ASTM C1787-20

Standard Specification for Installation of Non Metallic Plaster Bases (Lath) Used with Portland Cement Based Plaster in Vertical Wall Applications

ABSTRACT
This specification describes the minimum requirements for the installation of non-metallic plaster bases used with portland cement-based plaster in vertical wall applications. In cases where a fire resistance rating is required for plastered assemblies and constructions, the construction details shall conform to reports of fire tests of assemblies that have satisfied the requirements of the fire rating imposed. The standard defines the requirements with respect to delivery and storage of materials, coordination and scheduling of installation, application of accessories, and application of non-metallic plaster bases.
SCOPE
1.1 This specification applies to the minimum installation requirements for non metallic plaster bases used with Portland cement based plaster in vertical wall applications.  
1.2 Where a fire resistance rating is required for plastered assemblies and constructions, details of construction shall be in accordance with reports of fire tests of assemblies that have met the requirements of the fire rating imposed.  
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.4 Details of construction for a specific assembly to achieve the required fire resistance, sound or acoustic rating shall be obtained from reports of fire-resistance tests, engineering evaluations, or listings from recognized fire testing, sound or acoustic laboratories.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

General Information

• Status: Historical
• Publication Date: 30-Sep-2020
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C11 - Gypsum and Related Building Materials and Systems
• Drafting Committee: C11.03 - Specifications for the Application of Gypsum and Other Products in Assemblies

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1787 − 20
Standard Specification for
Installation of Non Metallic Plaster Bases (Lath) Used with
Portland Cement Based Plaster in Vertical Wall
1
Applications
This standard is issued under the fixed designation C1787; 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.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This specification applies to the minimum installation
C926 Specification for Application of Portland Cement-
requirements for non metallic plaster bases used with Portland
Based Plaster
cement based plaster in vertical wall applications.
C954 Specification for Steel Drill Screws for the Application
1.2 Where a fire resistance rating is required for plastered
of Gypsum Panel Products or Metal Plaster Bases to Steel
assemblies and constructions, details of construction shall be in
Studs from 0.033 in. (0.84 mm) to 0.112 in. (2.84 mm) in
accordance with reports of fire tests of assemblies that have
Thickness
met the requirements of the fire rating imposed.
C1063 Specification for Installation of Lathing and Furring
to Receive Interior and Exterior Portland Cement-Based
1.3 Units—The values stated in either SI units or inch-
Plaster
pound units are to be regarded separately as standard. The
C1788 Specification for Non Metallic Plaster Bases (Lath)
values stated in each system are not necessarily exact equiva-
Used with Portland Cement Based Plaster in Vertical Wall
lents; therefore, to ensure conformance with the standard, each
Applications
system shall be used independently of the other, and values
C1861 Specification for Lathing and Furring Accessories,
from the two systems shall not be combined.
and Fasteners, for Interior and Exterior Portland Cement-
Based Plaster
1.4 Details of construction for a specific assembly to
E631 Terminology of Building Constructions
achieve the required fire resistance, sound or acoustic rating
shall be obtained from reports of fire-resistance tests, engineer-
3. Terminology
ing evaluations, or listings from recognized fire testing, sound
or acoustic laboratories. 3.1 Definitions:
3.1.1 For definitions of terms used in this specification, refer
1.5 This standard does not purport to address all of the
to Terminology E631.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 Portland cement based plaster, n—see Specification
priate safety, health, and environmental practices and deter-
C926.
mine the applicability of regulatory limitations prior to use.
3.2.2 non metallic plaster base (lath), n—material used as a
1.6 This international standard was developed in accor-
base for Portland cement based plaster that is self furred and
dance with internationally recognized principles on standard-
meets or exceeds the requirements set forth in Specification
ization established in the Decision on Principles for the
C1788.
Development of International Standards, Guides and Recom-
3.2.3 framing member, n—see Specification C1063.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4. Delivery and Storage of Materials
4.1 All materials shall be delivered in original, undamaged
containers.
1
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 C11.03 on Specifications for the Application of Gypsum and Other
2
Products in Assemblies. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2020. Published October 2020. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2014. Last previous edition approved in 2019 as C1787 – 14 (2019). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/C1787-20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C1787 − 20
4.2 Store materials inside or under cover protected from 8.3.1 Non metallic plaster base shall be attached to framing
weather. members spaced not more than 16 in. (406 mm) on center with
attachments spaced not more than 7 in. (178 mm) on center
5. Coordination and Scheduling
along supports.
8.3.2 Non metallic plaster base shall be attached with
5.1 Coordinate and schedule installation of non metallic
manufacturer recommended fasteners. Staples
...

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: C1787 − 14 (Reapproved 2019) C1787 − 20
Standard Specification for
Installation of Non Metallic Plaster Bases (Lath) Used with
Portland Cement Based Plaster in Vertical Wall
1
Applications
This standard is issued under the fixed designation C1787; 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.
1. Scope
1.1 This specification applies to the minimum installation requirements for non metallic plaster bases used with portlandPortland
cement based plaster in vertical wall applications.
1.2 Where a fire resistance rating is required for plastered assemblies and constructions, details of construction shall be in
accordance with reports of fire tests of assemblies that have met the requirements of the fire rating imposed.
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in
each system mayare not benecessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be
used independently of the other. Combiningother, and values from the two systems may result in non-conformance with the
standard.shall not be combined.
1.4 Details of construction for a specific assembly to achieve the required fire resistance, sound or acoustic rating shall be obtained
from reports of fire-resistance tests, engineering evaluations, or listings from recognized fire testing, sound or acoustic laboratories.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 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
2.1 ASTM Standards:
C926 Specification for Application of Portland Cement-Based Plaster
C954 Specification for Steel Drill Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Steel Studs
from 0.033 in. (0.84 mm) to 0.112 in. (2.84 mm) in Thickness
C1063 Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster
1
This test method specification is under the jurisdiction of ASTM Committee C11 on Gypsum and Related Building Materials and Systems and is the direct responsibility
of Subcommittee C11.03 on Specifications for the Application of Gypsum and Other Products in Assemblies.
Current edition approved March 1, 2019Oct. 1, 2020. Published March 2019October 2020. Originally approved in 2014. Last previous edition approved in 20142019 as
C1787 – 14.C1787 – 14 (2019). DOI: 10.1520/C1787-14R19.10.1520/C1787-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C1787 − 20
E631 Terminology of Building Constructions
C1788 Specification for Non Metallic Plaster Bases (Lath) Used with Portland Cement Based Plaster in Vertical Wall
Applications
C1861 Specification for Lathing and Furring Accessories, and Fasteners, for Interior and Exterior Portland Cement-Based
Plaster
E631 Terminology of Building Constructions
3. Terminology
3.1 Definitions—For definitions of terms used in these test methods, See Terminology E631.
3.1 Definitions:
3.1.1 For definitions of terms used in this specification, refer to Terminology E631.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 portlandPortland cement based plaster, n—see Specification C926.
3.2.2 non metallic plaster base (lath), n—material used as a base for portlandPortland cement based plaster that is self furred and
meets or exceeds the requirements set forth in Specification C1788.
3.2.3 framing member, n—see Specification C10
...