
(ix) Item 2.9. Finish Coat.
(x) Item 2.10. Other Design Considerations:
Separation distance from finish exterior grade must be 6 inches or greater.
Separation from roofs must be 1 inch or greater. Through wall flashing must be
provided at horizontal locations at dissimilar materials. Expansion joints, if
needed, shall comply with finish system manufacturer recommendations. Expansion
gaps are required around all windows, doors, or other dissimilar material
integrated in the wall and joints are required to be sealed.
(C) Exception: Log walls designed
and constructed in accordance with the provisions of ICC
400®.
(2) Section
R703.4 Flashing. This section has been modified to clarify that 6-mil
polyethylene sheeting is an approved corrosion-resistant flashing in certain
circumstances and to clarify flashing above doors is not required when the door
is covered by a minimum of 3 feet. This section has been modified to read:
R703.4 Flashing. Approved corrosion- resistant flashing shall be applied
shingle-fashion in a manner to prevent entry of water into the wall cavity or
penetration of water to the building structural framing components. 6-mil
polyethylene sheeting is an approved corrosion-resistant flashing when not
exposed to UV rays. Self-adhered membranes used as flashing shall comply with
AAMA 711. Fluid-applied membranes used as flashings in exterior walls shall
comply with AAMA 714. The flashing shall extend to the surface of the exterior
wall finish. Approved corrosion-resistant flashings shall be installed at the
following locations:
(A) Item 1. Exterior
window and door openings. Flashing at exterior window and door openings shall
extend to the surface of the exterior wall finish or to the water-resistive
barrier complying with Section R703.2 for subsequent drainage. Mechanically
attached flexible flashings shall comply with AAMA 712. Flashing at exterior
window and door openings shall be installed in accordance with one or more of
the following:
(i) Item 1.1. The fenestration
manufacturer's installation instructions and flashing instructions, or for
applications not addressed in the fenestration manufacturer's instructions in
accordance with the flashing manufacturer's instructions. Where flashing
instructions or details are not provided, flashing to be installed per 1.2,
1.3, 1.4 or, pan flashing shall be installed at the sill of exterior window and
door openings. Pan flashing shall be sealed or sloped in a such a manner as to
direct water to the surface of the exterior wall finish or to the
water-resistive barrier for subsequent drainage. Openings using pan flashing
shall incorporate flashing or protection at the head and sides.
(ii) Item 1.2. In accordance with the
flashing design or method of a registered design professional.
(iii) Item 1.3. In accordance with other
approved methods.
(iv) Item 1.4.
Flashing above doors are not required where the door is covered by a minimum of
3 feet.
(B) Item 2. At
the intersection of chimneys or other masonry construction with frame or stucco
walls, with projecting lips on both sides under stucco copings.
(C) Item 3. Under and at the ends of masonry,
wood or metal copings and sills.
(D) Item 4. Continuously above all projecting
wood trim.
(E) Item 5. Where
exterior porches, decks, or stairs attach to a wall or floor assembly of
wood-frame construction.
(F) Item
6. At wall and roof intersections.
(G) Item 7. At built-in gutters.
(3) Section 703.7.3
Water-resistive barriers. This section has been modified to clarify the
requirements for the water-resistive barrier, where applied over approved
sheathing to drain to the outer water-resistive barrier. This section has been
modified to read: 703.7.3 Water- resistive barriers. Water-resistive barriers
shall be installed as required in Section R703.2 and, where applied over
approved sheathing, shall include a water-resistive vapor-permeable barrier
with a performance at least equivalent to two layers of Grade D paper. The
individual layers shall be installed independently such that each layer
provides a separate continuous plane and any flashing, installed in accordance
with Section R703.4 and intended to drain to the outer water-resistive barrier.
Exception: Where the water-resistive barrier that is applied over wood-based
sheathing has a water resistance equal to or greater than that of 60 -minute
Grade D paper and is separated from the stucco by an intervening, sustainably
nonwater- absorbing layer or designed drainage space.
(4) Section R703.8 Anchored stone and masonry
veneer, general. This section has been modified to specify anchored stone walls
shall have an additional layer of No. 15 asphalt felt complying with ASTM D226
for Type I felt or other water-resistive barrier to provide a bond break
between the primary water-resistive barrier and the back side of the stone and
mortar. This section has been modified to read: R703.8 Anchored stone and
masonry veneer, general. Anchored stone and masonry veneer shall be installed
in accordance with this chapter, Table R703.3(1) and Figure R703.8. These
veneers installed over a backing of wood or cold-formed steel shall be limited
to the first story above grade plane and shall not exceed 5 inches (127 mm) in
thickness. See Section R602.10 for wall bracing requirements for masonry veneer
for wood-framed construction and Section R603.9.5 for wall bracing requirements
for masonry veneer for cold-formed steel and connections. Anchored stone walls
shall have an additional layer of No. 15 asphalt felt complying with ASTM D226
for Type I felt or other approved water-resistance barrier to provide a bond
break between the primary water-resistive barrier and the back side of stone or
mortar. Exceptions:
(A) Exception 1. For
buildings in Seismic Design Categories A, B, and C, exterior stone or masonry
veneer, as specified in Table R703.8(1) with a backing of wood or steel framing
shall be permitted to the height specified in Table R703.8(1) above a
noncombustible foundation.
(B)
Exception 2. For detached one- and two-family dwellings in Seismic Design
Categories D (subscript 0), D (subscript 1), and D (subscript 2), exterior
stone or masonry veneer, as specified in Table 703.8(2) with a backing of wood
framing shall be permitted to the height specified in Table 703.8(2) above a
noncombustible foundation.
(5) Figure R703.8 Typical Masonry Veneer Wall
Details. This figure has been modified to add footnotes "f" and "g" to the
footnote section and amend the figure heading to include a superscript "f" and
"g" to indicate the associated footnotes. This figure's footnotes have been
modified to read:
(A) Footnote "a" reads: "See
Sections R703.4, R703.8.5, and R703.8.6."
(B) Footnote "b" reads: "See Section R703.2
and R703.8.4."
(C) Footnote "c"
reads: "See Section R703.8.4. and Table R703.8.4.2."
(D) Footnote "d" reads: "See Section
R703.8.3."
(E) Footnote "e" reads:
"Figure R703.8 illustrates typical construction details for a masonry veneer
wall. For the actual mandatory requirements of this code, see the indicated
sections of text. Other details of masonry veneer wall construction shall be
permitted provided the requirements of the indicated sections of text are
met.
(F) Footnote "f" reads:
"Flashing to be done per Section R703.4, in accordance with a design from a
registered design professional or in accordance with other approved methods or
standard industry practices."
(G)
Footnote "g" reads: "Flashing depicted under sill and above windows are not
required with windows that have flanges for their primary attachment. Flange
type windows shall be counter flashed into the weather-resistant barrier or
installed per Section R703.4 and per window manufacturer's installation
instructions."
(6)
Figure R703.8.2.1 Exterior Masonry Veneer Support by Steel Angles. This figure
has been modified by adding a footnote to the figure. The figure heading has
been modified to have a superscript letter "a" to indicate a new footnote is
applicable. Footnote "a" has been added to read:
a. Flashing to be done per Section R703.4, in
accordance with a design from a registered design professional or other
approved methods as defined by the code for wall flashing.
(7) Figure R703.8.2.2 Exterior Masonry Veneer
Support by Roof Members. This figure has been modified by adding a footnote "a"
to the figure. The figure heading has been modified to have a superscript
letter "a" to indicate a new footnote is applicable. Footnote "a" has been
added to read:
a. Flashing to be done per
Section R703.4, in accordance with a design from a registered design
professional or other approved methods as defined by the code for wall
flashing.
(8) Section
R703.8.3.1 Allowable span. This section has been modified to provide guidance
to builders using, a typical for Oklahoma, lintel. This section has been
modified to read: R703.8.3.1 Allowable span. The allowable span shall not
exceed the values set forth in Table R703.8.3.1. Additionally, a 3 inches x 3
inches x 3/16 inch (76 mm x 76 mm x 4.8 mm) steel angle 6 feet (1829 mm) long
may be used to support 3 vertical feet (914 mm) of masonry veneer and a 3
inches x 3 inches x 3/16 inch (76 mm x 76 mm 4.8 mm) steel angle 5 feet (1524
mm) long may be used to support 4 1/4 vertical feet (1295 mm) of masonry
veneer.
(9) Section R703.9.1
Exterior insulation and finish systems (EIFS). This section has been modified
to clarify EFIS shall be installed in accordance with the same product
manufacturer's instructions to ensure product/material compatibility and
performance. This section has been modified to read: R703.91. Exterior
insulation and finish systems (EIFS). EIFS shall comply with the following:
(A) Item 1. ASTM E2568.
(B) Item 2. EIFS shall be limited to
applications over substrates of concrete or masonry wall assemblies.
(C) Item 3. Flashing of EIFS shall be
provided in accordance with the requirements of Section R703.4.
(D) Item 4. EIFS shall be installed in
accordance with same manufacturer's instruction as to ensure product/material
compatibility and performance.
(E)
Item 5. EIFS shall terminate not less than 6 inches (152 mm) above the finished
ground level.
(F) Item 6.
Decorative trim shall not be face-nailed through the EIFS.
(10) Section R703.9.2 Exterior insulation and
finish systems (EIFS) with drainage. This section has been modified to clarify
EFIS shall be installed in accordance with the same product manufacturer's
instructions to ensure product/material compatibility and performance. This
section has been modified to read: R703.9.2 Exterior insulation and finish
systems (EIFS) with drainage. EIFS with drainage shall comply with the
following:
(A) Item 1. ASTM E2568.
(B) Item 2. EIFS with drainage shall be
required over all wall assemblies with the exception of substrates of concrete
or masonry wall assemblies.
(C)
Item 3. EIFS with drainage shall have an average minimum drainage efficiency of
90 percent when tested in accordance with ASTM E2273.
(D) Item 4. The water-resistive barrier shall
comply with Section R703.2 or ASTM 2570.
(E) Item. 5. The water-resistive barrier
shall be applied between the EIFS and the wall sheathing.
(F) Item 6. Flashing of EIFS with drainage
shall be provided in accordance with the requirements of Section
R703.4.
(G) Item 7. EIFS with
drainage shall be installed in accordance with the same manufacturer's
instructions to ensure product/material compatibility and
performance.
(H) Item 8. EIFS with
drainage shall terminate not less than 6 inches (152 mm) above the finished
ground level.
(I) Item 9.
Decorative trim shall not be face-nailed through the EIFS.
