ASTM C847-18

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C847 − 14a C847 − 18
Standard Specification for
Metal Lath
This standard is issued under the fixed designation C847; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1 3
1.1 This specification covers sheet lath, expanded metal lath, diamond mesh, flat and self-furring, and rib metal lath, ⁄8 and ⁄8
in. (3.2 and 9.6 mm), all with or without backing factory-attached water-resistive barrier 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.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A653/A653M Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the
Hot-Dip Process
E2556/E2556M Specification for Vapor Permeable Flexible Sheet Water-Resistive Barriers Intended for Mechanical Attachment
3. Material
3.1 Metal lath shall be fabricated from cold-rolled carbon steel sheet of commercial quality conforming to Specification
A653/A653M. Galvanized metal lath shall have a G60 coating in accordance with Specification A653/A653M.
3.2 Water-Resistive Barrier—Compliant with Federal Specification UU-B-790a, or Specification E2556/E2556M.
3.3 Backing Factory-attached water-resistive barrier shall be attached to the lath sufficiently enough to prevent accidental
removal during shipping, handling, or installation. Attachment of backing water-resistive barrier shall also allow lapping of metal
to metal and backing to backing, water-resistive barrier to water-resistive barrier, 1 in. (25.4 mm) on the ends and ⁄2 in. (12.7 mm)
on the sides.
4. Dimensions, Mass, and Permissible Variations
4.1 Thickness—The nominal thickness of diamond mesh and flat rib metal lath shall be ⁄8 in. (3.2 mm). The nominal thickness
3 5
of other rib metal lath shall be as designated, ⁄8 in. (9.6 mm). The nominal thickness of self-furring diamond mesh shall be ⁄16
in. (7.9 mm).
4.2 Width—The minimum width of metal lath shall be 27 in. (686 mm).
4.3 Length—The minimum length of metal lath shall be 97 in. (2464 mm).
4.4 Weight—The weight of metal lath shall be as follows:
4.4.1 U.S. Weights:
This specification is under the jurisdiction of ASTM Committee C11 on Gypsum and Related Building Materials and Systems and is the direct responsibility of
Subcommittee C11.02 on Specifications and Test Methods for Accessories and Related Products.
Current edition approved Nov. 1, 2014Oct. 1, 2018. Published November 2014October 2018. Originally approved in 1977. Last previous edition approved in 2014 as
C847 – 14.C847 – 14a. DOI: 10.1520/C0847-14A.10.1520/C0847-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C847 − 18
2 2
Type: Weight, lb/yd (kg/m )
Diamond mesh 2.5 (1.4); 3.4 (1.8)
Flat rib 1.8 (1.0); 2.75 (1.5); 3.4 (1.8)
⁄8-in. rib 3.4 (1.8); 4.0 (2.1)
4.4.2 Canadian Weights:
2 2
Type: Weight, lb/yd (kg/m )
Diamond mesh 2.5 (1.4); 3.0 (1.6); 3.4 (1.8)
Flat rib 1.8 (1.0); 2.5 (1.4); 3.0 (1.6)
⁄8-in. rib 3.0 (1.6); 3.5 (1.9); 4.0 (2.1)
4.5 Permissible Variations—The permissible variations shall be as follows:
4.5.1 Thickness, 6 ⁄64 in. (0.4 mm).
4.5.2 Width, −0 in., + ⁄8 in. (9.5 mm).
4.5.3 Length, −0 in., +1 ⁄2 in. (38.1 mm).
4.5.4 Weight, 610 %.
5. Finish
5.1 Metal lath shall be fabricated from hot-dipped galvanized steel.
6. Weight Test
6.1 Significance and Use—This test method provides a procedure for measuring the weight of a single sheet of metal lath. It
shall be used to determine compliance with this specification. The degree of performance of this test method with service
performance has not been determined.
6.2 Apparatus:
6.2.1 Scale, capable of weighing in increments of 0.1 lb (0.05 kg) or 1 oz (28 g).
6.2.2 Tape Measure, capable of measuring in increments of ⁄16 in. (1.6 mm).
6.3 Materials shall satisfy the following:
6.3.1 Metal Lath—Specification C847.
6.4 Sampling—One sheet shall be selected from each bundle or package, but not more than five sheets from any one shipment
for testing.
6.5 Specimen Preparation:
6.5.1 Measure and record the width and length of each specimen.
NOTE 1—For paper-backed lath, remove the paper lath with a factory-attached water-resisti
...