ASTM C1516-05(2023)
(Practice)Standard Practice for Application of Direct-Applied Exterior Finish Systems
Standard Practice for Application of Direct-Applied Exterior Finish Systems
SIGNIFICANCE AND USE
4.1 This practice provides minimum requirements for the application of Direct-applied Exterior Finish Systems. The requirements for materials, mixtures, and details shall be contained in the project plans and specifications.
SCOPE
1.1 This practice covers the minimum requirements and procedures for field application of Direct-applied Exterior Finish Systems (DEFS). Direct-applied exterior finish systems are coating systems applied over various substrates with non-metallic reinforcing mesh, in which the base coat ranges from not less than 1/16 in. (1.6 mm) to 3/32 in. (2.4 mm) in dry thickness, depending on the mass of the reinforcing mesh. This base coat is subsequently covered with a finish coat that is available in a variety of textures and colors.
1.2 The values stated in inch-pound units are to be regarded as the standard. The metric values given in parentheses are approximate and are provided for information purposes only.
1.3 This standard may involve hazardous materials, operations, and equipment. 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.
1.4 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
Relations
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: C1516 − 05 (Reapproved 2023)
Standard Practice for
Application of Direct-Applied Exterior Finish Systems
This standard is issued under the fixed designation C1516; 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 to Receive Interior and Exterior Portland Cement-Based
Plaster
1.1 This practice covers the minimum requirements and
C1177/C1177M Specification for Glass Mat Gypsum Sub-
procedures for field application of Direct-applied Exterior
strate for Use as Sheathing
Finish Systems (DEFS). Direct-applied exterior finish systems
C1186 Specification for Flat Fiber-Cement Sheets
are coating systems applied over various substrates with
C1278/C1278M Specification for Fiber-Reinforced Gypsum
non-metallic reinforcing mesh, in which the base coat ranges
Panel
1 3
from not less than ⁄16 in. (1.6 mm) to ⁄32 in. (2.4 mm) in dry
C1325 Specification for Fiber-Mat Reinforced Cementitious
thickness, depending on the mass of the reinforcing mesh. This
Backer Units
base coat is subsequently covered with a finish coat that is
E1825 Guide for Evaluation of Building Exterior Enclosure
available in a variety of textures and colors.
Materials, Products, and Systems
1.2 The values stated in inch-pound units are to be regarded
as the standard. The metric values given in parentheses are
3. Terminology
approximate and are provided for information purposes only.
3.1 Definitions used in this standard shall be in accordance
1.3 This standard may involve hazardous materials,
with Terminology C11.
operations, and equipment. This standard does not purport to
3.2 Definitions of Terms Specific to This Standard:
address all of the safety concerns, if any, associated with its
3.2.1 accessories, n—preformed metal, fiberglass or plastic
use. It is the responsibility of the user of this standard to
members used to form corners, edges, control joints, or
establish appropriate safety, health, and environmental prac-
decorative effects.
tices and determine the applicability of regulatory limitations
prior to use. 3.2.2 back wrapping, n—a deprecated term. See wrap.
1.4 This international standard was developed in accor-
3.2.3 base coat, n—a material, either factory or field-mixed,
dance with internationally recognized principles on standard-
used to cover the substrate and to encapsulate the reinforcing
ization established in the Decision on Principles for the
mesh.
Development of International Standards, Guides and Recom-
3.2.4 cold joint, n—the visible junction in an exterior finish.
mendations issued by the World Trade Organization Technical
3.2.5 cure, v—to develop the ultimate properties of a wet
Barriers to Trade (TBT) Committee.
state material by a chemical process.
2. Referenced Documents
3.2.6 dry, v—to develop the ultimate properties of a wet
state material solely by evaporation of volatile ingredients.
2.1 ASTM Standards:
3.2.7 durability, n—the capability of a building, assembly,
C11 Terminology Relating to Gypsum and Related Building
Materials and Systems component, product, or construction to maintain serviceability
over not less than a specified time.
C1063 Specification for Installation of Lathing and Furring
3.2.8 embed, v—to encapsulate a non-metallic reinforcing
mesh in either the joint compound or exterior finish.
This practice is under the jurisdiction of ASTM Committee C11 on Gypsum
3.2.9 expansion joint, n—a structural separation between
and Related Building Materials and Systems and is the direct responsibility of
building elements that allows independent movement without
Subcommittee C11.05 on Application of Exterior Insulating and Finish Systems and
Related Products. damage to the assembly.
Current edition approved March 1, 2023. Published March 2023. Originally
3.2.10 factory mixed, n—a material that is prepared at the
approved in 2002. Last previous edition approved in 2017 as C1516 – 05 (2017).
point of manufacture and is ready to use without the addition
DOI: 10.1520/C1516-05R23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of other materials, except possibly water to adjust consistency.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.2.11 field mix, n—a material that is mixed in the field with
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. other components, water, or both.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1516 − 05 (2023)
3.2.12 finish coat, n—the final wet state material, that 5. Delivery of Materials
provides color or additional texture, applied over the reinforced
5.1 All materials shall be delivered in packages, containers,
base coat.
or bundles with the identification and markings intact.
3.2.13 flash set (quick set), n—the early hardening or
stiffness in the working characteristics of a Portland-cement
6. Inspection
paste, mortar, or concrete, usually with the evolution of
6.1 Inspection of the materials shall be agreed upon between
considerable heat; stiffness cannot be dispelled nor the plastic-
the purchaser and the supplier as part of the purchase agree-
ity regained by further mixing without addition of water; also
ment.
known as “quick set.”
3.2.14 framing member, n—studs, joist, runners (tracks),
7. Rejection
bridging, bracing, and related accessories manufactured or
7.1 Materials that are damaged, frozen, or in any way
supplied in wood or hot or cold formed steel.
defective shall not be used. Rejection of materials shall be
3.2.15 initial grab, n—the ability of a wet state material to
promptly reported verbally to the producer and immediately
remain in place initially after it has been applied.
reported in writing. The notice of rejection shall contain a
statement documenting the basis for material rejection.
3.2.16 initial set, n—a time related set caused by the
hydration process.
8. Certification
3.2.17 lamina, n—composite of base coat, reinforcement,
8.1 When specified in the contract documents, the exterior
and finish coat.
finish producer shall furnish a report certifying that the
3.2.18 mechanical fastener, n—corrosion resistant compo-
materials are in conformance with product and material stan-
nent used to attach the substrate to the framing member.
dards and contract documents.
3.2.19 reinforcing mesh, n—a non-metallic component of
8.2 The substrate panels shall be marked as complying with
the DEFS encapsulated in the base coat to strengthen the
the applicable product specification.
system.
3.2.19.1 Discussion—Non-metallic reinforcing mesh is
9. Storage of Materials
available in various weights to achieve different levels of
9.1 All materials shall be kept dry by storage under cover
impact and stress resistance.
and protected from the weather.
3.2.20 pot life, n—the duration of time that the wet state
9.1.1 When outside storage is required, substrate panels
material remains workable after it has been mixed.
shall be stacked flat with care taken to avoid damage to edges,
3.2.21 primers, n—liquid coatings applied to improve the ends, or surfaces.
adhesion of the DEFS to the substrate.
9.1.2 All other DEFS components shall be stacked off the
ground, supported on a level platform and protected from the
3.2.21.1 Discussion—Primers are sometimes applied to im-
direct sunlight, weather, surface contamination or physical
prove the water resistance of cementitious base coats.
damage in accordance with the DEFS producer’s written
3.2.22 reinforced base coat, n—base coat that has been
instructions.
reinforced with a non-metallic reinforcing mesh.
9.2 Materials shall be protected from exposure to tempera-
3.2.23 substrate, n—surface to which the DEFS is applied.
tures less than 40 °F (4 °C), unless otherwise specified by the
3.2.24 surface sealer, n—material used to enhance weather manufacturer.
resistance.
9.3 Portland Cement shall be kept dry until ready for use. It
3.2.25 temper, v—to bring to a workable state by adding
shall be kept off the ground, under cover and away from damp
water.
walls and surfaces.
3.2.26 texture, n—any surface appearance as contrasted to a
10. Environmental Conditions
smooth surface.
10.1 Cold Weather Conditions:
3.2.27 wet edge, n—the leading edge of a continuously
10.1.1 Wet materials shall not be applied when the tempera-
applied wet state material.
ture is less than 40 °F (4 °C) unless temporary heat and
3.2.28 wet state materials, n—the adhesive, base coat and
enclosures are provided to maintain a minimum temperature of
finish coat components applied in liquid or semi-liquid state.
40 °F (4 °C) for a minimum period of not less than 24 h before,
during and after application or unless otherwise specified by
4. Significance and Use
the manufacturer.
4.1 This practice provides minimum requirements for the 10.1.2 Materials shall not be applied to a base containing
application of Direct-applied Exterior Finish Systems. The frost. Substrate surface temperature shall be not less than 40 °F
requirements for materials, mixtures, and details shall be (4 °C) unless otherwise specified by the manufacturer. Mix-
contained in the project plans and specifications. tures for application shall not contain any frozen ingredients.
C1516 − 05 (2023)
11. Assessment of Condition of Substrates to Receive 11.7 Substrate Condition—There shall be no visible water.
Direct Exterior and Finish Systems
11.8 If furring or accessories are used, they shall be installed
11.1 The substrate shall be as required by the project plans in conformance with Specification C1063.
and specifications and as specified by the DEFS producer for
11.8.1 These members shall be properly attached, straight,
the particular system.
and true unless required by the system design.
11.8.2 All accessories shall be free of rust, oil, or other
11.2 The substrate shall be inspected by the applicator and
foreign matter or contaminants, which cause bond failure or
general contractor to ensure that it meets the project plans and
unsightly discoloration.
specifications and the requirements of 11.3 – 11.8.2.
11.3 Sheathing materials shall be inspected to ensure that:
12. Reinforced Base Coat Application
11.3.1 The specified sheathing thickness has been installed
12.1 Inspect the substrate panel surface to ensure that it is
for the stud spacing used.
clean, dry, and free of all foreign materials and damage of any
11.3.2 Fastener type and fastener spacing are as specified.
type. Substrate panel planar irregularities of more than ⁄16 in.
11.3.3 Water-resistant exterior fiber-reinforced gypsum
(1.6 mm) shall be corrected. All panel joints shall be tightly
sheathing panels complying with Specification C1278/
abutted or shall be filled with recommended joint bedding
C1278M shall be installed in accordance with the sheet
material.
producer’s written installation instructions, which include de-
tails of framing type and spacing, fastener type and spacing,
12.2 Base Coat Preparation—All materials requiring field
and sheet orientation and spacing.
preparation shall be mixed in accordance with the DEFS
11.3.4 Glass mat gypsum sheathing complying with Speci-
producer’s specifications.
fication C1177/C1177M, shall be installed in accordance with
12.3 Base Coat Application—The prepared base coat shall
the sheet producer’s written installation instructions, which
be uniformly spread over the entire surface of the substrate
include details of framing type and spacing, fastener type and
panel.
spacing, and sheet orientation and spacing.
12.4 Reinforcing Mesh—The single layer reinforcing mesh,
11.3.5 Fiber-cement sheets complying with Specification
C1186, Type A, shall be installed in accordance with the sheet when specified, shall be fully encapsulated in the field of the
wall, at corners, edges, and joints. Trowel from the center to the
producer’s written installation instructions, which include de-
tails of framing type and spacing, fastener type and spacing, edge of the reinforcing mesh to avoid wrinkles. The single
layer reinforcing mesh shall be continuous at all corners.
and sheet orientation and spacing.
11.3.6 Fiber-mat reinforced cement sheets complying with
NOTE 1—The recommended method is to apply the base coat in two
Specification C1325, type A, shall be installed in accordance
applications.
with the sheet producer’s written installation instructions,
12.4.1 The surface shall be free of voids, projections, trowel
which include details of framing type and spacing, fastener
marks and other surface irregularities. The base coat thickness
type and spacing, and sheet orientation and spacing.
shall be not less than ⁄16 in. (1.6 mm) dry as measured from the
11.4 Alignment—All substrate surfaces shall be straight and
surface of the substrate panel.
true within ⁄4 in. in 10 ft. (2 mm/m). More stringent require-
12.5 Reinforcing Mesh Overlap—All reinforcing mesh
ments by the DEFS producer shall supersede the above stated
edges shall be overlapped not less than 2 ⁄2 in. (64 mm).
requirements.
12.6 Impact Layers—When required, higher impact perfor-
11.5 Suitability for Use—The substrate surface shall be firm,
mance shall be achieved with multiple layers of reinforcing
sound, and undamaged in order to receive the exterior finish.
mesh or by incorporating heavier weight reinforcing mesh. All
11.5.1 Broken, cracked or delaminated substrate boards
areas requiring higher impact performance shall be detailed on
shall be replaced or restored to a condition equal to adjacent
the project plans and specifications. When overlapping of high
undamaged boards.
impact mesh is not required, a complete second layer of
11.6 Cleanliness—The surface of all substrates shall be
reinforcing mesh shall be applied over the layer of high impact
clean and free from any foreign materials such as form release
mesh.
agents, curing compounds, dust, dirt, frost, oil or grease,
12.7 Corners—Reinforcing mesh shall not be lapped within
efflorescence and laitance.
8 in. (204 mm) of any corner.
11.6.1 All substrate panels shall have all loose dirt and dust
removed by cleaning methods appropriate for the job and job 12.8 Wall Penetrations—All edges of the substrate panel
conditions.
board at penetrations of the DEFS, such as at windows, doors,
11.6.2 Efflorescence and laitance on substrate panels shall Heating, Ventilation and Air Conditioning (HVAC)
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