Avoid These Common Mistakes in Commercial Coating Applications

Whether you are a Veteran or a novice in the commercial coating industry, there is always an opportunity to improve your craft and increase your knowledge of the application process itself and how the chemicals react during this process. We've taken the time to identify the top questions asked regarding errors in the application and whether there is a way to correct without costing your company time, resources, and profit it has earned. 

Common Mistakes in Polyurea Coating Application

The most common mistakes in polyurea coating applications stem from poor surface preparation, incorrect moisture testing, improper mixing, and applying layers too thick or too thin. These often lead to delamination, bubbling, and curing failures, and more often than not, are completely preventable. It is imperative to remember that when dealing with polyurea coatings, no two applications will be the same. Make sure you are following the manufacturer guidelines as well as ensuring you are following temperature guides, pressure output needed, and monitoring the current moisture, even if you just tested it at the service quote.

Surface Prep for Polyurea Coatings

1. Clean and Degrease - Use specialized cleaning products to remove any oils, grease, or dirt, followed by a thorough water wash.
2. Grinding/Shot Blasting - Diamond grinding is essential to remove the top layer of laitance and open the pores for maximum mechanical bonding.
3. Repair any Damages - Fill cracks and bug holes with a compatible polyurea filler, grinding the surface smooth after curing.
4. Moisture Testing - Ensure the concrete is fully cured and dry, as high moisture can cause adhesion failure and other issues!
5. Dust Removal - Use an industrial HEPA-Filtered vacuum to remove all the dust, as it will hinder the bonding process in curing.
6. Surface Tension Test - This is the FINAL test. Perform a water bead test; if the water beads up, the surface will require more cleaning or grinding. If the water does not bead - you are okay to proceed with your application. 

Temperature and Humidity Requirements for Polyurea

The optimal conditions are typically temperatures between 50F and 90F with a relative humidity level between 40% and 60%. While Polyurea is known for its versatility in extreme conditions, following these guidelines ensures that there will be proper curing, adhesion, and performance for the final product. If the temperature is too low, the curing rate slows significantly and risks incomplete reactions during application. There are polyurea systems that CAN be applied during sub-zero temperatures, so make sure to verify your system type needed prior to application. If the temperature or humidity gets too high, you risk your polyurea application curing too quickly, risking pinholes, bubbles, and uneven surface finishes.

Sidenote: The substrate temperature needs to be at least 5 degrees above the dew point to prevent condensation during the application. You can check on your favorite weather app to see what the current dew point is for each respective day when trying to plan your application.

Course Correct: Common Issues with Incorrect Application

How to fix soft or tacky polyurea coating?

Tacky or gummy polyurea coatings are indicative of improper mixing during the application process. Failing to achieve a proper ratio, such as mixing too fast or having the incorrect A/B ratio, can cause soft, uncured, or "gummy spots." Can this be fixed post-application? For severe, widespread, or deep-seated tackiness, the only solution for correction is to remove the entire layer, sand, and reapply the coating entirely. For smaller areas or "spot" correction, you will need to scrape off the damaged area and use acetone or denatured alcohol to clean up the residue. Once the residue is removed, clean the surface thoroughly to ensure the new layer bonds. Now you are ready to reapply a properly mixed layer of Polyura.

Ployurea coating blistering and pinholes.

So, you've got blistering and pinholes forming? This is most likely caused due to trapper moisture or vapors during your application and curing process. When vapors get trapped under or within the fast-curing polyurea coating, it will create pinholes and bubbles. If this happened to you during your application, there are a couple of ways that you can correct this without having to redo the entire area. This process involves grinding out the damaged areas, ensuring the substrate is completely dry, and resealing with a compatible coating or filler. Once this step is complete, be sure to prime the area with a re-coat, such as Polyprime U, to seal the substrate. Once your primer has cured, you can then apply a new topcoat to the repaired areas.

Polyurea Peeling from Concrete Surface.

Inadequate surface prep or delamination is typically caused by skipping the grinding process or shot-blasting, resulting in a smooth surface that can not hold the coating. When your surface prep is less than complete, it can lead to the cured coating lifting from the concrete in sheets or trapping air bubbles. NEVER SKIP THE SITE PREP!

Substrate Moisture Impact on Polyurea.

You can not ignore the moisture! Substrate moisture is critical for polyurea, requiring a level below 8% or, ideally, a moisture vapor emission rate (MVER) under 3-5 pounds/1000 sq feet per 24 hours. Excess moisture can cause adhesion failure, bubbling, blistering, and delamination due to vapor pressure. While Polyurea is moisture-tolerant during curing, high substrate moisture ruins long-term bond strength and substrate adhesion. Use a vapor barrier to ensure proper curing! NEVER SKIP YOUR MOISTURE CHECKS!

We hope that you were able to find the answers you were looking for today regarding your polyurea coating application. Proper site preparation, moisture checks, and weather all play a huge factor in getting the best application. We want to help you troubleshoot any issues before it costs YOU and your business. In the end, Polyurea is an amazing product and can help preserve and protect your commercial flooring, roofing, and more.

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