Quick Guide to Surface Preparation for Polyurea Coating
Polyurea’s rapid cure time and high performance mean there’s little margin for error. Without proper substrate preparation, you may end up with issues like delamination, blistering, and poor adhesion, resulting in expensive rework or failed applications.
Proper polyurea substrate preparation is key to a successful, long-lasting coating, minimal waste, and customer satisfaction. Careful attention to the surface will ensure the polyurea coating adheres properly and result in a high-quality finish that stands up to demanding environments.
Benefits of Proper Preparation
Successful polyurea coating jobs begin long before the spray gun is loaded and you start spraying. The quality of your surface preparation directly impacts the performance, appearance, and longevity of the coating.
“At Oak Ridge, we’ve seen it all, and we can say with confidence that 90% of coating failures trace back to poor prep,” said Bill Brabender, sales representative at Oak Ridge.
Stronger Adhesion
Proper surface preparation ensures that the polyurea forms a strong chemical and mechanical bond with your substrate. Without this bond, the coating may not “stick” and may lift, blister, or peel prematurely. Better adhesion means fewer callbacks and repairs, and happier customers.
Longer Lifespan of the Coating
When you properly clean and prime the area, the coating can perform to its full engineered potential. A well-bonded polyurea system resists delamination and breakdown over time, extending service life significantly. Prep it right, and your coating can last 10–20 years or more, even under extreme conditions and temperature fluctuations.
Better Resistance to Moisture, Abrasion, and Chemicals
The coating is only as strong as its bond. Prep creates a solid foundation that can handle what the job throws at it. Properly prepped and primed surfaces allow polyurea to form a continuous, monolithic barrier that resists infiltration and degradation.
Step-by-Step: How to Prepare a Surface for Polyurea Coating
Surface prep isn’t just a preliminary step—it’s the difference between a successful polyurea application and a costly failure. Before you fire up your equipment, it’s critical to assess, clean, profile, and prime your substrate with precision.
1. Identify the Substrate Type
Whether you’re coating concrete, steel, wood, or plastic, every material requires a tailored preparation approach. Take time to understand the substrate’s characteristics and vulnerabilities before beginning.
2. Mask and Protect Surrounding Areas
Use tape, sheeting, or barriers to shield non-target surfaces. This saves cleanup time and prevents accidental damage to nearby structures, equipment, or landscaping.
Also, don’t forget to mask and protect yourself! PPE is important when grinding, sanding, and solvent cleaning.
3. Clean the Surface Thoroughly
Remove all debris, including dust, grease, oils, rust, salt, and other contaminants. The cleaner, the better. You want to avoid contaminants getting stuck under the coating or impacting adhesion. Common cleaning methods include using solvents to remove oil and grease or pressure washing the area and letting it fully dry.
4. Remove Existing Coatings or Loose Material
In addition to cleaning the surface, get rid of any loose materials such as flaking paint, rust, scale, or previous coatings. Getting rid of all the extra material will help improve adhesion with your new coating. Sandblasting, grinding, or sanding can be helpful in removing coatings and loose material from metal, concrete, and wood.
5. Achieve the Correct Surface Profile
A proper surface profile increases the mechanical bonding between the material and the polyurea coating. The required roughness depends on the coating thickness and substrate type, so it’s best to check the manufacturer’s guidelines on the container or use our Technical Data Sheets library.
6. Dry the Surface
Ensure the substrate is completely dry, especially for porous surfaces like concrete. Moisture can significantly impact the coating results. Plan for plenty of dry time and use moisture meters to make sure the substrate is totally dry and ready to go.
7. Assess Ambient Conditions
Beyond surface prep, don’t overlook environmental factors like humidity and surface temperature.
Before you start, relative humidity should be below 85% and surface temperature should be at least 5°F above the dew point
Check both ambient and substrate temperatures per product guidelines
8. Apply the Right Primer Before Polyurea
Choosing the correct primer before polyurea enhances chemical bonding and blocks moisture or gassing from the substrate. While it’s important to review instructions and materials, in general, epoxy primers are great for concrete and metals, and urethane primers are good for wood or composite substrates.
Our primers include:
- OR 811: A single-component polyurea primer that contains a non–HAP solvent. It can be used on steel, aluminum, stainless steel, galvanized metal, wood, concrete, and a variety of other substrates.
- OR E41: A water-based, epoxy primer that’s supplied in two parts. Spray as a coating and/or primer for brick, asphalt driveways and parking lots, wood, vinyl floor tiles, concrete, EPDM and TPO roofing, aluminum and sheet metal roofing, and more.
9. Mix and Test Materials
Always mix thoroughly—especially with two-part primers—and conduct a small-area test spray. This helps confirm texture, adhesion, cure time, and gun settings before full application.
10. Do a Final Check Before Spraying
It’s almost time to start the coating process. Before you spray, it’s important to do one last check to make sure everything is good to go.
- Verify the ambient and surface temperatures
- Make sure there’s adequate ventilation (especially in indoor spaces)
- Perform an adhesion test if you’re uncertain
Bonus Tip: Document Everything!
Documenting your process can help you make sure you’re on track and help pinpoint the issue if something goes wrong.
We recommend you document key jobsite data, such as weather, moisture levels, surface profiles, and all materials used. As you go along, take photos and document each steps to ensure quality assurance and warranty tracking if necessary.
Common Mistakes to Avoid During Surface Preparation
Here are some common surface preparation mistakes to avoid:
Skipping The Primer Or Using The Wrong One
Skipping the primer or using the wrong type can result in poor chemical adhesion, delamination, or failure under stress. Always choose a substrate-compatible primer designed to enhance bonding and address issues like moisture vapor, porosity, or chemical resistance. When in doubt, test adhesion or consult with your supplier. If you have questions about a primer purchased from Oak Ridge, please contact us.
Not Achieving The Correct Surface Profile
The surface profile (roughness or texture) is critical for adhesion. If the surface is too smooth, the polyurea can’t grip. And if it’s too rough or inconsistent, you’ll end up with uneven thickness or material waste. Always refer to your coating system’s Technical Data Sheet (TDS) for specific profile requirements.
Rushing Preparation To Save Time
Proper prep takes time—but fixing a failed coating takes even longer. Time pressure is common on job sites, but polyurea’s quick cure rate doesn’t leave room for a second chance. Skipping or shortening surface prep can undo an otherwise perfect application, leading to premature failure and ultimately costing more time and money in the long run. Build adequate prep time into your project schedule and educate crews and your customers about why each step is necessary.
Oak Ridge Is Your Polyurea Coating Partner
With proper polyurea substrate preparation and the correct use of primer before polyurea, you’ll ensure that your application meets professional standards and keeps customers happy for years to come.
“Whether it’s spray foam insulation, specialty coatings, or repair materials, we’re committed to delivering the right products combined with expert advice to help you tackle any project effectively,” Bill said.
Need help selecting the right primer, coating, or spray coating equipment for your next job? Our team is here to provide expert advice and product recommendations specific to your project. We work with contractors nationwide, providing ongoing training, top-notch customer service, and high-quality equipment to help take your spray coating business to the next level.