Metal Lath, Beads and Trims
Stucco and Plaster Accessory
Products and Applications
Course Number: DIE05L
An AIA Continuing Education Program
Credit for this course is 1.5 AIA HSW CE Hours
ClarkDietrich Building Systems
Janine Dallies, CSI, CDT
1985 N. River Road
Warren, Ohio 44483
330-372-5564 ext. 64235
janine.dallies@clarkdietrich.com
www.clarkdietrich.com
© Ron Blank & Associates, Inc. 2009
An American Institute of Architects (AIA)
Continuing Education Program
Approved Promotional Statement:
Ron Blank & Associates, Inc. is a registered provider with The American Institute of
Architects Continuing Education System. Credit earned upon completion of this program will
be reported to CES Records for AIA members. Certificates of Completion are available for
all course participants upon completion of the course conclusion quiz with +80%.
Please view the following slide for more information on Certificates of Completion through RBA
This program is registered with the AIA/CES for continuing professional
education. As such, it does not include content that may be deemed or
construed to be an approval or endorsement by the AIA or Ron Blank &
Associates, Inc. of any material of construction or any method or manner
of handling, using, distributing, or dealing in any material or product.
An American Institute of Architects (AIA)
Continuing Education Program
Course Format: This is a structured, web-based, self study course with a final exam.
Course Credit: 1.5 AIA Health Safety & Welfare (HSW) CE Hour
Completion Certificate: A confirmation is sent to you by email and you can print one
upon successful completion of a course or from your RonBlank.com transcript. If you
have any difficulties printing or receiving your Certificate please send requests to
certificate@ronblank.com
Design professionals, please remember to print or save your certificate
of completion after successfully completing a course conclusion quiz.
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Course Description
Become familiar with metal lath products and stucco and plaster
accessories that are available in galvanized steel, zinc alloy and
vinyl. Examine trim and bead products used for veneer, stucco and
plaster applications, and identify the benefits of using vinyl
accessory products.
Course Introduction
This course is divided into 4 Sections:
1.
Sheet Metal Lath
2.
Rolled Metal Lath Alternatives
3.
Stucco Accessories
4.
Veneer Plaster Accessories
Learning Objectives
Upon completion of this course, the design professional will be able to:
• Discuss differences in metal lath products and understand materials
and procedures for safe and proper installation
• Describe stucco and plaster accessories that are available in
galvanized steel, zinc alloy and vinyl and which accessory to use
depending on the application to ensure optimum performance
• Describe trim and bead products used for veneer, stucco and
plaster applications and which accessory to use depending on the
application to ensure optimum performance
• Discuss the types of vinyl accessory products and how they
compare and contrast to their metal counterparts
Section #1
Sheet Metal Lath
Sheet Metal Lath Product Overview
• Manufactured from steel sheets that are slit and expanded to form
small diamond openings (approximately 11,000 per square yard).
• Metal lath’s main function is to aid in the application of Portland
cement stucco to a structure.
• Openings provide for plaster keying. This allows for better stucco
bonding in either pumped or troweled applications. The stucco
must be properly keyed or forced through the diamond mesh, to
ensure proper embedment.
• Can be used for wall, ceiling, floor construction as well as for
ornamental designs.
• Standard nominal size of 27” x 96”
Commonly Used Industry Terms
• Stucco: A cementitious mixture used for exterior plaster. It
consists of a Portland based cementitious mix combined with water
and with or without aggregate. This material provides the plasticity
and the cohesive and adhesive properties necessary for placement
and formation of a rigid mass.
• One Coat System: Utilizes metal lath with an acrylic modified
stucco. This is applied in one application and the finished surface
has an EIFS (Exterior Insulation and Finish Systems) appearance.
• Two Coat System: Utilizes the application of plaster in two
successive coats.
Commonly Used Industry Terms
Three Coat System: Utilizes the application of plaster in three
successive coats, leaving time between coats for setting, drying or
partial drying.
•
•
•
Scratch Coat: Refers to the first coat of plaster in a three coat system.
Brown Coat: Refers to the coat of plaster directly beneath the finish coat.
In a two coat system, it is the base coat.
Finish Coat: Refers to the final coat of plaster (applied to the top of the
brown coat. )
Metal Lath Industry Standards
The American Society for Testing and Materials (ASTM) is the governing
body that prescribes standard specifications for products used in construction.
ASTM C- 847 is the applicable specification providing guidelines for the
manufacture of metal lath.
ASTM C-847
Abstract
This specification covers sheet lath, expanded metal lath, diamond mesh, flat and selffurring, and rib metal lath, all with or without backing and designed to be used as a
base for gypsum or Portland cement plaster. Metal lath shall be fabricated from coldrolled carbon steel sheet of commercial quality as specified and galvanized metal lath
shall have a G60 coating. Physical properties such as thickness, width, length, and
weight shall be specified. Metal lath shall be fabricated from hot-dipped galvanized
steel.
1. Scope
1.1 This specification covers sheet lath, expanded metal lath, diamond mesh, flat and
self-furring, and rib metal lath, 1/8 and 3/8 in. (3.2 and 9.6 mm), all with or without
backing and designed to be used as a base for gypsum or Portland cement plaster.
1.2 The values stated in inch-pound units are to be regarded as standard. The values
given in parentheses are mathematical conversions to SI units that are provided for
information only and are not considered standard.
Metal Lath Industry Standards
•
The ICC-ES (International Code Council Evaluation Service) references
ASTM C-847 in product evaluation reports as the standard that must be
met.
•
The following slides represent a sample report.
Metal Lath
Industry Standards
Metal Lath Industry Standards
Expanded Metal Mesh
• Metal lath is sold based
upon weight per square
yard of material.
• It is available in three
different weights:
•
1.75 lbs./sq. yd.
•
2.5 lbs./sq. yd.
•
3.4 lbs./sq. yd.
• What do these weights
mean?
Buyer Beware!
• The specified weight of product means one square yard
of product (9 square feet) should weigh that stated
weight.
– Example: 3.4 lbs./sq. yd. means that one square yard of this
lath should weigh 3.4 pounds
– The typical sheet of metal lath is manufactured in 27” x 96”
sheets which contains 2 square yards of product
• One sheet of 3.4 lath should weigh 6.8 pounds +/allowable tolerances (see ASTM C847).
• Beware - some manufacturers are selling product that
weighs less than it should!!!!
Expanded Metal Mesh Installation
• This variety of lath is generally
applied to studs (wood or metal)
in open frame construction. Flat
mesh should not be used over a
solid surface (gypsum, concrete,
wood sheathing) as the absence
of a “furring mechanism” will
cause the stucco to bond only to
the sheathing and not complete
the embedding process.
• Note: 1.75 lath is not
recommended for open frame
use other than in tested
proprietary one coat systems.
Expanded Metal Mesh Installation
Wafer head screws are power driven
to allow quick and easy attachment to
the framing member (wood or steel).
Expanded metal mesh lath can
be cut to size with hand tools.
Self-Furred Metal Lath
There are two types of self-furred metal lath – dimpled (photo on left)
and v-grooved (photo on right). This lath is very similar to regular
expanded metal mesh lath but it has dimples or embossed v-grooves
measuring approximately 1/4” deep manufactured into the surface of
the lath.
Self-Furred Lath Application
•
This variety of lath is generally used in applications over solid surfaces
such as block, concrete or sheathing products.
•
Available in three different weights:
– 1.75 lbs./sq. yd.
–
2.5 lbs./sq. yd.
–
3.4 lbs./sq. yd.
Self-Furred Lath Application
• The “self-furring” lath allows the
stucco to key or lock into the metal
lath ensuring that it becomes fully
embedded. The lath also acts as
an “attachment mechanism” for
the lath and stucco to the structure
or structural framing.
• Note: Individual market
preference dictates use of VGrooved or Dimpled.
Self-Furred Lath Installation
*Ex. - Three coat system utilizing LAD
Self-furred lath is secured to masonry
surfaces with hardened nails or powder
driven fasteners at the furring dimples.
Paper backed lath is often used in this
type of application as a bond breaker.
The scratch coat is applied with
complete embedment of the plaster into
the self-furred lath.
Self-Furred Installation
“Scratching” the scratch coat for maximum
bonding of brown coat to the scratch coat.
This is done to increase adhesion of the
second coat.
“Darbying” the brown coat to render a plumb
and even surface. A “Darby” is a flat wooden
tool designed to smooth out or “float” the
brown coat.
*The last coat of stucco would simply be the “Finish Coat.”
Rib Lath
• Rib lath is the most rigid of all sheet laths and is
commonly used for soffits and ceilings.
• It is available in 3/8” High Rib and 3.4 lbs./sq. yd.
• Rib lath is not considered a self-furred product.
Rib Lath Application
•
•
•
The main difference between rib lath and flat mesh or self-furring is that it
contains solid ribs running the length of the piece.
The solid ribs provide additional rigidity to the lath product.
High Rib is used primarily in horizontal applications and is also an
excellent product for framing spaced no more than 24” on center.
Asphalt Paper-Backed Metal Lath
•
•
Type: 2” double offset paper
Available in three different weights:
– 1.75 lbs./sq. yd.
– 2.5 lbs./sq. yd.
– 3.4 lbs./sq. yd.
Asphalt paper-backed metal lath is expanded metal mesh lath, regular or selffurred to which asphalt saturated Kraft building paper is applied. The paper
sheet acts as a water barrier, care must be taken not to rip or puncture the
paper
Asphalt Paper-Backed Application
•
•
•
•
Asphalt papered lath is designed to reduce moisture penetration while allowing for
the dissipation of moisture vapor from within the structure. The paper is designed to
aid in the funneling or “wicking” of moisture to the bottom of the stucco membrane
where it can escape from the wall cavity.
The paper backing also aids in plaster “keying” and stucco curing. It provides for
protection of the sheathing during the curing process. Deterioration of the sheathing
may occur without this protection.
Industry standard paper provides a 10 minute water resistance rating. This is
referred to as Grade D paper. Some metal lath manufacturers offer increased water
resistant paper.
The paper can also be applied directly to the solid structure and non-paper lath
products can then be used. In most areas of the country, two layers of Grade D
paper are required, the paper would be applied to the structure followed by the
application of a paper-backed lath product. A house wrap (moisture barrier) may be
used in lieu of one layer of Grade D paper but must be applied directly to the
structure and topped by the second layer of the paper backed lath product.
Asphalt Paper-Backed
“Over Lap” Installation
•
•
ASTM C-1063 requires that the paper
backing must overlap a minimum of 2” and
the lath-to-lath must overlap 1”.
Fasteners must penetrate both sheets of
metal lath.
Paper backing
overlap
Lath overlap
Asphalt Paper-Backed Installation
Scratch coat is fully embedded in the
lath and is isolated from supporting
structure. Water resistant backing paper
allows for controlled and uniform
curing of this plaster foundation.
Notice in this picture the extra
fasteners at the “overlap” of the lath.
Where side laps occur, wire ties are
required between the fasteners.
Kraft Paper-Backed Lath
•
•
•
Kraft paper-backed lath products are very similar to the asphalt
impregnated Kraft paper-backed products. However the paper used is not
asphalt saturated thus it does not provide a water resistant barrier. The
paper is simply used to act as a “backer” to conserve machine applied
stucco. Another benefit is during attachment of the lath to the structure
the framing members are visible behind the paper.
Kraft paper-backed lath is available in rib lath as well as diamond mesh
Traditionally Kraft paper-backed lath has been used exclusively on the
west coast.
3/8” rib lath with Kraft paper-backing ribs
Fastening to Wood Framing
•
•
When fastening metal lath to wood framing use 1-1/2” roofing nails or 6d
common nails driven into the framing member 3/4”. Then bend nail over to
engage not less than (3) “diamonds”. Large head nails (7/16”) can be
driven in flush. Also one-inch staples may be used. It is recommended that
mechanical fasteners be attached at 7” intervals. However, check local
requirements as they may be more restrictive.
When fastening Rib Lath to any framing
member the fastening mechanism must be
attached through or over the rib.
Fastening to Metal Framing
When attaching metal lath to steel framing use
screws that have a minimum number “8” shank
with a wafer head not less than 7/16” wide. The
screw must penetrate the framing member by
3/8”. Mechanical fastening is recommended at 7”
intervals but again, local requirements will prevail.
Fastening to Concrete or Block
When attaching metal lath directly to
concrete or block use powder
activated fasteners in unison with
washers 3/4” in diameter. These
fasteners must be located at each
corner and mid-span on the sheet.
The interior portion may be fastened
with concrete “stub nails.”
Fastening to Cold Rolled Channel in a
Suspended Ceiling Application
When fastening metal lath to cold rolled channel in a suspended ceiling
application, wire tying with 18 gauge hanger wire is required . Wire ties must
be no more than 7” on center. (Refer to IBC and ASTM C-1063 for furring and
main support spacing.)
Ceramic Tile Application
•
•
Paper-backed metal lath is often used as a backer for ceramic tile in
unison with Portland cement as a tile base. Lath types and installation are
similar to that of exterior framing. If you are constructing an “open frame”
use a paper-backed flat mesh and if it is used over a solid surface use
paper-backed self-furring.
Note: This application is considered for “high humidity” areas. Zinc or vinyl
trims are recommended over galvanized trims.
“Floor Leveling” Application
Metal lath may also be used to aid in the leveling of uneven floors. Self-furred
1.75 or 2.5 is attached to the floor with powder actuated fasteners or stub
nails. Portland cement stucco is then used to level the floor. This method is
especially popular when a concrete pour will be done over an existing
concrete base. The lath ties both layers together.
Ornamental Application
Expanded metal mesh lath can be formed into “trees and rocks”, then coated
with stucco. Painting it gives a realistic appearance.
Section #2
Rolled Metal Lath Alternatives
Alternative Stucco Reinforcing Products
ICC Approved alternatives for 2.5, 3.4 and 3/8” rib sheet lath products
• Welded wire in rolls
• Comply with IBC, IRC, & UBC
• Tested and evaluated
• Performance in transverse load tests show products are equal to or better
than traditional metal lath sheets
Alternative Stucco Reinforcing Products
Alternative products incorporate new benefits for plaster walls:
• Engineered to improve embedment
• Reduce cracking in stucco
• Promotes uniform plaster thickness
• Easy to install – less cuts – less overlaps
• Easy attachment for steel and wood stud construction
• Engineered to provide a strong, durable stucco wall assembly
Improved Corrosion Resistance
Additional coating enhancements are available that
can provide upwards of 20% more corrosion
resistance than regular zinc coated metal products.
Ideal for use on coastal and higher humidity area
projects.
Welded Wire Stucco Reinforcing
Various Types: Regular
• 1-1/2" x 1-1/2" welded
wire (17 ga) – self
furred
Welded Wire Stucco Reinforcing
• 1-1/2" x 1-1/2" welded wire (17 ga) with the addition of eight
secondary cold-rolled longitudinal wires that add strength to form a
'track' for convenient attachment.
• Potential alternative wherever 2.5 metal lath has been specified.
Welded Wire Stucco Reinforcing
Various Types: Heavy Duty
•
•
•
Dense product made from 17 ga galvanized steel wire welded to form 0.7
inch x 1.5 inch openings
Reinforcing for both stucco and stone installation
Potential alternative wherever 3.4 metal lath has been specified
Heavy Duty Welded Wire
Stucco Reinforcing
Veneer Stone Reinforcing
•
•
•
Problems with simulated stone installations have also grown dramatically.
These problems are associated with moisture ingress and subsequent
deterioration of the structure and elements in behind the stone.
Dense Heavy-Duty welded wire lath provide full ¼” furrs (minimum 28 per
sq/ft) that ensure a minimum 3/8” to ½” scratch coat. This thick plaster
coat is critical to effective water barrier
When welded wire is installed with approved fasteners & spacing, the lath
can safely support over 100psf dead load. Maximum stone weight is 15psf
and plaster weight is 10psf. Therefore there is a 4:1 safety factor.
Welded Wire Stucco Reinforcing
Various Types: Truss Sheet Product
• Series of 3/8 - inch ' V ' shaped trusses, and heavy perforated draft paper
that is sandwiched between the primary sheet and a back layer of
stiffening wires.
• The sheets are light weight yet strong and easy to cut.
• Potential alternative wherever 3.4 Rib Lath has been specified
• Improved performance on soffits.
Welded Wire Stucco Reinforcing
Truss Sheet Product
Truss Sheet Product Features
•
•
•
•
•
•
•
Made from 17 ga galvanized steel wire weld wire
Rectangular openings
Self furred to ensure a full 3/8" scratch coat
Flat bottomed furr will not puncture vapor barrier
Cold rolled - flat longitudinal wires reduce curvature memory for an easy to
handle roll – while increasing tensile strength
Cold rolled longitudinal wires form a twin track that simplifies attachment
Rolls are more manageable than sheet products and make for easy
installation
Section #3
Stucco Accessories
Terminology
•
•
•
Stucco: Term used within the industry to refer to a Portland cement-based
cementitious mixture. Many industry experts use the term plaster to
denote interior work and stucco to denote exterior work.
Veneer Plaster: Often referred to as gypsum plaster. It refers to a plaster
that is applied over a gypsum product to create a “finished” stucco
appearance on interior walls.
Ground: This is a term that is used to identify the “depth” of the plaster
base and thus the size of the accessory. The thickness of the plaster is
determined by the height of the ground on those accessories with
grounds.
Industry Standards
• ASTM C-1063 is the applicable specification which covers the
minimum requirements for lathing and furring for the application of
exterior and interior Portland cement-based plaster. In simpler
terms it covers attachment and the associated accessory products
that are used with metal lath and stucco.
• One key piece of information to remember from ASTM C-1063 is
the following: “All materials shall be kept dry. Materials shall be
stacked off the ground, supported on a level platform, and
protected from the weather and surface contamination.”
• Vinyl products must meet or exceed ASTM D-1784 and D-4216
cell class 13244C.
Corrosion Resistance
• Zinc alloy and vinyl plaster trims should be used for installations
where abnormal corrosion is possible due to high humidity and
continual moisture exposure.
• Examples include: bath and shower rooms, green-houses,
swimming pool areas, etc.
• They are also prescribed where adverse atmospheric conditions
may exist (high saline content or acid rain) such as in coastal
regions or heavy industrial areas.
1-A Expanded Corner Bead
•
•
•
•
•
1-A Expanded Corner Bead is the standard accessory for providing
exterior corner protection and providing a reliably straight ground.
Easily flexed for irregular corners.
Reinforced close to the nose of the bead.
Made with 2-7/8” or 3” wide expanded flanges in
galvanized steel and zinc alloy.
Available in:
– Galvanized: 8’ and 10’
– Zinc: 10’
1-A Vinyl Corner Bead
Dimensions
2–1/2” x 2–1/2”
• provides rust-proof corner reinforcement
2–1/2” x 2–1/2”
• corner reinforcement for narrow returns
1–1/2” x 1–1/2”
• corner reinforcement for narrow bands and reveals
2–3/4” x 2–3/4”
• heavier version and increased flange width, used in
high traffic areas
2–3/4” x 1–1/2”
• for applications requiring increased damage
resistance
Double-X Corner Bead
Ideal for structural tile and rough masonry. Adjusts easily for varying plaster
depth on columns. The added stiffener strip affords additional rigidity to the
flange.
# 66 Expanded Flange Casing Beads
The expanded flange casing bead is
used as a plaster stop or exposed
trim around doors and windows.
May also be used as an expansion
joint when installed “back to back.”
Available in galvanized and zinc.
# 66 Expanded Flange Information
•
•
•
Galvanized: Available in grounds ranging from
3/8” - 1 1/4” (additional sizes available on special
order). This part is also available with weep
holes. Weep holes are designed to allow
moisture trapped behind the stucco to escape.
Zinc: Available in grounds ranging from 1/2” - 1”
(additional sizes available on special order). This
part is also available with weep holes.
Caution: Punched holes in the ground
of casing beads should not be construed
as a replacement for foundation weep
screeds for traditional three-coat stucco
applications. This should be used only
were required by certain one-coat systems.
# 66 Short Flange Casing Bead
This product is very similar to the #66
expanded flange product except that it does
not have the expanded flange. Both nail and
key holes are provided in the flange. The
product is available in both galvanized and
zinc and with or without weep holes.
Both products are available in
grounds ranging from
3/8” through 1”
Vinyl Casing Bead - Short
and Long Flange
Short Flange - 1 3/4”
Long Flange - 2 1/2”
Used to terminate stucco and plaster against doors, windows and
dissimilar materials. Available in ground heights:
• 1/4” (short
• 3/8”
• 5/8”
• 7/8”
flange only)
• 1/2”
• 3/4”
• 1”
Control/Expansion Joints
•
Stucco, under various types of stress and deflection, will develop cracks.
Control/expansion joints are used to minimize this problem. It has been
determined that if stucco is divided into smaller areas (144 square feet for
walls/100 square feet for ceilings), the stress on the stucco membrane is
reduced enough to significantly reduce most cracking. Control joints are
used to make divisions and to allow movement/stress to occur in order to
minimize the effect of such stress on the stucco membrane.
•
Market preference will often dictate use of a particular control joint.
Zinc Control Joints
•
Common ground heights:
•
3/8”, 1/2”, 3/4” and 1”
This product is designed to
relieve stresses of expansion
and contraction in large
plastered (stucco) areas. This
product offers a 1/4” slot which
is protected with a plastic tape.
The tape should not be
removed until both plastering
and finishing are completed,
leaving a clean, finished
appearance.
Vinyl Control Joint with Removable Tape
Recommended for smooth finishes. Positive attachment of each flange of
control joint to separate framing is required
Ground heights:
• 1/4”
• 3/8”
• 5/8”
• 7/8”
• 1/2”
• 3/4”
•
1”
#15 Double - V Control Joint
This product provides stress relief to control cracking in large plastered
(stucco) areas. The flanges are expanded metal.
Available in both
galvanized and zinc and
in grounds ranging from
3/8” to 1-1/4”.
This product is not
protected with a plastic
tape.
#15 Double-V Vinyl Control Joint
Vinyl beads and trims are used to provide
durable, corrosion and impact-resistant
edges, corners, arches, curvatures and
numerous other finishing applications.
Ground heights:
• 3/8”
• 5/8”
• 7/8”
• 1/2”
• 3/4”
•
1”
Double - J Control Joint
Double-J is available in both
galvanized as well as zinc and in
grounds ranging from 1/2”, 3/4” and
7/8”. Removable tape provides for
easy joint cleaning.
This product provides
excellent expansion control
for both walls and ceilings
while offering positive
locking of the stucco to the
edge of the joint. This is
accomplished by “forcing”
the stucco up under the “J”
during application. With this
product, the shrinking that
often occurs as freshly
applied stucco dries is
hidden under the “J”.
#40 Two Piece Expansion Joint
Many people consider this product to be the only true expansion joint in the
industry, due to the fact that each piece can move independently of the other.
This product should be used where excessive horizontal and vertical
movement occur. Atriums and other wide walls are areas where this product
is recommended. The prescribed expansion opening/reveal is 1/4” to 5/8”. It
is available in both galvanized and zinc and in 1/2”, 3/4” and 7/8” grounds.
Vinyl Two Piece Expansion Joint
Designed to relieve stress in wall
and ceiling areas where excess
horizontal and vertical
movements might occur.
Ground heights: • 3/8”
• 3/4”
• 1/2”
• 7/8”
• 5/8”
• 1”
Corner Control Joint
An “inside corner” expansion joint, it is designed
to reduce cracking and allow movement at inside
corners of wall to wall junctures resulting from
expansion and contraction.
Ground Depth
Available in both galvanized and
zinc and in 1/2”, 3/4” and 7/8”
grounds.
Vinyl Corner Control Joint
Relieves stress caused by expansion and
contraction in wall and ceiling inside angles.
Removable tape protects deep “V”
expansion slot during construction.
Ground heights:
• 1/2”
• 3/4”
• 5/8”
• 7/8”
• 1”
Channel Reveals
Reveal
Channel reveals are used to
create 1/2” to 4” reveals in stucco
and plaster surfaces. They allow
for precision field assembly and
clean appearance when
decorative applications are
designed.
Channel Reveals
•
Factory fabricated intersections are used to form clear channels in vertical
and horizontal intersections of Crosses, T’s, L’s, Inside and Outside
Corners and End Closures of channel reveals.
•
The following two slides are examples of some of the factory fabricated
channel reveal intersections that are available.
Channel Reveal Intersections
Channel Reveal Intersections
One-Piece Soffit Vent
One-piece soffit vent designed for
plywood, soffit board and three-piece
stucco and plaster vents. Use vent clips
to connect soffit vent and assist in
alignment.
Continuous One-Piece Soffit Vent
Continuous one-piece soffit vent with reinforcing
rib to key into stucco and plaster. Again, use
clips to connect and assist in alignment.
Vent area is 15 square inches per lineal foot.
J-Style Soffit Vent
Another example of a continuous onepiece soffit vent. “J” bead flanges cover
raw edges of soffit board.
Strip Lath
Strip lath is essentially diamond mesh lath formed into strips. This
product is used at the corners of all openings such as doors and
windows for reinforcement. Openings often cause weakened areas
that are prone to cracks. Strip lath can be used to reinforce any
weakened area in the lath assembly.
Available in:
4” x 8’ and 6” x 8’
Corner Lath
Corner lath is strip lath bent to an obtuse angle with smooth edges
also formed like diamond mesh. It is used in corners (intersections)
where walls meet walls or ceilings. This reinforcing of interior corners
helps prevent cracks.
Available in:
2” x 2” x 4’
2” x 2” x 8’
3” x 3” x 8’
#7 Foundation Screed
This part is often referred to as F.H.A. Screed because it meets all pertinent
requirements. The screed provides an angular, straight-edge stop at the sill
plate line and can be attached by nail or staple. The product is manufactured
from 26 gauge material and is available in ground heights of 7/8” and 1-3/8”.
It has a 3-1/2” nailing flange and weep holes are provided to eliminate
condensation problems.
Vinyl Foundation Weep Screeds
Designed to relieve moisture from stucco and act as a stop. Installed on
frame construction where stucco and foundation walls meet. Ground heights:
• 3/8”
• 1/2”
• 5/8”
• 3/4”
• 7/8”
4” overall width, with unperforated flange
J Weep High Back Plaster Stop
This part is manufactured from 26 gauge galvanized steel. It is available in
both a 7/8” and 1-3/8” grounds with a 3-1/2” nailing flange. It is designed to
be used as a plaster stop at the sill plate or door and window openings. It is
designed with weep holes to allow for drainage of moisture from the stucco
membrane.
J Weep Low Back Plaster Stop
This part is similar in application to the high back plaster stop. The only
difference is it has a 2” nailing flange versus the 3-1/2”. Without weep holes it
is available in 1-3/8” grounds. If weep holes are required the part is available
in both 7/8” and 1-3/8” grounds.
Caution: Punched holes in the ground of casing beads should not be
construed as a replacement for the foundation weep screeds for traditional
three-coat stucco applications. This should be used only were required by
certain one-coat systems.
Vinyl J-Weep Screed
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High back plaster stop
3-1/2” overall width
Ground heights:
– 7/8”
– 1-3/8”
Acts as a stop, and designed
with an unperforated flange to
allow moisture removal from
stucco installations at stucco
termination points. Not to be
used in place of a foundation
weep screed.
•
Section #4
Veneer Plaster Accessories
ASTM C-1047
Abstract
This specification covers accessories used in conjunction with assemblies of
gypsum wallboard and gypsum veneer base to protect edges and corners and
to provide architectural features. Steel accessories and steel components of
accessories manufactured from steel and paper in combination shall be
manufactured from zinc-coated cold-roll sheet steel before application of
coating. Phosphatizing or other surface treatments may be used to ensure
compatibility and bond. Paper components of accessories manufactured from
steel and paper in combination shall comply with requirements for thickness,
tensile strength, dimensional stability, and bond of joint tape to joint
compound. Accessories shall be free of twist or camber of a degree that will
prevent their use in the assembly for which they are intended. Edges of
accessories shall be free of burrs and sharp edges.
ASTM C-1047
1. Scope
1.1 This specification covers accessories used in conjunction with assemblies
of gypsum wallboard and gypsum veneer base to protect edges and corners
and to provide architectural features (see Fig. 1).
1.2 The values stated in inch-pound units are to be regarded as standard. The
values given in parentheses are mathematical conversions to SI units that are
provided for information only and are not considered standard.
Mini-Beads
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Mini-mesh corner beads are manufactured with a 1-1/4” expanded flange.
The flange may be either nailed or stapled to the gypsum substrate.
They can be used with veneer plaster or even drywall compound over a
gypsum base.
Mini-beads are available in two
ground heights:
– 1/16” for one-coat veneer
plaster systems
– 3/32” for two-coat veneer
plaster systems
Mini-beads are manufactured in both
galvanized and zinc.
701A & 801A Veneer Trims
•
This “J” shaped trim is manufactured in different depths and grounds to
accommodate veneer finishes. The product is available in galvanized or
zinc for cement board applications. Both 701A & 801A are available in
either 1/2” or 5/8” depths to match up to the different substrate thickness.
•
The “J-trim” provides for neat edge protection at cased openings and
ceiling/wall intersections. The fine mesh expanded flanges strengthen
veneer plaster bond and eliminate shadowing.
701B & 801B Veneer Trims
This is an “L” shaped trim designed for use at the junction of the gypsum base
with rough concrete or a masonry ceiling. This product is manufactured in
various grounds and depths of 1/2” and 5/8” to accommodate the different
substrate thicknesses. It is available in galvanized as well as zinc.
093 Control Joints
The 093 Control Joint is used to relieve the stresses of expansion and
contraction across the joint in large ceiling and wall areas in veneer finish
systems. The product is made from zinc or vinyl to resist corrosion and has
3/32” grounds. “Plastic Tape” protects the opening and it is to be removed
only after finishing is complete.
093 Control Joint Application
According to the Association of the Wall and Ceiling Industries, control joints
should be installed in ceilings exceeding 2500 square feet. The distance
between control joints shall not exceed 50’. Control joints should also be
installed where ceiling framing or furring changes direction. In partitions,
walls or wall furring, the distance between control joints shall not exceed 30’.
Course Summary
The design professional will now be able to:
• Discuss differences in metal lath products and understand
materials and procedures for safe and proper installation
• Describe stucco and plaster accessories that are available in
galvanized steel, zinc alloy and vinyl and which accessory to use
depending on the application to ensure optimum performance
• Describe trim and bead products used for veneer, stucco and
plaster applications and which accessory to use depending on the
application to ensure optimum performance
• Discuss the types of vinyl accessory products and how they
compare and contrast to their metal counterparts
Metal Lath, Beads and Trims
Stucco and Plaster Accessory
Products and Applications
Course Number: DIE05L
An AIA Continuing Education Program
Credit for this course is 1.5 AIA HSW CE Hours
ClarkDietrich Building Systems
Janine Dallies, CSI, CDT
1985 N. River Road
Warren, Ohio 44483
330-372-5564 ext. 64235
janine.dallies@clarkdietrich.com
www.clarkdietrich.com
© Ron Blank & Associates, Inc. 2009