Current through Register Vol. 49, No. 39, March 24, 2025
Subpart
1. [Repealed, 32 SR 12 32 SR 12]
Subp. 2. [Repealed, 32 SR 12 32 SR
12]
Subp. 2a.
IRC section
R703.2 Water-resistive barrier.
Section R703.2 is amended to read as follows:
R703.2
Water-resistive barrier.
One layer of No. 15 asphalt felt, free from holes and breaks, complying with
ASTM D 226 for Type 1 felt or other approved water-resistive barrier shall be
applied over studs or sheathing of all exterior walls. Such felt or material
shall be applied horizontally, with the upper layer lapped over the lower layer
not less than 2 inches (51 mm). The water-resistive barrier shall overlap the
flashings required in section R703.8 not less than 2 inches (51 mm). Where
joints occur in the water-resistive barrier or flashing, the joints shall be
lapped not less than 6 inches (152 mm). The felt or other approved material
shall be continuous up to the underside of the rafter or truss top chord and
terminated at penetrations and building appendages in a manner to meet the
requirements of the exterior wall envelope as described in section R703.1.
Exception: Omission of the water-resistive barrier
is permitted in the following situations:
1. In detached accessory buildings.
2. Under exterior wall finish materials as
permitted in Table R703.4.
3. Under
paperbacked stucco lath when the paper backing is an approved water-resistive
barrier.
Subp.
3.
IRC section R703.
Section R703.6 is amended to read as follows:
R703.6
Exterior plaster.
Installation of these materials shall be in compliance with ASTM C 926
and ASTM C 1063 and provisions of this code.
R703.6.1
Lath. All lath and
lath attachments shall be of corrosion-resistant materials. Expanded metal or
woven wire lath shall be attached with 11 gage nails having a 7/16-inch (11.1
mm) head or 16 gage staples, spaced at no more than 6 inches (152 mm) or as
otherwise approved. Nails or staples shall penetrate wood framing support
members not less than 3/4-inch (19 mm).
R703.6.1.1 Control joints and expansion
joints. Provisions for the control of expansion shall be determined by the
exterior plaster application designer. ASTM C 1063 sections 7.11.4 - 7.11.4.4
do not apply.
R703.6.2
Plaster. Plastering with portland cement plaster shall be not
less than three coats when applied over metal lath or wire lath and shall be
not less than two coats when applied over masonry, concrete,
pressure-preservative treated wood, or decay-resistant wood as specified in
section R317.1 or gypsum backing. If the plaster surface is completely covered
by veneer or other facing material or is completely concealed, plaster
application need be only two coats, provided the total thickness is as set
forth in Table R702.1(1). On wood-frame construction with an on-grade floor
slab system, exterior plaster shall be applied to cover, but not extend below,
lath, paper, and screed.
R703.6.2.1
Weep screeds. A minimum 0.019-inch (0.5 mm) (No. 26 galvanized sheet
gage), corrosion-resistant weep screed or plastic weep screed, with a minimum
vertical attachment flange of 3-1/2 inches (89 mm) shall be provided at or
below the foundation plate line on exterior stud walls in accordance with ASTM
C 1063. The weep screed shall be placed a minimum of 4 inches (102 mm) above
the earth or 2 inches (51 mm) above paved areas and shall be of a type that
will allow trapped water to drain to the exterior of the building. The
weather-resistant barrier shall lap the attachment flange. The exterior lath
shall cover and terminate on the attachment flange of the weep
screed.
R703.6.3
Water-resistive barriers. Water-resistive barriers shall be installed as
required in section R703.2 and, where applied over wood-based sheathing, shall
include two layers of a water-resistive vapor-permeable barrier. Each layer
shall meet both of the following requirements:
1. A water resistance of not less than that
of 60-minute Grade D paper; or a minimum hydrostatic head of 23-31/32 inches
(60.9 cm) when tested in accordance with hydrostatic pressure test method AATCC
127-2008; or a minimum water transudation time of 60 minutes when tested in
accordance with ASTM D-779.
2. A
water vapor permeance of not less than that of No. 15 felt; or a minimum
permeance rating of 8.5 gr/h.ft.2 in Hg (US perm)
(4.9 x 1010kg/Pa.s.m2)
when tested in accordance with Procedure B of ASTM E96.
Exception: One layer of water-resistive barrier
complying with R703.2 is permitted when a drainage space that allows bulk water
to flow freely behind the cladding is provided.
R703.6.4
Application. Each coat
shall be kept in a moist condition for at least 48 hours prior to application
of the next coat.
Exception: Applications installed in accordance
with ASTM C 926. The second coat is permitted to be applied as soon as the
first coat has attained sufficient rigidity to receive the second coat.
R703.6.5
Curing. The
finish coat for two-coat cement plaster shall not be applied sooner than seven
days after application of the first coat. For three-coat cement plaster, the
second coat shall not be applied sooner than 48 hours after application of the
first coat, except as required in section R703.6.4. The finish coat for
three-coat cement plaster shall not be applied sooner than seven days after
application of the second coat.
Subp. 3a. [Repealed, 32 SR 12 32 SR
12]
Subp. 4. [Repealed, 32 SR 12 32
SR 12]
Subp. 5. [Repealed, 32 SR 12
32 SR 12]
Subp. 6. [Repealed, 32 SR
12 32 SR 12]
Subp. 7. [Repealed, 32
SR 12 32 SR 12]
Subp. 8. [Repealed,
32 SR 12 32 SR 12]
Subp. 8a.
Section R703.7.4.2.
IRC Section R703.7.4.2 is amended to read as follows:
R703.7.4.2
Air space. The veneer
shall be separated from the sheathing by an air space of a minimum of a nominal
1 inch (25 mm) but nor more than 4-1/2 inches (114 mm).
Exception: One layer of water-resistive barrier
complying with Section R703.2 is permitted when a drainage space that allows
bulk water to flow freely behind the cladding is provided.
Subp. 8b.
Section
R703.7.4.3.
IRC Section R703.7.4.3 is amended to read as follows:
R703.7.4.3
Mortar or grout fill.
As an alternate to the air space required by Section R703.7.4.2, mortar or
grout shall be permitted to fill the air space. When the 1-inch (25.4 mm) space
is filled with mortar, a weather-resistant membrane or building paper as
described in Section R703.2 or R703.6.3 is required over studs or sheathing.
When filling the air space, it is permitted to replace the sheathing and
weather-resistant membrane or asphalt-saturated felt paper with a wire mesh and
approved paper or an approved paper-backed reinforcement attached directly to
the studs.
R703.7.4.4
Masonry
veneer on sheathed substrates. On sheathed substrates, a
corrosion-resistant, self-furring expanded metal lath shall be installed over
the weather-resistant membrane or building paper with appropriate fasteners as
described in Section R703.6.1. Fasteners shall penetrate wood supports a
minimum of one inch.
Subp.
9.
IRC section R703.8.
Section R703.8 is amended to read as follows:
R703.8
Flashing. Approved
corrosion-resistant flashing shall be applied shingle-fashion in such a manner
as to prevent entry of water into the wall cavity or penetration of water to
the building structural framing components. Self-adhered membranes used as
flashing shall comply with AAMA 711. The flashing shall extend to the surface
of the exterior wall finish. Approved corrosion-resistant flashing shall be
installed at all of the following locations:
1. Exterior window and door openings.
Flashing shall be installed at the head and sides of exterior window and door
openings and shall extend to the surface of the exterior wall finish or to the
water-resistive barrier for subsequent drainage. Flashing at exterior window
and door openings shall be installed in accordance with at least one of the
following:
(a) the fenestration manufacturers
installation and flashing instructions. When flashing is not addressed in the
fenestration manufacturers instructions, it shall be installed in accordance
with the flashing manufacturers instructions;
(b) in accordance with the flashing design or
method of a registered design professional; and
(c) in accordance with other approved
methods.
2. At the
intersection of chimneys or other masonry construction with frame or stucco
walls, with projecting lips on both sides under stucco copings.
3. Under and at the ends of masonry, wood, or
metal copings and sills.
4.
Continuously above all projecting wood trim.
5. Where exterior porches, decks, or stairs
attach to a wall or floor assembly of wood-frame construction.
6. At wall and roof intersections.
8. Where exterior material meets in other
than a vertical line.
9. Where the
lower portion of a sloped roof stops within the plane of an intersecting wall
cladding in such a manner as to divert water away from the assembly in
compliance with section R903.2.1.
10. At the intersection of the foundation and
rim joist framing when the exterior wall covering does not lap the foundation
insulation.
R703.8.1
Pan
flashing of windows and doors.
Pan flashing shall be installed in accordance with the
fenestration manufacturers installation and flashing instructions. Where
flashing instructions or details are not provided, pan flashing shall be
installed at the sill of exterior window and door openings. Pan flashing shall
be sealed or sloped in such a manner as to direct water to the surface of the
exterior wall finish or to the water-resistive barrier for subsequent
drainage.
Exceptions:
1. Windows or doors installed in accordance
with the manufacturers installation instructions which include an alternate
flashing method.
2. Windows or
doors in detached accessory structures.
3. Skylights, bow or bay windows.
4. Doors required to meet accessibility
requirements that would prevent the installation of pan flashing.
5. Repairs or replacement of existing windows
and doors.
6. When a method is
provided by a registered design professional.
Statutory Authority: MS s
16B.59;
16B.61;
16B.64;
326B.02;
326B.101;
326B.106;
326B.13
