USACE / NAVFAC / AFCESA / NASA UFGS-09 22 36 (January 2008)
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Preparing Activity: NAVFAC Superseding
UFGS-09 22 36.00 20 (April 2006)
UFGS-09 22 37.00 10 (April 2006)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 09 22 36
LATH
01/08
NOTE: This guide specification covers the requirements for lathing for gypsum
and portland cement-based plaster work.
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
NOTE: Metal framing, furring and ceiling suspension systems for lathing are
specified in Section 05 40 00 COLD-FORMED METAL FRAMING and Section 09 22 00
SUPPORTS FOR PLASTER AND GYPSUM BOARD.
NOTE: If discoloration of exterior plaster work along the lines of the framing
system used to support the lath (metal framing in particular and wood framing
to a lesser extent) occurs or is anticipated, design the exterior wall with
a thermal break between the metal lath and the framing members. One suggested
solution is to install 12.7 mm 1/2 inch thick gypsum sheathing board, conforming
to ASTM C 79, "Gypsum Sheathing Board," on the framing members before attaching
the metal lath.
NOTE: On the drawings, show:
1. Location and extent of plastering
2. Type(s) and spacing of supports
3. Type(s) of plaster and location
4. Control joint locations
5. Fire resistance rating(s), where applicable
6. Sound transmission class (STC) rating(s), where applicable
7. Location and size of access panels and fabrication details for access panels
larger than 600 by 900 mm 24 by 36 inches.
PART 1 GENERAL
1.1 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to within the text by the basic designation only.
[ASTM INTERNATIONAL (ASTM)ASTM C 1063(2008) Standard Practice for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based PlasterASTM C 841(2003e1; R 2008) Installation of Interior Lathing and Furring][GYPSUM ASSOCIATION (GA)GA 600(2003) Fire Resistance Design Manual][UNDERWRITERS LABORATORIES (UL)UL Fire Resistance(2008) Fire Resistance Directory]1.2 SUBMITTALS
NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are [for Contractor Quality Control approval.][for information only. When used, a designation following the
"G" designation identifies the office that will review the submittal for the Government.] Submit the following
in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-03 Product Data
Lath
Accessories
Access panels
1.3 DELIVERY AND STORAGE
Deliver materials in the manufacturer's original unbroken packages or containers that are labeled plainly with
the manufacturer's names and brands. Store materials in dry locations with adequate ventilation, free from water,
and in such a manner to permit easy access for inspection and handling. [Stack gypsum lath flat to avoid sagging
or damage to edges, ends, or surfaces, and protect from exposure to direct sunlight.]
PART 2 PRODUCTS
NOTE: This guide specification presents nonproprietary materials. When the
guide specification is edited or supplemented to suit project requirements,
care shall be exercised to present a project specification section which contains
no proprietary materials.
2.1 LATH
2.1.1 Metal Plastering Base (Lath)
Provide the type(s) and weight(s) required for the type and spacing of supports shown for the kind of plaster
indicated and specified. Do not use rib lath for ceramic tile scratch coat.
2.1.1.1 For Portland Cement-Based Plaster (Stucco)
ASTM C 1063,[ diamond mesh][ self-furring diamond mesh][ flat rib][ 10 mm3/8 inch rib][ 20 mm3/4 inch rib][ sheet][
welded wire][ woven wire] metal lath weighing not less than [_____] kilograms per square meter pounds per square
yard.
2.1.1.2 For Gypsum Plaster
NOTE: Consult Table 2 in ASTM C 1063 and Table 1 in ASTM C 841 to determine
the type and weight of the metal lath based on the type and spacing of the support
system shown on the project drawings.
ASTM C 841,[ diamond mesh][ self-furring diamond mesh][ flat rib][ 10 mm3/8 inch rib][ 20 mm3/4 inch rib][ sheet][
welded wire][ woven wire] metal lath weighing not less than [_____] kilograms per square meter pounds per square
yard.
2.1.1.3 Paper Backing (Waterproofed Kraft Building Paper)
NOTE: Specify "Moderate water-vapor Resistant" where moisture protection or
use of vapor barrier is required. Specify "Water-vapor permeable" to maintain
hollow partitions plaster free, to prevent plaster from bonding to substrate,
to prevent over spray where plaster is sprayed on, to provide uniform plaster
thickness and to improve bonding (keying). Edit paragraph as required.
Provide metal plastering base with paper backing,[ "Moderate water-vapor Resistant" for room(s) [_____]][ "Water-vapor
permeable" for room(s) [_____]][ and][ for exterior plastering work].
2.1.1.4 Galvanized Metal Plastering Base
NOTE: Specify galvanized metal plastering base for all exterior plastering
and for plastering interior areas subject to high moisture conditions such as
natatoriums and shower and laundry rooms.
Provide[ for exterior plastering work][ and][ for plastering room(s) [_____]][ in all locations].
2.1.2 Gypsum Lath
NOTE: Specify only for interior gypsum plastering work in relatively large,
flat areas. Do not use for curved areas or areas subject to high moisture conditions.
ASTM C 1063. Provide[ plain][ Type X (fire resistant)][ foil-backed] gypsum lath [9.53] [12.70] mm [3/8] [1/2]
inch thick.
2.1.3 Accessories
NOTE: Referenced ASTM standards permit accessories fabricated from:
1. ASTM C 1063:
- zinc coated (galvanized) steel
- zinc alloy
- rigid poly (vinyl chloride) (PVC) plastic
2. ASTM C 841:
- zinc coated (galvanized) steel
- paint coated steel
- rigid poly (vinyl chloride) (PVC) plastic
- clear plastic coated aluminum
If no exceptions are specified, these materials become Contractor options.
Include the last sentence, appropriately edited, to exclude any undesirable
options.
[ASTM C 1063. ][ASTM C 841. ] [ Provide only[ galvanized steel][ zinc alloy][ rigid poly (vinyl chloride) (PVC)
plastic][ clear plastic coated aluminum] accessories.]
2.2 ACCESS PANELS
NOTE: Detail fabrication of access panels larger than 600 by 900 mm 24 by 36
inches on project drawings.
Prefabricated steel units, size(s)[ as indicated][ [_____] by [_____] mm inches]. Fabricate frame of preformed
angle or channel with welded joints. Perforate wide leg or flange of frame section or extend frame section into
expanded metal wings to provide a key for the plaster. Cover shall be hinged or snap-on type with turn-latch
or spring catch.[ Provide access panels[ for room(s) [_____]] with a means for locking.] Fabricate access panels
not larger than 600 by 900 mm 24 by 36 inches from 1.8 mm thick 14 gage steel with frames not lighter than 1.5
mm thick 16 gage. Fabricate access panels larger than 600 by 900 mm 24 by 36 inches as indicated. Factory-prime
panels with rust-inhibitive paint.
PART 3 EXECUTION
3.1 INSPECTION
Verify that framing, furring and accessories are securely attached and of proper sizes and spacing necessary
to provide a suitable substrate to receive lath. Do not proceed with work until framing, furring and accessories
are acceptable to the Contracting Officer for application of lath.
3.2 INSTALLATION
3.2.1 Lathing Materials and Accessories
Install in accordance with[ ASTM C 1063 for portland cement-based plaster work][ and][ ASTM C 841 for gypsum
plaster work], except where indicated or specified otherwise herein.
3.2.1.1 Metal Plastering Base
Install[ where indicated][ on wood or metal studding, furring, joists, rafters, and similar framing members for
plastered walls, partitions, ceilings, and soffits][ to receive scratch coat for ceramic tile or terrazzo work][
on[ concrete][ and][ masonry] surfaces to receive plaster].
3.2.1.2 Metal Plaster Base with Paper Backing
Where used, lap joints to provide backing on backing and metal-on-metal. Lap backing not less than 25 mm one
inch. Lap backing so that water will flow to the exterior.
3.2.1.3 Gypsum Lath
Install[ where indicated][ on wood or metal studding, furring, joists, rafters and similar framing members for
plastered walls, partitions, ceilings, and soffits].
3.2.1.4 Control (Expansion and Contraction) Joints
a. For portland cement-based plaster (ceilings and walls), install to create panels no larger
than 10 square meters l00 square feet with no dimension exceeding 3150 mm 10 feet.
b. For unrestrained gypsum plaster ceilings install to create panels no larger than 250 square
meters 2,500 square feet with no dimension exceeding 15800 mm 50 feet. For gypsum plaster walls,
partitions and ceilings without perimeter relief install not more than 9000 mm 30 feet on centers
in either direction.
c. Install[ where indicated,] where expansion joints occur in the structural walls and ceilings
and where ceiling framing or furring changes direction. Terminate lath at each side of joint
and fasten joints securely to lath.
3.2.1.5 Unrestrained Ceilings
Furred or suspended ceilings constructed with[ gypsum plaster and larger than 250 square meters 2,500 square
feet in area or with any dimension exceeding 15,800 mm 50 feet][ or][ portland cement-based plaster] must be
unrestrained. Isolate ceiling lath and plaster from ceiling intersecting vertical surfaces with casing beads,
control joints, or similar devices designed to keep the ceiling isolated from the adjacent vertical surfaces
(walls, partitions, beams, and columns). Do not use corner reinforcement at the internal angle between the ceiling
and the vertical surfaces.
3.2.1.6 Plastering Beads
Install edge trim (casing bead)[ at the edges of plaster which abuts or adjoins an unplastered surface,][ on
each surface at the internal angle formed by load bearing and non-load bearing walls and partitions abutting
structural walls, columns, or floor-ceiling slabs,][ between concrete or terrazzo bases and the plaster above
them,][ on each side of the joint between walls or partitions constructed of dissimilar materials which require
plastering,][ and between plasters of a different composition]. Fill voids formed in corners with sealant. Install
corner beads at all vertical external corners of plaster walls.
3.2.2 Fire-Resistant Assemblies
NOTE: Coordinate with the preparer of the project drawings to ensure that UL
Design Number(s) or GA File Number(s) are indicated on the drawings for fire
resistant construction.
Wherever fire-resistant construction is indicated, provide all materials and application methods, including types
and spacing of fasteners, in accordance with the specifications contained in the[ UL Fire Resistance for the
Design Number(s) indicated][ or][ GA 600 for the File Number(s) indicated].
3.2.3 Access Panels
NOTE: Project drawings or specifications shall assure that the exact number
and location of access panels can be easily determined. Show this information
on the drawings. Coordinate with mechanical and electrical work to ensure adequate
access to mechanical and electrical systems. Do not install access panels in
fire rated walls or ceilings unless approved by the Engineering Field Division's
Fire Protection Engineer.
NOTE: Insert appropriate Section number and title in blank below using format
per UFC 1-300-02.
Install in suspended ceilings and plastered walls at locations[ indicated][ and][ specified in [_____]].
3.3 SCHEDULE
Some metric measurements in this section are based on mathematical conversion of inch-pound measurements, and
not on metric measurement commonly agreed to by the manufacturers or other parties. The inch-pound and metric
measurements are as follows:
PRODUCTS INCH-POUND METRIC
Access Panels 24 x 36 inches 600 x 900 mm
14 gage 1.8 mm
16 gage 1.5 mm