ASTM D7120/D7120M-10(2022)

Standard Guide for Evaluation and Preparation of Roof Membranes for Coating Application

SIGNIFICANCE AND USE
3.1 This guide outlines the general procedures necessary to evaluate and prepare a roof membrane for the application of a liquid surface coating.  
3.2 This guide is not all inclusive; this guide is intended to supplement detailed instructions from manufacturers and safety requirements required by law.
SCOPE
1.1 This guide covers the procedures for evaluating and preparing non-aggregate surfaced membranes for the application of a coating. It does not address design, construction, or installation issues regarding the roof assembly or the roof membrane. It is not an application guide for roof coatings.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.  
1.3 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

• Status: Published
• Publication Date: 31-Oct-2022
• ICS: 25.220.10 - Surface preparation
• Technical Committee: D08 - Roofing and Waterproofing
• Drafting Committee: D08.20 - Roofing Membrane Systems

Overview

ASTM D7120/D7120M-10(2022), titled Standard Guide for Evaluation and Preparation of Roof Membranes for Coating Application, provides a comprehensive framework for ensuring non-aggregate surfaced roof membranes are properly evaluated and prepared prior to receiving a coating. Developed by ASTM International, this standard sets out procedures to improve coating adhesion and roof membrane performance, but is not intended as a guide for the coating application itself or for design, construction, or installation of roof assemblies.

Proper evaluation and preparation are critical for restoring roof durability, extending service life, and enhancing the performance of liquid-applied roof coatings. This guide supplements manufacturer instructions and does not replace mandatory health, safety, and environmental requirements under law.

Key Topics

• Evaluation of Roof Membrane Surface
  The guide details general procedures for assessing roof membrane surfaces, including the identification and removal of contaminants, ensuring the surface is clean and dry, and performing specific evaluations such as:

  • White cloth evaluation (for smooth membranes)
  • Cloth tape evaluation (for mineral-surfaced membranes)

• Surface Contaminants
  Common contaminants that impair coating adhesion are identified:

  • Air- or water-borne dust, dirt, and debris
  • Oils, greases, and chemicals from industrial operations
  • Biological barriers such as algae or fungus
  • Exudates and release agents from manufacturing

• Surface Preparation Techniques
  Appropriate techniques are outlined to ensure optimal surface conditions:

  • Manual brooming to remove debris
  • Scrubbing with a stiff-bristled brush and water
  • Power washing with proper attention to membrane integrity
  • Pressure washing for loose particulate removal

• Continuous Evaluation
  Emphasizes the need to assess roof conditions not only before but also during the coating process to avoid application to contaminated surfaces.

• Environmental and Safety Considerations
  Users must identify and follow all relevant safety, health, and regulatory requirements for their jurisdiction, and consult manufacturer recommendations for surface priming and temperature conditions.

Applications

The ASTM D7120/D7120M standard is widely used in the roofing and waterproofing industry for:

• Extending service life: Proper surface preparation improves coating adherence, enabling roof membrane coatings to perform as intended and increasing overall roof durability.
• Roof restoration projects: Facility managers, roofing contractors, and maintenance professionals use these guidelines to prepare aged or weathered membranes before applying restoration coatings.
• Quality assurance: Ensures that any roof coating investment is founded on a robust, consistent process for membrane cleaning and preparation.
• Reducing risk of coating failure: By following these evaluation and preparation steps, users minimize costly failures due to poor adhesion, surface contamination, or overlooked moisture.

Related Standards

For professionals involved in roof coating projects and maintenance, the following related standards are also highly relevant:

• ASTM D6083: Standard Specification for Liquid Applied Acrylic Coating Used in Roofing
• ASTM D3468: Standard Specification for Liquid-Applied Neoprene and Chlorosulfonated Polyethylene Used in Roofing and Waterproofing
• ASTM D7051: Guide for Determination of Roof System Compatibility
• ASTM D1623: Standard Test Method for Tensile and Adhesion Properties of Roof Coatings

Proper application of these standards, in conjunction with ASTM D7120/D7120M, ensures roof coating projects meet industry best practices for evaluation, preparation, and durability.

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Keywords: roof membrane preparation, roof coating application, surface evaluation, roof contaminants, ASTM D7120, roof restoration, coating adhesion, roofing 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: D7120/D7120M − 10 (Reapproved 2022)
Standard Guide for
Evaluation and Preparation of Roof Membranes for Coating
Application
This standard is issued under the fixed designation D7120/D7120M; 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 top surface of a roof. Surface contaminants come from one of
thefollowingsources:(1)particulateandliquidemissionsfrom
1.1 This guide covers the procedures for evaluating and
building interior operations, (2) airborne vegetable and mineral
preparing non-aggregate surfaced membranes for the applica-
particles, and (3) oils, greases, and chemicals from industrial
tion of a coating. It does not address design, construction, or
and food service operations.
installation issues regarding the roof assembly or the roof
membrane. It is not an application guide for roof coatings.
2.2.2 chemical barrier, n—a barrier formed by reactive
materials either acid, alkali, or solvent, which inhibits the
1.2 The values stated in either SI units or inch-pound units
adhesion of surface coatings.
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
2.2.3 exudate, n—a glossy film that forms on the surface of
system shall be used independently of the other. Combining
an atactic polypropylene (APP) membrane. Exudates inhibit
values from the two systems may result in nonconformance
coating adhesion and they can bleed through and stain the
with the standard.
coating surface.
1.3 This standard does not purport to address all of the
2.2.4 loose mineral granules, n—see mineral granules,
safety concerns, if any, associated with its use. It is the
disattached mineral granules.
responsibility of the user of this standard to establish appro-
2.2.5 moisture, n—surfaces to be coated must be clean and
priate safety, health, and environmental practices and deter-
dry.
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor-
2.2.6 organic barrier, n—see organic, any of several bio-
dance with internationally recognized principles on standard-
logical growths, usually algae or fungus, which act as a barrier
ization established in the Decision on Principles for the
between an APP roof membrane and a coating.
Development of International Standards, Guides and Recom-
2.2.7 release and/or anti-block agent, n—see parting agent,
mendations issued by the World Trade Organization Technical
any of several mineral or waxy materials which are typically
Barriers to Trade (TBT) Committee.
applied to an APP sheet during the manufacturing process to
2. Terminology
prevent the sheet from sticking to itself while in the roll.
2.1 Definitions:
2.2.8 surface oxidate, n—a barrier film, which forms on the
2.1.1 adequate drainage, n—the drainage condition in
surfaceofanunprotectedsmoothAPPsheetduringweathering.
which consideration has been made for all loading deflections
of the deck, and additional roof slope has been provided to
3. Significance and Use
ensure drainage of the roof area within 48 h of rainfall.
3.1 This guide outlines the general procedures necessary to
2.1.2 contaminant, n—any substance which will adversely
evaluate and prepare a roof membrane for the application of a
affect the adhesion of a coating.
liquid surface coating.
2.2 Contaminant List:
3.2 This guide is not all inclusive; this guide is intended to
2.2.1 air/water-borne surface contaminant, n—any of sev-
supplement detailed instructions from manufacturers and
eral types of external source contaminants that accumulate on
safety requirements required by law.
This guide is under the jurisdiction of ASTM Committee D08 on Roofing and
4. General Surface Conditions
Waterproofing and is the direct responsibility of Subcommittee D08.20 on Roofing
Membrane Systems.
4.1 Lackofadequatedrainagewillhaveanadverseeffecton
Current edition approved Nov. 1, 2022. Published November 2022. Originally
roof components and will lead to premature failure of liquid-
approved in 2010. Last previous edition approved in 2017 as D7120/D7120M – 10
(2017). DOI: 10.1520/D7120_D7120M-10R22. applied coatings.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7120/D7120M − 10 (2022)
4.2 It is important to determine the area(s) affected by usually a high concentration of dust, dirt, and debris in areas
adverse surface conditions. Specific surface preparation op- where water has ponded.
tions can be determined after the membrane has been evaluated
6. Preparation of the Surface
and subsequent adhesion tests performed.
6.1 Remove contaminants prior to coating. The following
4.3 Multiplesurfacepreparationtechniquesmayberequired
treatments offer different methods of preparing the membrane
to prepare the surface of an APP modified bitumen to receive
surfaces to receive the coating. The roof must be inspected
a coating.
prior to performing any of the following surface preparations.
5. Roof Surface Evaluation If not properly executed, some of these treatments can damage
the membrane.
5.1 The roof membrane surf
...