Painting & Coating Industry (PCI) logo Powder coating summit logo
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • PRODUCTS
  • MATERIALS
  • TECHNOLOGIES
  • RESOURCES
  • EVENTS
  • DIRECTORIES
  • EMAGAZINE
  • CONTACT
  • SIGN UP!
cart
facebook twitter linkedin youtube
  • NEWS
  • Latest News
  • Market Trends & Reports
  • Price Alerts
  • Subscribe to eNewsletters
  • Global Top 10/ PCI 25
  • Weekly Featured Article
  • COATLE Word Game
  • PRODUCTS
  • Product News
  • Must See Products and Services
  • MATERIALS
  • Additives
  • Resins/Polymers
  • Pigments
  • Equipment
  • Distributors
  • TECHNOLOGIES
  • Adhesives
  • Architectural Coatings
  • FINISHING
  • Industrial Coatings
  • Nanotechnology
  • Powder Coatings
  • Solventborne
  • Special Purpose Coatings
  • Sustainability
  • UV Coatings
  • Waterborne
  • FINISHING
  • Finishing News
  • Finishing Technologies
  • Finishing Equipment
  • Finishing Today
  • RESOURCES
  • Columns
  • Blogs
  • Coatings Supplier Handbook
  • Podcasts and Videos
  • PCI Store
  • Classifieds
  • eBooks
  • Sponsor Insights
  • White Papers
  • COATLE Word Game
  • Columns
  • Ask Joe Powder
  • Did you know?
  • Distribution Dive
  • Focus on Canada
  • Formulating With Mike
  • Innovation Insights
  • Moody's Coatings Conundrums
  • Powder Coating Perspectives
  • Target the Market
  • TiO2 Insider
  • Blogs
  • Editor's Viewpoint
  • Industry Insights
  • Podcasts and Videos
  • COAT-IT! Podcast
  • Videos/PCI TV
  • EVENTS
  • Coatings Trends & Technologies Summit
  • Paint and Coatings Academy
  • Webinars
  • Calendar of Events
  • Lifetime Achievement Award
  • DIRECTORIES
  • Buyer's Guide
  • Equipment Directory
  • Materials Directory
  • EMAGAZINE
  • Current Issue
  • eMagazine Archive
  • China Issue Archive
  • Editorial Advisory Board
  • CONTACT
  • Contact Us
  • Advertise
  • Subscribe to eMagazine
  • Subscribe to eNewsletters
Painting & Coating Industry (PCI) logo Powder coating summit logo
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Painting & Coating Industry (PCI) logo Powder coating summit logo
  • NEWS
    • Latest News
    • Market Trends & Reports
    • Price Alerts
    • Subscribe to eNewsletters
    • Global Top 10/ PCI 25
    • Weekly Featured Article
    • COATLE Word Game
  • PRODUCTS
    • Product News
    • Must See Products and Services
  • MATERIALS
    • Additives
    • Resins/Polymers
    • Pigments
    • Equipment
    • Distributors
  • TECHNOLOGIES
    • Adhesives
    • Architectural Coatings
    • FINISHING
      • Finishing News
      • Finishing Technologies
      • Finishing Equipment
      • Finishing Today
    • Industrial Coatings
    • Nanotechnology
    • Powder Coatings
    • Solventborne
    • Special Purpose Coatings
    • Sustainability
    • UV Coatings
    • Waterborne
  • RESOURCES
    • Columns
      • Ask Joe Powder
      • Did you know?
      • Distribution Dive
      • Focus on Canada
      • Formulating With Mike
      • Innovation Insights
      • Moody's Coatings Conundrums
      • Powder Coating Perspectives
      • Target the Market
      • TiO2 Insider
    • Blogs
      • Editor's Viewpoint
      • Industry Insights
    • Coatings Supplier Handbook
    • Podcasts and Videos
      • COAT-IT! Podcast
      • Videos/PCI TV
    • PCI Store
    • Classifieds
    • eBooks
    • Sponsor Insights
    • White Papers
    • COATLE Word Game
  • EVENTS
    • Coatings Trends & Technologies Summit
    • Paint and Coatings Academy
    • Webinars
    • Calendar of Events
    • Lifetime Achievement Award
  • DIRECTORIES
    • Buyer's Guide
    • Equipment Directory
    • Materials Directory
  • EMAGAZINE
    • Current Issue
    • eMagazine Archive
    • China Issue Archive
    • Editorial Advisory Board
  • CONTACT
    • Contact Us
    • Advertise
    • Subscribe to eMagazine
    • Subscribe to eNewsletters
  • SIGN UP!
Paint and Coating Resins & PolymersArchitectural CoatingsFinished Products

Early Rain Resistance Marks Next Step in Evolution of Elastomeric Roof Coatings

By George Daisey
pci1112-Dow-1-615.jpg
pci1112-Dow-2-615.jpg
pci1112-Dow-1-615.jpg
pci1112-Dow-2-615.jpg
December 3, 2012
First, it was adhesion to multiple substrates, then the requests were for better dirt pick-up resistance. Now, contractors are asking for – and receiving – an elastomeric roof coating that has the potential to resist hard rain much faster than previous technologies enabled.
Roof Coating Tips
Benefits of Elastomeric Roof Coatings
Applying Elastomeric Roof Coatings 
Formulation and Application Tips

As many commercial building owners and operators know, there are numerous benefits to applying elastomeric roof coatings (ERCs) to low-slope and flat roofs. For instance, ERCs can extend the service life of roofs and lower their overall lifecycle costs. Another benefit is reducing a roof’s heat load. The white roof coating reflects light, which helps to keep buildings cooler, thus reducing expensive air conditioning costs. With growing interest in energy efficiency and the urban heat island effect, many municipalities are encouraging ERC applications through various programs and incentives.

While the end-result benefits are widely known, there’s still one application obstacle many roof coating contractors have had to overcome in the past – the weather. Today, a new technology is helping to minimize this obstacle so contractors can coat roofs quickly and more easily. RHOPLEX™ EC-3000, a 100% acrylic polymer, was developed to address the need for improved hard rain resistance in ERCs. It helps set to the point of hard rain resistance in about 20 minutes.

ERC Performance Properties and Benefits

Many roof coating contractors are familiar with the sinking feeling that comes when rain and thunder clouds roll in during the middle of a coating application. If the coating isn’t set when the rain hits, the results can be ugly and the callbacks costly. Conventional water-based roof coatings take up to eight hours to dry to the point of hard rain resistance, therefore, rain that falls within eight hours of a crew leaving a job can wash the coating off the roof and create a huge mess to clean up. To help solve the needs of coating contractors in these situations, Dow investigated how to accelerate the fast set of ERCs, starting with – and building on – the company’s advances in acrylic chemistry.

Acrylics are well-known for their durability. When they are used in ERCs and fully cured, they extend the life of the roof by protecting the underlying substrate from degradation caused over time by exposure to rain, snow, wind and UV light. To achieve these benefits, the acrylic coating must be strong and durable, but it also has to have the ability to expand and contract with the substrate. Even within a single 24-hour period, a roof can undergo dramatic shifts in surface temperature, especially in temperate climates. Hot summers, cold winters and the variable bridge seasons of spring and autumn (when daytime heating from the sun alternates with significant nighttime cooling) all contribute to roof movement and mechanical stress. The ERC must be able to move with the roofing substrate – bridging and spanning small cracks that can develop as the temperature fluctuates.

While first-generation ERCs were elastic and flexible, they adhered to only a handful of roofing materials and required unique formulations for each type. Contractors had to use different coating materials for different substrates – creating an extra step and adding time to the application process. Today, 100% acrylic binders, like RHOPLEX EC-2885 and others, offer excellent adhesion to a wide range of substrates, including asphalt, concrete, metal, rubber, aged PVC, synthetic membrane, modified bitumen and even polyurethane foam.

Elasticity is another critical performance property of ERCs and relies on the use of a soft binder. In early version ERCs, soft binders also meant tacky binders. ERCs made with tacky binders had poor dirt pick-up resistance – meaning the coatings dulled quickly and required cleaning or re-coating to restore their white color and resulting reflectivity. With increasing awareness of cool roofs and increasing interest in more affordable cooling, dirt pick-up resistance has became an important performance property of ERCs and was incorporated into binders, such as RHOPLEX EC-1791, to keep roofs white and reflective.

Today, water-based ERCs using 100% acrylic binders offer many benefits to both the coating applicator and the building owner. Typically, these ERCs retain excellent elasticity at temperatures as low as -15 °F (-26 °C). They are expected to adhere to multiple types of substrates, and they offer better dirt pick-up resistance than their predecessors. They also are meant to facilitate formulations with <50 g/L VOCs. When fully cured, they act as long-term, durable barriers against rain, snow, wind and UV light. With regular maintenance, including re-coating every 10 to 15 years, a coated roof could potentially last for the lifetime of the building underneath it. While this is all good news for the building owner, it still doesn’t solve weather-related application challenges for the roof coating contractor.

A Longer Application Season

High humidity and low temperatures increase coating dry time, and rain can wash away or damage a coating that hasn’t cured.

Applying an ERC that sets quickly is crucial in geographies where humidity and rain accompany either a warm or cool climate throughout much of the year. However, conventional water-based acrylic ERCs require four to eight hours drying time to be considered rain-resistant, and even most quick-set acrylic technologies need at least an hour to set and, even then, resistance is limited to light rain and dew formation. RHOPLEX EC-3000 goes several steps further with next-generation, quick-set polymer technology.

The quick-set technology in EC-3000 accelerates the first phase of film formation by creating a gel structure that imparts immediate tensile strength in as little as 20 minutes after application. The coating isn’t completely cured at this stage, but it’s tough enough to remain intact even during a sudden heavy rain. In other words, it won’t run off or bubble up as with other ERCs. When it stops raining and the sun comes out, the water continues to evaporate and the coating continues to dry as normal.

While reducing rain delays and water washouts were the major impetus behind developing accelerated quick-set technology, the new chemistry in RHOPLEX EC-3000 can also help contractors extend their application season. In some parts of the United States, contractors may stop applying roof coatings in the middle of October because they take too long to dry in cool weather. But with the faster setting technology in EC-3000, it’s possible to extend the application season into November, as well as to start earlier the following spring. In certain circumstances, EC-3000 technology is known to extend the shoulder seasons by two to four weeks at either end. So not only does it help provide the benefit of heavy rain resistance, it also offers roof coating applicators another way to maximize their seasons.

Formulation and Application Tips

At the formulation stage, formulators who use RHOPLEX EC-1791 can often use EC-3000 as a drop-in replacement for the EC-1791, without having to change their current formulations. There also is a starting-point formulation for EC-3000 that can be followed.

To achieve the best application results, ERCs based on RHOPLEX EC-3000 technology should be applied by brush, roller or spray-application on polyurethane foam, metal, concrete, or aged asphalt roofs. These coatings should be applied at a minimum of 18-20 dry mil thickness (about 2.5 gallons per square) in two passes – allowing usually four or more hours under normal conditions between passes before applying the second coat. Water-based coatings based on EC-3000 should be applied at temperatures of 50 °F (10 °C) and rising, and not when temperatures fall below 40 °F (5 °C). ERCs based on EC-3000 should also not be applied at very high (>90%) relative humidity or when rain has already begun, when impending rain is expected to last more than one hour, or on roofs collecting ponded water. As you might expect, applicators must know the weather conditions on the day of application and understand how to modify the above application recommendations to facilitate a properly applied ERC job.

From improved adhesion to higher dirt pick-up resistance, advances in acrylic binder chemistry have elevated the performance of ERCs, with a ripple effect on consumer demand. With continued improvements like early rain resistance in RHOPLEX EC-3000, formulators and roof coating contractors will have the tools they need to keep up with demand. 

*This information is offered in good faith for your consideration, but without guarantee or warranty (express or implied), as analytical conditions and methods of use of the information and materials described herein may vary and are out of Dow’s control. Although this information is based on data Dow believes to be reliable and accurate, we do not intend for you to use, and you therefore should not construe, the contents of this document as business, technical or any other form of advice. We recommend you determine the suitability of the information and materials described herein before adopting or using them on a commercial scale. Dow assumes no liability in connection with the use of this information.

®™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow.

KEYWORDS: Acrylic Resins Protective Coatings Roof Coatings

Share This Story

Looking for a reprint of this article?
From high-res PDFs to custom plaques, order your copy today!

Daisey is a Research Scientist | The Dow Chemical Company, Spring House, PA

Recommended Content

JOIN TODAY
to unlock your recommendations.

Already have an account? Sign In

  • pci1022-Kinaltek-Lead-1170.jpg

    A Novel Pigment Production Technology

    Following an extensive R&D program that demonstrated...
    Paint and Coating Pigments
    By: Jawad Haidar and Nitin Soni
  • pci global top 10

    2025 Global Top 10: Top Paint and Coatings Companies

    The following is PCI’s annual ranking of the top 10...
    Paint and Coating Market Reports
    By: Courtney Bassett
  • 2025 pci 25

    2025 PCI 25: Top Paint and Coatings Companies

    PCI's annual ranking of the top 25 North American paint...
    Global Top 10 and PCI 25
    By: Courtney Bassett
You must login or register in order to post a comment.

Morra Davis
April 11, 2014
This is impressive. I am fascinated by the fact that new improved materials are being created and used in this industry to make things easier for us. It really pays to be informed, especially in this case. I usually keep myself updated by checking this www.roofdepotpros.com resource.

Aglaia Loved
April 14, 2014
I spoke with a guy from RLC a few month ago and he told me about this new coating created for roofs. I am building a house for my parents and i want to use the latest materials that have appeared on the market, especially if they are eco friendly.

Aglaia Loved
April 17, 2014
I will show this to my dad, he works in the real estate business and he is constantly looking for what's new in the field. I already showed him Bytheyard.net and i think that this article will also get his interest up.

Editor

Kristin Johansson
April 17, 2014
Thanks for all of the comments!

Fluttur Loves
May 7, 2014
I first heard of elastomeric roof coatings from The Flag Company and I must admit that I was skeptical at first. They seemed too much trouble to be worth it. Still, after going over the data, and seeing the substantial improvement in durability, I became a great supporter of this technology.

Tom Copper
May 19, 2014
I haven't seen the elastomeric roof coatings in action just yet but I'd like to and maybe if you click here you'll find some more information about the latest technologies in home comfort.

Roger Beiden
May 19, 2014
Getting a quality roof for your house from the very beginning is a wise thing. I've been looking at S B Restoration and their portfolio and some of their most challenging projects involved fixing old, leaky roofs.

Report Abusive Comment

Manage My Account
  • eMagazine
  • eNewsletter
  • Online Registration
  • Subscription Customer Service

CTT Registration Now Open

CTT Registration Now Open

The Coatings Minute: Your Inside Look at PCInnovations

The Coatings Minute: Your Inside Look at PCInnovations

The Coatings Minute: Print Returns with PCI’s New Showcase Issue

The Coatings Minute: Print Returns with PCI’s New Showcase Issue

The Coatings Minute: Your Guide to the 2025 Coatings Supplier Handbook

The Coatings Minute: Your Guide to the 2025 Coatings Supplier Handbook

More Videos

Sponsored Content

Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the PCI audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of PCI or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

close
  • Modern arapartment complex painted in bright colors.
    Sponsored byEPS - Engineered Polymer Solutions

    Architectural Polymers Leading the Way in Coatings Innovation

  • paint sprayer in a workshop
    Sponsored byallnex

    Enabling Performance and Compliance: allnex Introduces a New Line of VOC Exempt Solvent-Borne Resins

Popular Stories

BASF SE Logo

BASF Reportedly Eyes Exit from Coatings

No. 7 BASF Coatings

BASF Comments on Potential Sale of Coatings Business

No. 3 AkzoNobel

AkzoNobel’s $1.4B Divestment Signals Strategy Shift



PCI Buyers Guide

Submit a Request for Proposal (RFP) to suppliers of your choice with details on what you need with a click of a button

Start your RFP

Browse our Buyers Guide for manufacturers and distributors of all types of coatings products and much more!

Find Suppliers

Events

September 3, 2025

Coatings Trends & Technologies Summit

The Coatings Trends & Technologies (CTT) Summit is an annual conference for both liquid and powder coatings formulators and manufacturers to discuss innovations in coatings technology. This event combines high-quality technical presentations, a resource-rich exhibit hall, and dedicated networking opportunities to connect scientific minds, foster innovation, and cultivate game-changing new ideas!

January 1, 2030

Webinar Sponsorship Information

For webinar sponsorship information, visit www.bnpevents.com/webinars or email webinars@bnpmedia.com.

View All Submit An Event

Poll

Longest-running laboratory experiment

What is the longest-running laboratory experiment?
View Results Poll Archive

Products

CTT Summit Short Courses (Live 9/3/25)

Coatings Trends & Technologies Summit is expanding its offerings with four short courses. These short courses will offer an extensive day of interactive learning.

See More Products
pci voices from the top ebook

PCI CASE EBOOK

Related Articles

  • Akzo Nobel Says New China Office Marks Next Step in Expansion Program

    See More
  • pci0522-EPS-1149754751-1170.jpg

    Dirt-Pickup Resistance in Low-Tg Elastomeric Coatings

    See More
  • evonik

    The Next Step in Wood Coatings

    See More

Related Products

See More Products
  • durability.jpg

    Increasing the Durability of Paint and Varnish Coatings in Building Products and Construction 1st Edition

  • corrosion of linings.jpg

    Corrosion of Linings & Coatings: Cathodic and Inhibitor Protection and Corrosion Monitoring

  • failiure-analysis-of-paints

    Failure Analysis of Paints and Coatings, Revised Edition

See More Products

Events

View AllSubmit An Event
  • March 5, 2025

    Fibrillated Cellulose Boosts Mechanical, Surface & Rheology Performance of Elastomeric Roof Coatings

    On Demand The topic of this webinar will be the use of Valida fibrillated cellulose in Elastomeric roof coatings.
View AllSubmit An Event
×

Keep the info flowing with our eNewsletters!

Get the latest industry updates tailored your way.

JOIN TODAY!
  • RESOURCES
    • Advertise
    • Contact Us
    • Directories
    • Store
    • Want More
  • SIGN UP TODAY
    • Create Account
    • eMagazine
    • eNewsletters
    • Customer Service
    • Manage Preferences
  • SERVICES
    • Marketing Services
    • Reprints
    • Market Research
    • List Rental
    • Survey & Sample
  • STAY CONNECTED
    • LinkedIn
    • Facebook
    • Youtube
    • X (Twitter)
  • PRIVACY
    • PRIVACY POLICY
    • TERMS & CONDITIONS
    • DO NOT SELL MY PERSONAL INFORMATION
    • PRIVACY REQUEST
    • ACCESSIBILITY

Copyright ©2025. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing

Painting & Coating Industry (PCI) logo Powder coating summit logo
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Painting & Coating Industry (PCI) logo Powder coating summit logo
  • NEWS
    • Latest News
    • Market Trends & Reports
    • Price Alerts
    • Subscribe to eNewsletters
    • Global Top 10/ PCI 25
    • Weekly Featured Article
    • COATLE Word Game
  • PRODUCTS
    • Product News
    • Must See Products and Services
  • MATERIALS
    • Additives
    • Resins/Polymers
    • Pigments
    • Equipment
    • Distributors
  • TECHNOLOGIES
    • Adhesives
    • Architectural Coatings
    • FINISHING
      • Finishing News
      • Finishing Technologies
      • Finishing Equipment
      • Finishing Today
    • Industrial Coatings
    • Nanotechnology
    • Powder Coatings
    • Solventborne
    • Special Purpose Coatings
    • Sustainability
    • UV Coatings
    • Waterborne
  • RESOURCES
    • Columns
      • Ask Joe Powder
      • Did you know?
      • Distribution Dive
      • Focus on Canada
      • Formulating With Mike
      • Innovation Insights
      • Moody's Coatings Conundrums
      • Powder Coating Perspectives
      • Target the Market
      • TiO2 Insider
    • Blogs
      • Editor's Viewpoint
      • Industry Insights
    • Coatings Supplier Handbook
    • Podcasts and Videos
      • COAT-IT! Podcast
      • Videos/PCI TV
    • PCI Store
    • Classifieds
    • eBooks
    • Sponsor Insights
    • White Papers
    • COATLE Word Game
  • EVENTS
    • Coatings Trends & Technologies Summit
    • Paint and Coatings Academy
    • Webinars
    • Calendar of Events
    • Lifetime Achievement Award
  • DIRECTORIES
    • Buyer's Guide
    • Equipment Directory
    • Materials Directory
  • EMAGAZINE
    • Current Issue
    • eMagazine Archive
    • China Issue Archive
    • Editorial Advisory Board
  • CONTACT
    • Contact Us
    • Advertise
    • Subscribe to eMagazine
    • Subscribe to eNewsletters
  • SIGN UP!