ANSI/PHTA/ICC/NPC-12 2025 American National Standard for the Plastering of Swimming Pools and Spas
Approved April 2, 2025
SECRETARIAT:
Pool& Hot Tub Alliance
1650 King St., Ste. 602
Alexandria, VA 22314
703-838-0083
phta.org
Approved April 2, 2025
American National Standards Institute
American National Standard for the Plastering of Swimming Pools and Spas
American National Standard
Approval of an American National Standard requires verification by the American National Standards Institute (ANSI) that the requirements for due process, consensus, and other criteria for approval have been met by the standard developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity.
Consensus requires that all views and objections be considered and that a concerted effort be made toward their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether they have approved this standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards.
The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard.
NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard.
Important Notice about this Document
This voluntary standard has been developed under the published procedures of the American National Standards Institute (ANSI). The ANSI process brings together volunteers representing varied viewpoints and interests to achieve consensus.
The Pool & Hot Tub Alliance (PHTA) does not write the standards. Rather, PHTA facilitates a forum for its members, and others interested in pool and spa design and safety, to develop standards through the consensus procedures of ANSI. While PHTA administers the process and establishes rules to promote fairness in the development of consensus, it does not independently test, evaluate, or verify the accuracy of any information or the soundness of any judgments contained in its codes and standards.
In issuing and making this document available, PHTA is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is PHTA undertaking to perform any duty owed by any person or entity to someone else. PHTA disclaims liability for any personal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication of, use of, or reliance on this document.
PHTA has no power, nor does it undertake, to police or enforce compliance with the contents of this document. PHTA does not list, certify, test, or inspect products, designs, or installations for compliance with this document. Any certification or other statement of compliance with the requirements of this document shall not be attributable to PHTA. Any certification of products stating compliance with requirements of this document is the sole responsibility of the certifier or maker of the statement. PHTA, its members, and those participating in its activities do not accept any liability resulting from compliance or noncompliance with the provisions given herein, for any restrictions imposed on materials, or for the accuracy and completeness of the text.
Anyone using this document should rely on their own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstance. It is assumed and intended that pool and spa users will exercise appropriate personal judgment and responsibility and that public pool and spa owners and operators will create and enforce rules of behavior and warnings appropriate for their facility.
PHTA maintains copyright in all its standards. The ANSI/PHTA/ICC/NPC-12 2025 American National Standard for thePlasteringofSwimmingPoolsandSpas is available for adoption and use by the authority having jurisdiction. Its use within a governmental jurisdiction is intended to be accomplished through adoption by reference in accordance with proceedings established in the jurisdiction's laws. “Adoption by reference” means that in the adopting ordinance, the governing body cites only the title, edition, relevant sections or subsections (where applicable), and publishing information of the standard, and that the actual text of the standard is not included in the ordinance. The adoption should recognize PHTA’s copyright to the Standard. PHTA does not waive copyright in its standards by making its standards available for adoption by reference.
The APSP, The Association of Pool & Spa Professionals®word mark, and the APSP logo are trademarks of The Associationof Pool &Spa Professionals d/b/a Pool & Hot Tub Alliance registered in the U.S.
The Pool & Hot Tub Alliance® word mark and logo are registered trademarks of TheAssociation of Pool & Spa Professionals d/b/a Pool & Hot Tub Alliance registered in the U.S.
ICC Copyright Notice
Trademarks: The “International Code Council,” “International Swimming Pooland Spa Code,” the acronyms “ICC” and “ISPSC,” and the ICC logogram are registered trademarks and service marks of ICC.Use of these marks is not authorized without the express permission of ICC.
This Foreword is not part of the American National Standard ANSI/PHTA/ICC/NPC-12 2025. It is included for information only.
The ANSI/ PHTA /ICC/NPC - 12 20 2 5 , AmericanNationalStandardforthePlasteringof SwimmingPoolsandSpas, was approved by ANSI on April 2, 2025.
This standard ANSI/PHTA/ICC/NPIC-12 2025 is a revision.
Revision History:
Designation
ANSI/APSP/ICC/NPC-12
2016a
ANSI/APSP/ICC/NPC-12
2016
American National Standard for the Plastering of Swimming Pools and Spas, Supplement A
American National Standard for the Plastering of Swimming Pools and Spas
Supplement May 10, 2019
Original November 3, 2015
Federal, state, local, and international authorities, as well as industry members and consumers, recognize the need for modern, up-to-date standards governing the design, construction, alteration, repair, and maintenance of swimming pools, spas, hot tubs, and aquatic facilities and other water-containment vessels
This standard was designed to accomplish this need by addressing the cementitious interior finish of swimming pools, spas, and other aquatic facilities, public and residential. It is also intended to assist state local jurisdictions, and well as national and international regulatory bodies, where necessary, in the development and promulgation of criteria for this purpose. It is also intended for adoption into the International Swimming Pool and Spa Code™ (ISPSC) published jointly with the International Code Council (ICC) and the Pool and Hot Tub Alliance (PHTA).
The design recommendations and construction practices in this standard are based upon sound engineering principles, research, and field experience that, when applied properly, contribute to the delivery and installation of a reliable and safe product. The recommendations in this standard are not designed or intended to reference or preclude all potential or alternative materials or methodologies. The primary focus of this document is to substantiate sound common practices currently utilized throughout the U.S. Plastering Trade that have shown a satisfactory history of performance. Specifications in this standard should not limit the Trade from using materials, methods, or practices that have been shown historically to achieve an equivalent performance. Preferred nuances, regional variations, and increased levels of quality or performance can be specified or stipulated by contract that meet or exceed the minimum provisions herein.
The words “safe” and “safety” are not absolutes. While the goal of this standard is to design and construct a safe, enjoyable product, it is recognized that risk factors cannot, as a practical matter, be reduced to zero in any human activity. This standard does not replace the need for good judgment and personal responsibility. In permitting use of the
pool, spa, or swim spa by others, owners must consider the skill, attitude, training, and experience of the expected user.
As with any product, the specific recommendations for installation and use provided by the manufacturer should be carefully observed.
This standard was prepared by the PHTA-12 Standard Writing Committee of the Pool & Hot Tub Alliance (PHTA) and the National Plasters Council (NPC) in accordance with American National Standards Institute (ANSI)’s ANSI Essential Requirements: Due processrequirementsforAmericanNationalStandards.
Suggestions for improvement of this standard should be sent to the Pool & Hot Tub Alliance (formerly the Association of Pool and Spa Professionals), 1650 King Street, Ste. 602, Alexandria, VA 22314.
Development
The first ANSI-accredited version of the ANSI/APSP/ICC/NPC - 12 2016 Standardforthe Plastering of Swimming Pools and Spas was the culmination of a review and drafting effort of Jonathan E. Dongell of the National Plasterers Council, including the following:
- The National Plasterers Council Technical Manual adopted by the National Plasterers Council in 2005;
- The National Plasterers Council’s Commercial Specification for Swimming Pool Plastering, adopted by the National Plasterers Council in 2014;
- Relevant sections of current codes, specification, standards, and manuals from the International Code Council (ICC), ASTM International, and American Concrete Institute (ACI).
This standard is published in partnership with the International Code Council (ICC), the leading global source of model codes and standards and building safety solutions that include product evaluation, accreditation, technology, codification, training, and certification. ICC develops and publishes the International Codes, which are adopted as the basis for the building codes used in most states and jurisdictions within the United States as well as many countries around the globe. Additionally, PHTA and ICC have collaborated to develop the first comprehensive model swimming pool and spa code, known as the International Swimming Pool and Spa Code (ISPSC). This landmark document incorporates and references material from ANSI/PHTA standards and ICC model codes, to create a stand-alone code that is consistent with codes and standards from both organizations.
The ISPSC and this standard are the result of joint efforts between ICC and PHTA as a service to both the swimming pool and spa community and building code professionals. It is the hope of both organizations that they will lead to enhanced safety for pool and spa users around the world.
Organizations Represented
Consensus approval in accordance with ANSI procedures was achieved by ballot of the following PHTA Standards Consensus Committee (SCC) and through an ANSI Public Review process. The ANSI Public Review provided an opportunity for additional input from industry, academia, regulatory agencies, safety experts, state code and health officials, and the public at large. Inclusion in this list does not necessarily imply that the organization concurred with the submittal of the proposed standard to ANSI. The voting membership of the SCC is comprised of four interest categories: Producer, User-Government, UserConsumer, and General Interest.
PHTA Standards Consensus Committee (SCC)
Producer
American Pools & Spas. Bruce Carney (Vice Chair) Fluidra Philip Escobedo
Hayward Industries, Inc. John O’Hare, CSP, CBP
Idaho Aquatic Services, LLC/Idaho Pool Remodeling. Scott Heusser, CPO, CPOI, CPI, CAEA
Latham Pool Products, Inc.. Michael Tinkler Team Horner Group Inc.. Lars R. Hagen
User - Government
Cecil County Government William V. Funk, Jr. City of Martinsville, VA - Community Development Kris Bridges, MCP, CBO, CZA
CSG Consultants Mike Teemant
Johnson County Department of Health and Environment Kevin Baugh
Thomas Vyles, REHS/RS
Public Health Seattle & King County. Jun Naotsuka Town of Flower Mound
Utah Department of Health and Human Services Sarah Cheshire
User - Consumer
Abbey’s Hope Charitable Foundation. Alan Korn American National Red Cross. Stephanie Shook NC Pool School Terri Stroupe Tropic Falls at OWA. John Broughton The ZAC Foundation Megan Ferraro
General Interest
IAPMO. Sung Choe International Code Council. Lisa Reiheld
RJR Engineering Co., Inc.. James Rumen, P.E. World Waterpark Association. Rick Root
U.S. Consumer Product Safety Commission (CPSC). Rebekah Kempske
PHTA
- 12 Standard Writing Committee
(SWC)
Voting Members
Aquatic Technology Pool & Spa. Paolo Benedetti
Burketts Pool Plastering and Remodeling ................................................................................................ Shaun Goldberg
American National Standard for the Plastering of Swimming Pools and Spas
Part 1 – General
1.1.
Scop e
1.1.1. This standard covers the material and application for the plastering of cementitious finish coatings for in-ground swimming pools or other cementitious water-containment vessels.
1.1.2. Except to the extent specified in the Standard, the terms specified by contractual agreement shall govern.
1.1.3. Except where indicated, this Standard shall apply to the public and residential plastering of swimming pools.
1.1.4. Where designated “For Public Swimming Pools Only”, this portion of the Standard shall apply to Class A, B, D, E, and F public swimming pools as defined in ANSI 1/APSP 2/ICC-1 [1], and shall not apply to residential or Class C public swimming pools.
1.2. Definitions and Acronyms
Definitions:
Plastering. The methodology and/or action of applying a cementitious interior finish coating material in a swimming pool or other water-containment vessel.
Related Work. Work stipulated by contract that is outside the scope of plastering, which becomes required work when accepted by Plastering Company by contract. Work. The labor, materials, services, scaffolding, equipment, and procedures required to perform the plastering of the interior of a swimming pool, spa, water feature, or other water-containment vessel.
1 American National Standards Institute (ANSI), 25 West 43rd Street, New York NY 10036 USA, 1-212-642-4900, www.ANSI.org
2 The Pool and Hot Tub Alliance (PHTA) (formerly the Association of Pool and Spa Professionals (APSP)), 1650 King Street, Ste. 602, Alexandria, VA 22314 USA, 1-703-838-0083, www.phta.org
Acronyms:
Acronym Term
AIA American Institute of Architects
ACI American Concrete Institute
AHJ Authority Having Jurisdiction
ANS American National Standard
ANSI American National Standards Institute
APSP Association of Pool and Spa Professionals (now PHTA)
IBC International Building Code
ICC International Code Council
ISPSC International Swimming Pool and Spa Code
PCA Portland Cement Association
PHTA Pool and Hot Tub Alliance (formerly APSP)
NPC National Plasterers Council
1.3. Summary
1.3.1. ‘Work’ shall include all labor, materials, services, scaffolding, and equipment required to perform the plastering of the interior of a swimming pool, spa, water feature, or other water-containment vessel, and related work as per the project stipulations, in accordance with drawings, plans, and provisions of the contract.
1.3.2. ‘Swimming pool,’ ‘water feature,' and ‘water-containment vessel’ are used within this standard interchangeably, and shall include any permanent vessel having a cementitious substrate designed to hold water, and that will have a cementitious interior finish coating applied (plastered) that will remain submersed in water during service life.
1.3.3. For the purposes of this standard, ‘plastering’ shall designate the methodology and/or action of applying a cementitious interior finish coating material in a swimming pool or other water-containment vessel.
1.4. Applicable Governing Documents
1.4.1. All drawings, plans, and general provisions of the contract shall govern.
1.4.2. All codes, specifications, standards, manuals, guides, and related documents from Section 1.5 that are applicable to the trade practice of plastering of cementitious interior finish coatings for cementitious water containment vessels, and related work, when stipulated within the drawings, plans, or provisions of the contract, shall govern.
1.5. Applicable Most Recent Edition Codes, Specifications, Standards, Manuals, and Guides Related to Plastering, Concrete, and Swimming Pools
1.5.1. PHTA Standards:
[1] ANSI/APSP/ICC-1 2014 (R2023) American National Standard forPublicSwimmingPools
[2] ANSI/PHTA/ICC-7 2020 American National Standard for SuctionEntrapmentAvoidanceInSwimmingPools,Wading Pools,Spas,HotTubsandCatchBasins
[3] ANSI/APSP/ICC-16 2017 American National Standard for Suction Outlet Fitting Assemblies (SOFA) for Use in Pools, SpasandHotTubs
1.5.2. Related Sections in the ICC International Building Code (IBC) Code 3:
[4] Chapter 19 – Concrete
[5] Section 1910 – Shotcrete
[6] Section 2511 – Interior Plaster
[7] Section 2512 – Exterior Plaster
[8] Section 2512 – Exposed Aggregate Plaster
1.5.3. Related Sections in the ICC International Swimming Pool and Spa Code (ISPSC) 4:
[9] Section 307.3 – Materials
[10] Section 307.4 – Structural Design
[11] Section 307.6 – Surface Condition
[12] Section 307.7 – Colors and Finish
[13] Section 411.5 – Underwater Seats, Benches, and Swimouts
[14] Table 502.1 – Reservoirs and Shells
[15] Section 610.5 – Pool Steps
3 The International Code Council (ICC), 200 Massachusetts Ave, NW, Suite 250, Washington, DC 20001 USA, 1-888ICC-SAFE (422-7233), www.iccsafe.org
4 The International Code Council (ICC), 200 Massachusetts Ave, NW, Suite 250, Washington, DC 20001 USA, 1-888ICC-SAFE (422-7233), www.iccsafe.org
[16] Section 610.6 – Swimouts
[17] Section 610.7 – Underwater Seats and Benches
[18] Section 802.1 – Materials of Components and Accessories
[19] Section 802.3 – Structural Design
1.5.4. Related ASTM 5 Specifications:
[20] C 109 Standard Test Method for Compressive Strength of Hydraulic Cement Mortars
[21] C 150 Standard Specification for Portland Cement
[22] C 311 Standard Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use in Portland-Cement Concrete
[23] C 494 Specifications for Chemical Admixtures for Concrete
[24] C 595 Specification for Blended Hydraulic Cements
[25] C 897 Standard Specification for Aggregate for Job-Mixed Portland Cement-Based Plasters
[26] C 926 Standard Specification for Application of Portland Cement-Based Plaster
[27] C 932 Standard Specification for Surface-Applied Bonding Compounds for Exterior Plastering
[28] C 979 Standard Specification for Pigments for Integrally Colored Concrete
[29] C 1059 Standard Specification for Latex Agents for Bonding Fresh to Hardened Concrete
[30] C 1157 Standard Performance Specification for Hydraulic Cement
[31] C 1778 Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete
[32] D 4258 Standard Practice for Surface Cleaning Concrete for Coating
[33] D 4259 Standard Practice for Abrading Concrete
5 ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959 USA, 1-610-8329500, www.ASTM.org
[34] D 4261 Standard Practice for Surface Cleaning Concrete Unit Masonry for Coating
[35] D 4262 Standard Test Method for pH of Chemically Cleaned or Etched Concrete Surfaces
[36] D 5295 Standard Guide for Preparation of Concrete Surfaces for Adhered (Bonded) Membrane Waterproofing Systems
[37] E 1857 Standard Guide for Selection of Cleaning Techniques for Masonry, Concrete, and Stucco Surfaces
1.5.5. Related ACI 6 Code and Guide Documents:
[38] 318 Building Code Requirements for Structural Concrete
[39] 350 Building Code Requirements for Environmental Engineering Concrete Structures
[40] 201.2R Guide to Durable Concrete
[41] 225.R Guide to the Selection and Use of Hydraulic Cements
[42] 306.R Guide to Cold Weather Concreting
[43] 308.R Guide to Curing Concrete
[44] 506.R Guide to Shotcrete
[45] 515.R Guide to Barrier Systems
[46] 524.R Guide to Portland Cement-Based Plaster
[47] 546.R Concrete Repair Guide
1.5.6. Related Sections in AIA 7 MasterSpec:
[48] Division 1 – General and Supplementary Conditions
1.6.1. Access to the jobsite and to the swimming pool shall be uninterrupted for the duration of the work.
1.6.2. Access to the storage of equipment and materials shall be uninterrupted for the duration of the work.
1.6.3. Access to utilities, potable water, and drainage shall be uninterrupted for the duration of the work.
1.7. Delivery, Storage, and Handling
1.7.1. Delivery, storage, and handling of materials shall be in accordance with the manufacturer’s recommendations.
1.8. Project Placement Conditions
1.8.1. Solid base substrate to receive plaster coating shall comply with ASTM C 926 [26] Section 5, and Annexes A1 – Mandatory General Information Sections A1.6; A.1.6.3; and A.2.1.5, as well as Sections 3.2.1.2 and 3.5 herein.
1.8.2. All materials applied to the solid base substrate and/or plaster coating, whether waterproofing, bond coat, leveling coat, or alternative finish coating materials, shall be compatible for usage in a swimming pool environment, and shall comply with the manufacturer’s instructions with regard to use, surface preparation, and application conditions.
1.8.3. The daily average temperature of the ambient air, from midnight to midnight, shall be greater than 40°F (4.4°C) and the temperature of the substrate shall be above 32°F (0.0°C) during the plastering application.
8 National Plasterers Council (NPC), 1000 N. Rand Road, Suite 214, Wauconda, IL 60084 USA, 1-847-416-7272, www.npconline.org
9 Portland Cement Association (PCA), 200 Massachusetts Ave NW, Suite 200, Washington, DC 20001 USA, 1-202-4089494, www.cement.org
1.8.4. No people, animals, debris, paint, or other contaminants shall be allowed to enter the swimming pool after plastering or during the water fill.
1.8.5. Post-installation, any non-submersed areas of the finish coating shall be protected from freezing temperatures for a minimum of 48 hours after final set.
1.8.6. Except as indicated in 1.8.7, the swimming pool or water vessel shall immediately be filled with potable water or source water approved by the Authority Having Jurisdiction (AHJ) upon final set. The water shall not be stopped until the finish coating is completely submersed.
1.8.7. Alternative, proprietary, or high-performance finishes shall be treated in accordance with the manufacturer’s surface exposure procedures and fill instructions
1.8.8. When stipulated as related work, the plasterer shall make available written startup instructions for the party to start up the pool.
2.1. ‘ Non - Applicable’ (Prohibited) Materials of Swimming Pool Interior Finishes
2.1.1. Structural reinforcement steel shall not be allowed.
2.1.2. Metal lath shall not be allowed.
2.1.3. Wire shall not be allowed.
2.1.4. No metals, other than those listed in Section 2.2.2, shall be permitted to be attached to, or be within, a swimming pool interior finish coating material. Metal reinforcement within the solid-base substrate shall be embedded to a depth of at least 2 in. (5 cm ) below the solid substrate surface that will be receiving the interior plaster finish coating as per ACI 350 [39] Section 7.7.1.
2.1.5. Corroded metal reinforcement within the solid-base substrate shall be removed and sealed to a depth of at least 2 in. (5 cm ) below the solid substrate surface receiving the interior finish coating.
2.1.6. Lime shall not be allowed (see Section 2.3.5).
2.2. Miscellaneous Materials
2.2.1. Fibers shall be alkaline-resistant glass fibers, polypropylene, or cellulosic. Fibers shall be free of contaminants that cause damage to the finish coating or any component of the finish coating. Fibers shall be manufactured and acceptable for use with hydraulic cement-based materials and shall be used in accordance with the manufacturer’s instructions
2.2.2. Any metal accessories to be in contact with the cement-based finish coating shall be non-reactive to the cement, pool chemicals, and the water conditions found in swimming pools and spas, or as approved by the AHJ
2.2.3. Tile, Joint Materials, Curable Materials – For Public Swimming Pools Only
Joint materials that separate or divide the finish coating shall be pre-set level to the anticipated height of the hardened finish coating.
2.2.3.1. Perimeter tiles, step trim tiles, and tile or material used as joints, breaks, or stops, must be pre-set level to the anticipated height of the hardened finish coating.
2.2.3.2. Tile for steps, benches, and swimouts shall be in accordance with Section 3.3.3.
2.2.3.3. Curable materials (e.g., thinset, bond coat, waterproofer, sealants, sealers, water plug, joint compounds, or similar curable material) shall
be cured in accordance with the manufacturer’s instructions prior to the application of the interior finish, and shall be compatible with the cement, pool chemicals, and the water conditions
2.2.3.4. Flexible or movement joint materials that will divide the finish coating shall have a rigid material installed on both sides of the flexible joint. The rigid material that borders the joint material shall be pre-set to the anticipated level of the hardened finish coating. Flexible and/or movement joint materials shall be installed in accordance with the manufacturer's instructions.
2.3. Plaster Materials
2.3.1. Water for mixing shall be potable water and free of substances capable of affecting set time, as per ASTM C 926 [26] Section 4.5.
2.3.2. Hydraulic cement shall comply with one of the following specifications:
2.3.2.1. White Portland Cement: ASTM C 150 [21], Type I
2.3.2.2. White Blended Cement: ASTM C 595 [24], Type IP.
2.3.2.3. White Blended Cement: ASTM C 595 [24], Type IL (limestone).
2.3.2.4. White Cement: ASTM C 1157 [30], Type GU.
2.3.3. Sand/aggregate shall comply with ASTM C 897 [25], ASTM C 1778 [31], and ASTM C 926 [26], or shall fall within one or more of the following specialty categories:
2.3.3.1. White marble, limestone, or dolomite sand.
2.3.3.2. Light-toned silica sand.
2.3.3.3. Narrow gradation sand or aggregate for exposed surfaces.
2.3.3.4. Color-coated or “accent” particles of sand or aggregate.
2.3.3.5. Formulated or colored, natural or synthetic, sand or aggregate, chosen to match or contrast the pigmented cementitious material background color.
2.3.3.6. Pre-blend, pre-mix, or proprietary mixes of sand/aggregate/accent material.
2.3.4. Pigment/colorant for job-mixed finish coatings shall comply with ASTM C 979 [28], and be compatible with other components of the mix design, and be used in accordance with the manufacturer’s instructions.
2.3.4.1. Organic and/or inorganic pigment shall produce the approved color match to architect’s, builder’s, and/or owner's chosen sample or
mockup.
2.3.5. Lime shall not be used in the mix design of swimming pool interior finish coatings. This does not prohibit the usage of marble, limestone, or dolomite to be used as a filler, fines, sand, or aggregate component of a mix design.
2.4. Plaster Mix Designs
2.4.1. Mix design shall comply with ASTM C 926 [26] Section 6 for general mix design requirements of plaster.
2.4.2. Mix design shall comply with the National Plasterers Council Technical Manual [53] for mix proportions specific to swimming pools, spas, and water features for base coat (scratch coat) and top coat (double) as follows:
2.4.2.1. General usage mix proportions shall be 1 part hydraulic cement and 1.5 – 2 parts sand/aggregate, by weight.
2.4.2.2. Exposed sand/aggregate mix proportions shall be 1 part hydraulic cement and 1 – 1.5 parts sand/aggregate, by weight.
2.4.2.3. Additives for set control shall allow sufficient time to properly apply and finish the material and to properly harden. Additives for set control shall be used in accordance with the manufacturer's instructions.
2.4.2.4. Pozzolanic and/or polymeric additives for workability and/or durability shall not adversely affect the ability of the technician to properly finish the material. Pozzolanic and/or polymeric additives shall be used in accordance with the manufacturer's instructions.
2.4.2.5. Where used, pre-blend, pre-mix, or approved proprietary finish coating products shall be used in accordance with the manufacturer’s instructions for proper mixing, application, and finishing.
Part 3 – Execution
3.1. General
3.1.1. Prior to plastering, dirt, debris, grease, oil, or other contaminants, or standing water shall be removed from the swimming pool substrate.
3.1.2. The substrate structure shall be structurally sound, and all loose or damaged sections be repaired or corrected by the responsible party prior to plastering.
3.1.3. Adjacent work, and pertinent areas or materials around work, shall be protected from soiling, spattering, staining, or damage, prior to beginning plastering installation.
3.2. P re - Site, Examination, and Preparation – For Public Swimming Pools Only
3.2.1. When stipulated, a pre-site meeting for architect, builder, owner, and/or installer to examine the jobsite and the water-containment vessel substrate shall include the following:
3.2.1.1. Acceptability of the solid-base substrate and verification that compliance to all contract plastering requirements are achievable, given the current condition of the substrate.
3.2.1.2. The plastering application shall comply with the stipulations for adverse weather conditions, as per Section 1.8.3
3.2.1.3. Concerns, observations, and resolutions to issues that will otherwise negatively affect the installer’s capability to perform work adequately shall be reported in writing to satisfy the requirements of Section 3.2.1.1
3.2.1.4. Considerations of, or alterations to, the contract work shall be in writing, including materials, application, and/or installation of materials based on prevailing substrate condition, placement conditions, and/or the environment, to satisfy the requirements of Section 3.2.1.3.
3.2.1.5. Access to the jobsite, swimming pool, utilities, potable water, drainage, and storage of equipment and material shall be in accordance with Section 1.6.
3.2.1.6. Potable water supply with adequate water pressure to facilitate mixing of materials and subsequent filling of the swimming pool or watercontainment vessel.
3.2.2. Unsatisfactory conditions found during pre-site meetings or examinations
of the swimming pool substrate made by the installer, as per Section 3.2.1, shall be reported to the architect, builder, owner, or AHJ, and be corrected by the responsible party prior to plastering.
3.2.3. Observations and corrections, as per Section 3.2.2, shall conform to ASTM C 926 [26] Section 5 – regarding applicable requirements for solid-base substrate preparation, including applicable parts of ASTM C 926 [26] Annexes – Mandatory Information.
3.3. Installing Accessories
3.3.1. Prior to the swimming pool being placed into service, the proper drains and suction covers shall be present, installed, and affixed in accordance with applicable safety standards as set forth by ANSI/PHTA/ICC-7 [2] and ANSI/APSP/ICC-16 [3]
3.3.2. Lights, handrails, circulation return heads or directionals, and other accessories shall be installed and properly secured.
3.3.3. For public pools only, tile for steps, benches, and swimouts shall be of a contrasting color and installed as set forth by ISPSC Section 411.5 [13], Section 610.5.3 [15], Section 610.6.4 [16], and Section 610.7.5 [17] Note: This includes Class C.
3.4. Pre - Coatings and Plastering Application
3.4.1. All pre-coatings or proprietary materials, whether waterproofing, bond coat, leveling coat, or alternative cementitious interior finish coating materials, shall be installed in accordance with the manufacturer's instructions.
3.4.2. The plastering application shall conform to the applicable sections of ASTM C 926 [26] Section 7.3 through Section 8.2.
3.4.3. Public and commercial interior finishes shall be installed and finished in accordance with the approved sample or mockup and in accordance with the AHJ.
3.4.4. The coloration of commercial pool interior finishes shall be installed in accordance with ISPSC-stipulated minimum lightness levels, or as stipulated by the AHJ.
3.4.5. The finished surface of the finish coating shall be beveled smooth to transitions and tight against all abutting materials.
3.4.6. The interior finish shall be applied in a manner that averages between 3/8 in. and 3/4 in. (1-2 cm ) thickness.
3.5. Patching of Finish
3.5.1. When stipulated, patching or other repairs of the finish coating shall comply as follows:
3.5.1.1. Minor holes and/or cracks shall be repaired with appropriate materials such as with like, sanded or un-sanded, materials as is necessary to facilitate such repair.
3.5.1.2. Minor imperfections or rough areas of the surface shall be polished, sanded, chemically treated, or otherwise repaired to within standard trade practices.
3.6. Cleaning Jobsite and Protection of Finish
3.6.1. When necessary, temporary protection shall be put into place to protect the finish coating.
3.6.2. Temporary protection material(s) and all other debris created from the plastering application shall be removed and disposed of properly.
3.6.3. Overspray, splashes, or residue from work material(s) shall be promptly removed from adjacent tile work, decking, or other surfaces.
3.6.4. All tile, decking, and surrounding surfaces that become stained, marred, or otherwise damaged during the plastering application shall be cleaned and/or repaired.
3.6.5. Upon completion, fill the swimming pool as per Section 1.8.6
ANSI/PHTA/ICC/NPC-12 2025
American National Standard for Plastering of Swimming Pools and Spas
This standard addresses the cementitious interior finish of swimming pools, spas, and other aquatic facilities, public and residential. Familiarity with all of PHTA’s ANSI-approved American National Standards is essential for anyone who builds, manufactures, sells, or services pools, spas, or hot tubs.
