ASTM C1780-23a

Standard Practice for Installation Methods for Cement-based Adhered Masonry Veneer

SCOPE
1.1 This practice is intended to provide accepted procedures to designers and installers of cement-based adhered masonry veneer in residential and commercial construction. This information is meant to complement the specific installation instructions provided by manufacturers of cement-based adhered masonry veneers and recognized building codes, but is not meant to replace them. This practice does not address installation methods or techniques for all materials in the building envelope. This practice covers the installation of cement-based adhered masonry veneer units for application as adhered veneer to exterior and interior walls, columns, landscape structures and other structures suitable to receive adhered veneer. The units included in this practice are manufactured to meet the requirements of Specification C1670/C1670M or C1877. This practice is limited to the installation of units. This practice does not cover all flashing or moisture management requirements. Refer to the applicable building code and project documents for additional flashing and moisture management requirements.
Note 1: The National Concrete Masonry Association (NCMA) publication Installation Guide and Detailing Options for Compliance with ASTM C1780 for Adhered Manufactured Stone Veneer provides generally accepted methods and details for installation and flashing for manufactured stone veneer.
Note 2: This standard was developed for the installation of cement-based adhered veneer units manufactured from wet-cast concrete or dry-cast concrete. Refer to Guide C1242 for installation of adhered natural stone veneer.  
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 All workmanship and materials related to the installation of cement-based adhered masonry veneer units shall meet the requirements of the contract documents and building code having jurisdiction over the project.  
1.4 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.  
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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.2)  
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: Published
• Publication Date: 31-Jul-2023
• ICS: 91.080.30 - Masonry
• Technical Committee: C15 - Masonry – Manufactured Masonry Units, Mortars and Grouts
• Drafting Committee: C15.05 - Masonry Assemblies

Relations

• Refers: ASTM C1877-24 - Standard Specification for Adhered Concrete Masonry Units
• Effective Date: 15-Jan-2024
• Refers: ASTM C1232-23 - Standard Terminology for Masonry
• Effective Date: 15-Dec-2023
• Refers: ASTM C90-23 - Standard Specification for Loadbearing Concrete Masonry Units
• Effective Date: 01-Dec-2023
• Refers: ASTM C1384-23 - Standard Specification for Admixtures for Masonry Mortars
• Effective Date: 01-Dec-2023
• Refers: ASTM C1670/C1670M-23a - Standard Specification for Adhered Manufactured Stone Masonry Veneer Units
• Effective Date: 01-Dec-2023
• Refers: ASTM C1242-23c - Standard Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems
• Effective Date: 15-Nov-2023
• Refers: ASTM C926-23a - Standard Specification for Application of Portland Cement-Based Plaster
• Effective Date: 15-Nov-2023
• Refers: ASTM C1242-23b - Standard Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems
• Effective Date: 01-Nov-2023
• Refers: ASTM C1861-23a - Standard Specification for Lathing and Furring Accessories, and Fasteners, for Interior and Exterior Portland Cement-Based Plaster
• Effective Date: 01-Oct-2023
• Refers: ASTM C933-23 - Standard Specification for Welded Wire Lath
• Effective Date: 01-Oct-2023
• Refers: ASTM C1242-23a - Standard Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems
• Effective Date: 01-Oct-2023
• Refers: ASTM C482-20 - Standard Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste
• Effective Date: 01-Apr-2020
• Refers: ASTM C926-20 - Standard Specification for Application of Portland Cement-Based Plaster
• Effective Date: 01-Jan-2020
• Refers: ASTM C1877-19 - Standard Specification for Adhered Concrete Masonry Units
• Effective Date: 01-Dec-2019
• Refers: ASTM C1242-19a - Standard Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems
• Effective Date: 01-Nov-2019

Overview

ASTM C1780-23a: Standard Practice for Installation Methods for Cement-based Adhered Masonry Veneer provides a comprehensive guide for the installation of cement-based adhered masonry veneer in residential and commercial construction. This practice outlines recognized procedures to assist both designers and installers, ensuring durable and compliant applications on exterior and interior walls, columns, landscape structures, and other suitable substrates. The standard complements-but does not replace-manufacturer instructions and local building codes, focusing solely on the installation of veneer units manufactured according to ASTM specifications C1670/C1670M or C1877.

Key Topics

• Scope and Limitations: Covers installation of cement-based adhered veneer units to various building elements, but does not address all building envelope materials.
• Installation Procedures: Outlines substrate preparation, mortar selection, lath installation, application of water resistive barriers (WRB), and specific installation steps for different wall types and substrates.
• Materials: Specifies requirements for units, water resistive barriers, lath, cement boards, mortars, admixtures, bonding agents, and fasteners.
• Ambient Conditions: Addresses considerations for installation under hot, dry, cold, or freezing weather, stressing adherence to local building codes and manufacturer guidelines.
• Surface Preparation: Provides requirements for cleaning and preparation of masonry, wood/metal framing, existing stucco, and concrete surfaces prior to veneer installation.
• Application of Units: Details the process for setting units, joint treatment, pointing, finishing, and proper clearances for optimal performance and moisture management.
• Special Applications: Notes requirements for drainage wall systems and differences in interior versus exterior installations.

Applications

ASTM C1780-23a is essential for professionals involved in the design, selection, and installation of cement-based adhered masonry veneer systems across a variety of construction projects, including:

• Residential Construction: Enhances the appearance and durability of homes via stone or brick veneer facades and landscape features such as garden walls.
• Commercial Buildings: Provides architectural interest and longevity in office buildings, retail spaces, and institutional facilities.
• Interior and Exterior Walls: Guidance applies to both interior feature walls and exterior building envelopes, enabling consistent application methods across diverse settings.
• Landscape Structures: Suitable for free-standing or retaining walls, columns, and other outdoor structures that benefit from the aesthetic and protective qualities of adhered veneer.
• Renovation and Retrofits: Assists in evaluating and preparing existing stucco or masonry surfaces for new veneer installations, ensuring appropriate bonding and structural assessment.

Related Standards

For comprehensive project coordination and regulatory compliance, reference these additional standards:

• ASTM C1670/C1670M - Specification for Adhered Manufactured Stone Masonry Veneer Units
• ASTM C1877 - Specification for Adhered Concrete Masonry Units
• ASTM C270 & C1714/C1714M - Specifications for Mortar for Unit Masonry
• ASTM C847, C933, C1032, C1788 - Specifications for Lath Materials
• ASTM C1325 - Specification for Fiber-Mat Reinforced Cementitious Backer Units
• ICC-ES AC 376 - Acceptance Criteria for Reinforced Cementitious Sheets
• ANSI A118 Series - Specifications for Mortars for Tile Installations
• TMS 402/602 - Building Code Requirements and Specifications for Masonry Structures
• ASTM C1242 - Guidance for Installation of Adhered Natural Stone Veneer (for those using natural stone units)

Practical Value

With clear procedures for installation, material compatibility, and field-proven recommendations, ASTM C1780-23a promotes:

• Quality Workmanship: Ensures institutional quality and code compliance.
• Performance and Durability: Minimizes installation failures, optimizes moisture management, and extends service life of adhered veneer systems.
• Broad Applicability: Adapts to various climatic conditions and substrate types, supporting diverse project requirements.

By adhering to ASTM C1780-23a, professionals can achieve consistent, safe, and visually appealing results for cement-based adhered masonry veneer installations, enhancing both structural integrity and architectural appeal.

Keywords: ASTM C1780, cement-based adhered masonry veneer, masonry installation, veneer systems, installation practice, WRB, lath, mortar, stone veneer, construction standards.

Standards Content (Sample)

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.
Designation: C1780 − 23a
Standard Practice for
Installation Methods for Cement-based Adhered Masonry
Veneer
This standard is issued under the fixed designation C1780; 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* 1.4 The text of this standard references notes and footnotes
that provide explanatory material. These notes and footnotes
1.1 This practice is intended to provide accepted procedures
(excluding those in tables and figures) shall not be considered
to designers and installers of cement-based adhered masonry
as requirements of the standard.
veneer in residential and commercial construction. This infor-
1.5 This standard does not purport to address all of the
mation is meant to complement the specific installation instruc-
safety concerns, if any, associated with its use. It is the
tions provided by manufacturers of cement-based adhered
responsibility of the user of this standard to establish appro-
masonry veneers and recognized building codes, but is not
priate safety, health, and environmental practices and deter-
meant to replace them. This practice does not address instal-
mine the applicability of regulatory limitations prior to use.
lation methods or techniques for all materials in the building
(Warning—Fresh hydraulic cementitious mixtures are caustic
envelope. This practice covers the installation of cement-based
and may cause chemical burns to skin and tissue upon
adhered masonry veneer units for application as adhered
prolonged exposure. )
veneer to exterior and interior walls, columns, landscape
1.6 This international standard was developed in accor-
structures and other structures suitable to receive adhered
dance with internationally recognized principles on standard-
veneer. The units included in this practice are manufactured to
ization established in the Decision on Principles for the
meet the requirements of Specification C1670/C1670M or
Development of International Standards, Guides and Recom-
C1877. This practice is limited to the installation of units. This
mendations issued by the World Trade Organization Technical
practice does not cover all flashing or moisture management
Barriers to Trade (TBT) Committee.
requirements. Refer to the applicable building code and project
documents for additional flashing and moisture management
2. Referenced Documents
requirements.
2.1 ASTM Standards:
NOTE 1—The National Concrete Masonry Association (NCMA) publi-
C90 Specification for Loadbearing Concrete Masonry Units
cation Installation Guide and Detailing Options for Compliance with
ASTM C1780 for Adhered Manufactured Stone Veneer provides generally C270 Specification for Mortar for Unit Masonry
accepted methods and details for installation and flashing for manufac-
C482 Test Method for Bond Strength of Ceramic Tile to
tured stone veneer.
Portland Cement Paste
NOTE 2—This standard was developed for the installation of cement-
C847 Specification for Metal Lath
based adhered veneer units manufactured from wet-cast concrete or
C926 Specification for Application of Portland Cement-
dry-cast concrete. Refer to Guide C1242 for installation of adhered natural
stone veneer. Based Plaster
C932 Specification for Surface-Applied Bonding Com-
1.2 The values stated in inch-pound units are to be regarded
pounds for Exterior Plastering
as standard. The values given in parentheses are mathematical
C933 Specification for Welded Wire Lath
conversions to SI units that are provided for information only
C979/C979M Specification for Pigments for Integrally Col-
and are not considered standard.
ored Concrete
1.3 All workmanship and materials related to the installa-
C1032 Specification for Woven Wire Plaster Base
tion of cement-based adhered masonry veneer units shall meet
C1059/C1059M Specification for Latex Agents for Bonding
the requirements of the contract documents and building code
Fresh To Hardened Concrete
having jurisdiction over the project.
1 2
This practice is under the jurisdiction of ASTM Committee C15 on Manufac- Annual Book of ASTM Standards. Vol 04.01. See the section on Safety
tured Masonry Units and is the direct responsibility of Subcommittee C15.05 on Precautions in the Manual of Cement Testing.
Masonry Assemblies. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Aug. 1, 2023. Published August 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2013. Last previous edition approved in 2023 as C1780 – 23. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1780-23A. 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
C1780 − 23a
C1063 Specification for Installation of Lathing and Furring 3. Terminology
to Receive Interior and Exterior Portland Cement-Based
3.1 Definitions of Terms Specific to This Standard:
Plaster
3.1.1 cement-based adhered masonry veneer, n—the assem-
C1180 Terminology of Mortar and Grout for Unit Masonry
bly of thin cement-based masonry units adhered to a backing
C1232 Terminology for Masonry
with a cementitious mortar.
C1242 Guide for Selection, Design, and Installation of
3.1.1.1 Discussion—Thin cement-based masonry units in-
Dimension Stone Attachment Systems
clude those covered under Specifications C1670/C1670M and
C1325 Specification for Fiber-Mat Reinforced Cementitious
C1877.
Backer Units
3.1.2 back butter, v—the act of applying a setting bed mortar
C1384 Specification for Admixtures for Masonry Mortars
to the back of a masonry unit.
C1670/C1670M Specification for Adhered Manufactured
3.1.3 brown coat, n—in multiple coat stucco work, the
Stone Masonry Veneer Units
second coat, applied over the scratch coat.
C1714/C1714M Specification for Preblended Dry Mortar
Mix for Unit Masonry
3.1.4 drainage wall system, n—a system installation that
C1788 Specification for Non Metallic Plaster Bases (Lath)
creates a physical planar air gap between cladding system and
Used With Portland Cement Based Plaster in Vertical Wall
water resistive barrier.
Applications
3.1.5 foundation weep screed, n—an accessory used to
C1861 Specification for Lathing and Furring Accessories,
terminate cement-based adhered masonry veneer at the bottom
and Fasteners, for Interior and Exterior Portland Cement-
of exterior framed walls.
Based Plaster
3.1.5.1 Discussion—This accessory shall have a sloped,
C1877 Specification for Adhered Concrete Masonry Units
solid, or perforated, ground or screed flange to facilitate the
D226 Specification for Asphalt-Saturated Organic Felt Used
removal of moisture from the air gap and a vertical attachment
in Roofing and Waterproofing
flange not less than 3 ⁄2 in. (89 mm) long.
E2556/E2556M Specification for Vapor Permeable Flexible
3.1.6 full setting bed, n—mortar bed of specified thickness,
Sheet Water-Resistive Barriers Intended for Mechanical
covering the complete back of units and free of voids.
Attachment
3.1.7 scratch coat, n—the first coat of mortar or hydraulic
2.2 Other Standards:
cement based plaster applied to a base and then scratched to
TMS 402 Building Code Requirements for Masonry Struc-
create additional bonding area and mechanical interlock.
tures
TMS 602 Specification for Masonry Structures 3.1.8 setting bed, n—the mortar used to bond units to a
ICC ES AC 376 Acceptance Criteria for Reinforced Cemen- prepared surface or scratch coat.
titious Sheets Used as Wall and Ceiling Sheathing and
3.1.9 sheathed frame substrate, n—wood or metal/steel
Floor Underlayment
framing covered by a building code approved sheathing
2.3 ANSI Standards: material.
ANSI A118.1-2013.1 American National Standard Specifi-
3.1.10 thumb-print hard, adj—description of mortar joints
cations for Dry-Set Cement Mortar
to determine their readiness for tooling determined when the
ANSI A118.4-2013.1 American National Standard Specifi-
mortar will retain the imprint of a thumb but no mortar is
cations for Modified Dry-Set Cement Mortar
transferred to the thumb.
ANSI A118.15-2012.1 American National Standard Specifi-
3.1.11 tight fit joint, n—a joint created when units are
cations for Improved Modified Dry-Set Cement Mortar
installed with edges touching or less than ⁄8 in. (10 mm)
2.4 ICRI International Concrete Repair Institute:
distance between units.
No. 310.2–1997 Selecting and Specifying Concrete Surface
3.1.11.1 Discussion—Many units have varied and random
Preparation for Sealers, Coatings and Polymer Overlays
edges which make it impossible to define specific minimum or
(formerly No. 03732). Concrete Surface Profile Chips
maximum joint space.
2.5 National Concrete Masonry Association:
3.1.12 water resistive barrier (WRB), n—a material behind
Installation Guide and Detailing Options for Compliance
an exterior wall covering that is intended to resist liquid water
with ASTM C1780 for Adhered Manufactured Stone
that has penetrated the exterior covering from further intruding
Veneer
into the exterior wall assembly.
3.2 Refer to Terminology C1180 for additional terminology
4 for mortar and Terminology C1232 for additional terminology
Available from The Masonry Society (TMS), 105 South Sunset Street, Suite Q,
Longmont, CO 80501, http://www.masonrysociety.org. for masonry.
Available from ICC Evaluation Service, 3060 Saturn Street, Suite 100 Brea,
California 92821, http://www.iccsafe.org.
4. Materials
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org.
4.1 Cement-based adhered masonry veneer shall comply
Available from International Concrete Repair Institute (ICRI), 38800 Country
with the following requirements:
Club Drive Farmington Hills, MI 48331, http://www.icri.org.
4.1.1 Units shall comply with Specification C1670/C1670M
Available from National Concrete Masonry Association (NCMA), 13750
Sunrise Valley Drive Herndon, VA 20171, http://www.ncma.org. or C1877.
C1780 − 23a
4.2 Water Resistive Barrier shall comply with one of the 4.9 Water used for mixing mortar or dampening units,
following: scratch coat, or masonry surface shall be clean and free of
4.2.1 No. 15 felt complying with Specification D226, Type amounts of oils, acids, alkalies, salts, organic materials, or
1. other substances that are deleterious to mortar or any metal in
the wall.
4.2.2 Specification E2556/E2556M, Type I or II.
4.2.3 Other approved materials installed in accordance with
the manufacturer’s installation instructions (See Note 3). 5. Ambient Conditions
5.1 Hot and Dry Conditions—If the ambient conditions
NOTE 3—Other materials may be acceptable as the water resistive
barrier when approved by the building official and installed in accordance
exceed 100°F (37°C) or 90°F (32°C) with a wind velocity
with the manufacturer’s recommendations. Some (such as liquid-applied
greater than 8 mph (12.9 km/h) comply with the hot weather
or pre-coated sheathing) may only be acceptable for use as the inner layer
construction requirements of local building code, the recom-
of water resistive barrier. Climatic conditions should be taken into account
mendations of cement-based adhered masonry veneer unit
when specifying or selecting the water-resistive barrier to be installed.
manufacturer and hot weather construction provisions of TMS
NOTE 4—Some cement-based adhered masonry veneer systems utilize
a liquid-applied water resistive barrier as part of their proprietary systems.
602/ACI 530.1/ASCE 6. If there is a contradiction among
These materials are not discussed in this Practice, and users are encour-
documents, local building code shall prevail.
aged to perform their own evaluation of these proprietary systems for
5.1.1 When cement-based adhered masonry veneer is ap-
suitability.
plied in hot or dry weather, before applying mortar, moisten the
4.3 Lath shall comply with one of the following:
scratch coat with a fine spray of water or a wet brush to prevent
4.3.1 Expanded metal lath shall be corrosion resistant, shall
excessive absorption of water from the mortar. The scratch coat
2 2
have a minimum weight of 2.5 lb/yd (1.4 kg/m ) and shall
shall appear wet but without free water on the surface. Units
comply with the requirements of Specification C847.
shall also be moistened following the requirements of 7.2.1.
4.3.2 Woven wire mesh shall be corrosion resistant, shall be
5.2 Freezing or Low Temperatures—Accelerating admix-
a minimum of 18 gauge, and shall comply with the require-
tures shall comply with Specification C1384. Anti-freeze
ments of Specification C1032.
admixtures to lower freezing point of mortar shall not be used.
4.3.3 Welded wire lath shall be corrosion resistant and shall
Accelerating admixtures containing calcium chloride shall not
comply with Specification C933.
be used. If the ambient conditions are below 40°F (4°C), the
4.3.4 Non-metallic lath material shall be corrosion resistant
installation shall comply with the cold weather construction
and shall comply with Specification C1788.
provisions of TMS 602.
NOTE 5—It is acceptable to use lath materials that comply with 4.3 that
also provide a paper backing which complies with the requirements of 4.2.
6. Substrate/Surface Preparation
4.4 Cement Board—Cementitious Backer Units shall com-
6.1 The substrates and preparation that follow are typical
ply with Specification C1325. Cement boards shall have been
and field proven applications. Installation over any other
evaluated for interior or exterior use in accordance with
substrate requires the approval of the unit manufacturer.
ICC-ES Acceptance Criteria AC 376 by an ANSI-accredited
6.1.1 Alternative surface preparation shall be tested in
evaluation service.
accordance with Test Method C482 as modified by this
4.5 Mortar:
practice. The minimum shear bond strength between the unit
4.5.1 Mortar shall comply with one of the following: and the prepared surface shall be 50 psi (0.34 MPa). Refer to
4.5.1.1 Type N or Type S of Specification C270.
the modifications outlined in Appendix X1.
4.5.1.2 Type N or Type S of Specification C1714/C1714M.
6.2 Masonry:
4.5.1.3 ANSI A118.1-2013.1, ANSI A118.4-2013.1, or
6.2.1 Install units directly on masonry that is clean and free
ANSI A118.15-2012.1.
of paint, dirt, sealers, loose or spalling material.
6.2.2 All masonry surfaces that are dirty, painted, coated
NOTE 6—Mortar may be specified by the proportion method or the
property method of Specification C270.
with curing compounds or surface sealed, shall be cleaned by
power washing, sandblasting, beadblasting or appropriate sol-
4.5.2 Admixtures shall comply with Specification C1384.
vent to form a substrate suitable for bonding. If the surface
4.5.3 Bonding agents shall comply with Specification
condition cannot support direct application, install lath. If
C1059/C1059M or Specification C932.
masonry wall exhibits spalling, cracking or general
4.5.4 Mortar coloring pigments shall comply with Specifi-
deterioration, the wall shall be evaluated by the designer of
cation C979/C979M.
record for integrity before proceeding.
4.6 Lath fasteners shall comply with Specifications C1063
6.3 Wood/Metal Framing:
and C1861.
6.3.1 Water Resistive Barrier (WRB) Installation—Install
4.7 Foundation weep screed shall comply with Specification
two separate layers of WRB outboard of the sheathing
C1063.
material, in accordance with the WRB manufacturer’s instal-
4.8 Stucco system scratch or brown coat, when used as the lation instructions. Each layer is not required to be the same
cement-based adhered masonry veneer scratch coat, shall material. The WRB shall be integrated with all flashing
comply with Specification C926 up to the brown coat without materials in such a manner that prevents penetration of water
application of the finish coat. beyond the WRB. Overlaps in WRB shall be provided in
C1780 − 23a
NOTE 12—The purpose of a 48 hour cured scratch coat in the
accordance with the WRB manufacturer’s installation instruc-
applications outlined in 6.3.3 is to assure a firm surface to install the units.
tions. For D226 WRB materials, WRB shall overlap a mini-
These applications would otherwise not have a firm substrate to resist the
mum 6 in. (152 mm) at vertical joints and a minimum 2 in. (50
force of pressing units into place, leading to lath movement, c
...

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: C1780 − 23 C1780 − 23a
Standard Practice for
Installation Methods for Cement-based Adhered Masonry
Veneer
This standard is issued under the fixed designation C1780; 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 practice is intended to provide accepted procedures to designers and installers of cement-based adhered masonry veneer
in residential and commercial construction. This information is meant to complement the specific installation instructions provided
by manufacturers of cement-based adhered masonry veneers and recognized building codes, but is not meant to replace them. This
practice does not address installation methods or techniques for all materials in the building envelope. This practice covers the
installation of cement-based adhered masonry veneer units for application as adhered veneer to exterior and interior walls,
columns, landscape structures and other structures suitable to receive adhered veneer. The units included in this practice are
manufactured to meet the requirements of Specification C1670/C1670M or C1877. This practice is limited to the installation of
units. This practice does not cover all flashing or moisture management requirements. Refer to the applicable building code and
project documents for additional flashing and moisture management requirements.
NOTE 1—The National Concrete Masonry Association (NCMA) publication Installation Guide and Detailing Options for Compliance with ASTM C1780
for Adhered Manufactured Stone Veneer provides generally accepted methods and details for installation and flashing for manufactured stone veneer.
NOTE 2—This standard was developed for the installation of cement-based adhered veneer units manufactured from wet-cast concrete or dry-cast concrete.
Refer to Guide C1242 for installation of adhered natural stone veneer.
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 All workmanship and materials related to the installation of cement-based adhered masonry veneer units shall meet the
requirements of the contract documents and building code having jurisdiction over the project.
1.4 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns
to skin and tissue upon prolonged exposure. )
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.
This practice is under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and is the direct responsibility of Subcommittee C15.05 on Masonry
Assemblies.
Current edition approved Jan. 1, 2023Aug. 1, 2023. Published January 2023August 2023. Originally approved in 2013. Last previous edition approved in 20202023 as
C1780 – 20. DOI: 10.1520/C1780-22.23. DOI: 10.1520/C1780-23A.
Annual Book of ASTM Standards. Vol 04.01. See the section on Safety Precautions in the Manual of Cement Testing.
*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
C1780 − 23a
2. Referenced Documents
2.1 ASTM Standards:
C90 Specification for Loadbearing Concrete Masonry Units
C270 Specification for Mortar for Unit Masonry
C482 Test Method for Bond Strength of Ceramic Tile to Portland Cement Paste
C847 Specification for Metal Lath
C926 Specification for Application of Portland Cement-Based Plaster
C932 Specification for Surface-Applied Bonding Compounds for Exterior Plastering
C933 Specification for Welded Wire Lath
C979/C979M Specification for Pigments for Integrally Colored Concrete
C1032 Specification for Woven Wire Plaster Base
C1059/C1059M Specification for Latex Agents for Bonding Fresh To Hardened Concrete
C1063 Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster
C1180 Terminology of Mortar and Grout for Unit Masonry
C1232 Terminology for Masonry
C1242 Guide for Selection, Design, and Installation of Dimension Stone Attachment Systems
C1325 Specification for Fiber-Mat Reinforced Cementitious Backer Units
C1384 Specification for Admixtures for Masonry Mortars
C1670/C1670M Specification for Adhered Manufactured Stone Masonry Veneer Units
C1714/C1714M Specification for Preblended Dry Mortar Mix for Unit Masonry
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
C1877 Specification for Adhered Concrete Masonry Units
D226 Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing
E2556/E2556M Specification for Vapor Permeable Flexible Sheet Water-Resistive Barriers Intended for Mechanical Attachment
2.2 Other Standards:
TMS 402 Building Code Requirements for Masonry Structures
TMS 602 Specification for Masonry Structures
ICC ES AC 376 Acceptance Criteria for Reinforced Cementitious Sheets Used as Wall and Ceiling Sheathing and Floor
Underlayment
2.3 ANSI Standards:
ANSI A118.1-2013.1 American National Standard Specifications for Dry-Set Cement Mortar
ANSI A118.4-2013.1 American National Standard Specifications for Modified Dry-Set Cement Mortar
ANSI A118.15-2012.1 American National Standard Specifications for Improved Modified Dry-Set Cement Mortar
2.4 ICRI International Concrete Repair Institute:
No. 310.2–1997 Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings and Polymer Overlays (formerly
No. 03732). Concrete Surface Profile Chips
2.5 National Concrete Masonry Association:
Installation Guide and Detailing Options for Compliance with ASTM C1780 for Adhered Manufactured Stone Veneer
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 cement-based adhered masonry veneer, n—the assembly of thin cement-based masonry units adhered to a backing with a
cementitious mortar.
3.1.1.1 Discussion—
Thin cement-based masonry units include those covered under Specifications C1670/C1670M and C1877.
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.
Available from The Masonry Society (TMS), 105 South Sunset Street, Suite Q, Longmont, CO 80501, http://www.masonrysociety.org.
Available from ICC Evaluation Service, 3060 Saturn Street, Suite 100 Brea, California 92821, http://www.iccsafe.org.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from International Concrete Repair Institute (ICRI), 38800 Country Club Drive Farmington Hills, MI 48331, http://www.icri.org.
Available from National Concrete Masonry Association (NCMA), 13750 Sunrise Valley Drive Herndon, VA 20171, http://www.ncma.org.
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3.1.2 back butter, v—the act of applying a setting bed mortar to the back of a masonry unit.
3.1.3 brown coat, n—in multiple coat stucco work, the second coat, applied over the scratch coat.
3.1.4 drainage wall system, n—a system installation that creates a physical planar air gap between cladding system and water
resistive barrier.
3.1.5 foundation weep screed, n—an accessory used to terminate cement-based adhered masonry veneer at the bottom of exterior
framed walls.
3.1.5.1 Discussion—
This accessory shall have a sloped, solid, or perforated, ground or screed flange to facilitate the removal of moisture from the air
gap and a vertical attachment flange not less than 3 ⁄2 in. (89 mm) long.
3.1.6 full setting bed, n—mortar bed of specified thickness, covering the complete back of units and free of voids.
3.1.7 scratch coat, n—the first coat of mortar or hydraulic cement based plaster applied to a base and then scratched to create
additional bonding area and mechanical interlock.
3.1.8 setting bed, n—the mortar used to bond units to a prepared surface or scratch coat.
3.1.9 sheathed frame substrate, n—wood or metal/steel framing covered by a building code approved sheathing material.
3.1.10 thumb-print hard, adj—description of mortar joints to determine their readiness for tooling determined when the mortar will
retain the imprint of a thumb but no mortar is transferred to the thumb.
3.1.11 tight fit joint, n—a joint created when units are installed with edges touching or less than ⁄8 in. (10 mm) distance between
units.
3.1.11.1 Discussion—
Many units have varied and random edges which make it impossible to define specific minimum or maximum joint space.
3.1.12 water resistive barrier (WRB), n—a material behind an exterior wall covering that is intended to resist liquid water that has
penetrated the exterior covering from further intruding into the exterior wall assembly.
3.2 Refer to Terminology C1180 for additional terminology for mortar and Terminology C1232 for additional terminology for
masonry.
4. Materials
4.1 Cement-based adhered masonry veneer shall comply with the following requirements:
4.1.1 Units shall comply with Specification C1670/C1670M or C1877.
4.2 Water Resistive Barrier shall comply with one of the following:
4.2.1 No. 15 felt complying with Specification D226, Type 1.
4.2.2 Specification E2556/E2556M, Type I or II.
4.2.3 Other approved materials installed in accordance with the manufacturer’s installation instructions (See Note 3).
NOTE 3—Other materials may be acceptable as the water resistive barrier when approved by the building official and installed in accordance with the
manufacturer’s recommendations. Some (such as liquid-applied or pre-coated sheathing) may only be acceptable for use as the inner layer of water
resistive barrier. Climatic conditions should be taken into account when specifying or selecting the water-resistive barrier to be installed.
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NOTE 4—Some cement-based adhered masonry veneer systems utilize a liquid-applied water resistive barrier as part of their proprietary systems. These
materials are not discussed in this Practice, and users are encouraged to perform their own evaluation of these proprietary systems for suitability.
4.3 Lath shall comply with one of the following:
2 2
4.3.1 Expanded metal lath shall be corrosion resistant, shall have a minimum weight of 2.5 lb/yd (1.4 kg/m ) and shall comply
with the requirements of Specification C847.
4.3.2 Woven wire mesh shall be corrosion resistant, shall be a minimum of 18 gauge, and shall comply with the requirements of
Specification C1032.
4.3.3 Welded wire lath shall be corrosion resistant and shall comply with Specification C933.
4.3.4 Non-metallic lath material shall be corrosion resistant and shall comply with Specification C1788.
NOTE 5—It is acceptable to use lath materials that comply with 4.3 that also provide a paper backing which complies with the requirements of 4.2.
4.4 Cement Board—Cementitious Backer Units shall comply with Specification C1325. Cement boards shall have been evaluated
for interior or exterior use in accordance with ICC-ES Acceptance Criteria AC 376 by an ANSI-accredited evaluation service.
4.5 Mortar:
4.5.1 Mortar shall comply with one of the following:
4.5.1.1 Type N or Type S of Specification C270.
4.5.1.2 Type N or Type S of Specification C1714/C1714M.
4.5.1.3 ANSI A118.1-2013.1, ANSI A118.4-2013.1, or ANSI A118.15-2012.1.
NOTE 6—Mortar may be specified by the proportion method or the property method of Specification C270.
4.5.2 Admixtures shall comply with Specification C1384.
4.5.3 Bonding agents shall comply with Specification C1059/C1059M or Specification C932.
4.5.4 Mortar coloring pigments shall comply with Specification C979/C979M.
4.6 Lath fasteners shall comply with Specifications C1063 and C1861.
4.7 Foundation weep screed shall comply with Specification C1063.
4.8 Stucco system scratch or brown coat, when used as the cement-based adhered masonry veneer scratch coat, shall comply with
Specification C926 up to the brown coat without application of the finish coat.
4.9 Water used for mixing mortar or dampening units, scratch coat, or masonry surface shall be clean and free of amounts of oils,
acids, alkalies, salts, organic materials, or other substances that are deleterious to mortar or any metal in the wall.
5. Ambient Conditions
5.1 Hot and Dry Conditions—If the ambient conditions exceed 100°F (37°C) or 90°F (32°C) with a wind velocity greater than
8 mph (12.9 km/h) comply with the hot weather construction requirements of local building code, the recommendations of
cement-based adhered masonry veneer unit manufacturer and hot weather construction provisions of TMS 602/ACI 530.1/ASCE
6. If there is a contradiction among documents, local building code shall prevail.
5.1.1 When cement-based adhered masonry veneer is applied in hot or dry weather, before applying mortar, moisten the scratch
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coat with a fine spray of water or a wet brush to prevent excessive absorption of water from the mortar. The scratch coat shall
appear wet but without free water on the surface. Units shall also be moistened following the requirements of 7.2.1.
5.2 Freezing or Low Temperatures—Accelerating admixtures shall comply with Specification C1384. Anti-freeze admixtures to
lower freezing point of mortar shall not be used. Accelerating admixtures containing calcium chloride shall not be used. If the
ambient conditions are below 40°F (4°C), the installation shall comply with the cold weather construction provisions of TMS 602.
6. Substrate/Surface Preparation
6.1 The substrates and preparation that follow are typical and field proven applications. Installation over any other substrate
requires the approval of the unit manufacturer.
6.1.1 Alternative surface preparation shall be tested in accordance with Test Method C482 as modified by this practice. The
minimum shear bond strength between the unit and the prepared surface shall be 50 psi (0.34 MPa). Refer to the modifications
outlined in Appendix X1.
6.2 Masonry:
6.2.1 Install units directly on masonry that is clean and free of paint, dirt, sealers, loose or spalling material.
6.2.2 All masonry surfaces that are dirty, painted, coated with curing compounds or surface sealed, shall be cleaned by power
washing, sandblasting, beadblasting or appropriate solvent to form a substrate suitable for bonding. If the surface condition cannot
support direct application, install lath. If masonry wall exhibits spalling, cracking or general deterioration, the wall shall be
evaluated by the designer of record for integrity before proceeding.
6.3 Wood/Metal Framing:
6.3.1 Water Resistive Barrier (WRB) Installation—Install two separate layers of WRB outboard of the sheathing material, in
accordance with the WRB manufacturer’s installation instructions. Each layer is not required to be the same material. The WRB
shall be integrated with all flashing materials in such a manner that prevents penetration of water beyond the WRB. Overlaps in
WRB shall be provided in accordance with the WRB manufacturer’s installation instructions. For D226 WRB materials, WRB
shall overlap a minimum 6 in. (152 mm) at vertical joints and a minimum 2 in. (50 mm) at horizontal joints and shall be applied
in shingle fashion. WRB fasteners shall be spaced in accordance with the water resistive barrier manufacturer’s installation
instructions.
NOTE 7—Some building code jurisdictions allow a single layer WRB
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