Applying a roof coating is one of the most cost-effective ways to extend the life of your flat commercial roof. However, even the best coating products can fail prematurely if installed improperly. In fact, most early roof coating failures are not due to defective materials—but due to application mistakes.
At Boundless Roofing & Chimney, we’ve restored hundreds of commercial roofs across New Jersey and have seen firsthand what can go wrong. In this article, we’ll break down the top mistakes to avoid when applying a roof coating—and how to get the job done right.
1. Skipping Surface Preparation
This is the most common and most damaging mistake.
Applying a coating over a dirty, damp, or damaged surface prevents adhesion, leading to peeling, bubbling, or flaking within months.
What to do instead:
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Power wash the entire roof with 3,000+ PSI
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Remove all dirt, grease, and loose debris
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Let the surface dry completely
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Perform repairs on any cracks, seams, or blisters
✅ Tip: Don’t just “rinse” the roof—deep cleaning is required for proper adhesion.
2. Coating Over Moisture or Trapped Water
Applying roof coating over a wet or moisture-damaged substrate is a recipe for failure. Moisture trapped under the membrane will evaporate over time, creating blisters or bubbles in the coating.
What to do instead:
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Use a moisture scanner to detect hidden wet areas
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Allow the roof to fully dry
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Replace wet insulation or roofing sections if needed
✅ Tip: Flat roofs in NJ often experience ponding—address drainage issues before coating.
3. Using the Wrong Coating for the Roof Type
Not all coatings are compatible with every roofing system. For example, acrylic doesn’t perform well on roofs with ponding water, and some membranes require special primers.
What to do instead:
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Choose the coating that matches your roof type (TPO, EPDM, mod-bit, metal, etc.)
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For ponding water, use silicone, not acrylic
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Always follow manufacturer compatibility guidelines
✅ Tip: Have a certified roofing contractor evaluate your roof and recommend the right product.
4. Ignoring Manufacturer Specs
Every roof coating system has specific application instructions, including:
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Required mil thickness (wet and dry)
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Curing times
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Temperature and humidity conditions
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Number of coats
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Application method (spray vs. roller)
Cutting corners here can void your warranty and reduce the lifespan of the coating.
What to do instead:
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Follow the manufacturer’s data sheets exactly
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Use the correct equipment and technique
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Maintain even coverage across the entire roof
✅ Tip: Always document the mil thickness with a gauge during installation.
5. Applying in the Wrong Weather Conditions
Roof coatings need the right temperature and dry weather to cure properly. Applying in cold, rainy, or humid conditions can cause wash-off, poor adhesion, or improper curing.
What to do instead:
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Apply coatings when the weather is dry and temperatures are between 50°F and 85°F
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Avoid application if rain is expected within 24–48 hours
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For winter work, choose cold-weather formulations
✅ Tip: Check both daytime highs and overnight lows before scheduling the job.
6. Not Repairing the Roof First
Roof coatings are designed to restore a surface, not fix structural problems. Coating over failing seams, saturated insulation, or cracked membranes will hide the problem, not solve it.
What to do instead:
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Inspect the roof thoroughly
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Repair all known leaks and damages
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Ensure the substrate is sound before coating
✅ Tip: If your roof is too damaged, a full replacement may be a better investment.
7. Improper Flashing and Detail Work
The most vulnerable parts of any roof are seams, penetrations, and flashing details. Failing to reinforce these areas properly can lead to leaks—despite a good surface coating.
What to do instead:
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Reinforce flashing and penetrations with mesh, sealant, or fabric
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Follow a “three-course” system where needed
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Pay extra attention to HVAC curbs, drains, skylights, and parapet walls
✅ Tip: Don’t overlook the edges. Perimeter detailing is key to watertight performance.
8. Underapplying the Coating (Too Thin)
One of the biggest mistakes is applying too little product. Thin coatings fail faster, crack sooner, and won’t meet warranty specs.
What to do instead:
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Measure and record the coating’s wet mil thickness
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Apply enough material for a minimum 20–30 mil dry film thickness, as required
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Consider applying in two coats for durability
✅ Tip: Skimping on coating thickness often leads to premature re-coating costs.
9. Neglecting Warranty Requirements
Even if the coating is applied properly, you can lose warranty coverage if you fail to register it or follow the post-installation maintenance guidelines.
What to do instead:
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Use a manufacturer-certified installer
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Register the warranty promptly
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Schedule annual inspections to stay compliant
✅ Tip: At Boundless Roofing & Chimney, we handle all warranty paperwork for you.
10. Hiring an Inexperienced Contractor
Finally, one of the worst mistakes is trusting your roof to a contractor who lacks experience with commercial coatings. These systems require knowledge of surface prep, flashing detail, mil thickness, and weather conditions.
What to do instead:
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Choose a contractor with proven coating experience
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Ask for references, project photos, and warranty details
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Make sure they are certified by the coating manufacturer
✅ Tip: Boundless Roofing & Chimney is certified in multiple commercial coating systems and offers full labor + material warranties.
Avoid Costly Mistakes—Hire the Pros
When applied properly, a commercial roof coating can give your roof an additional 10–20 years of life. But skipping steps, using the wrong product, or hiring the wrong installer can cost you far more in the long run.
At Boundless Roofing & Chimney, we specialize in flat roof restoration across New Jersey. From prep to finish, we ensure every job meets:
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Manufacturer specs
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Warranty standards
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Energy efficiency goals
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Budget and scheduling needs
📞 Call us now at 973-960-7921
📩 Or request your free roof coating estimate
Final Takeaway
Applying a roof coating might seem straightforward—but avoiding these common mistakes is what separates a long-lasting investment from a short-term fix. Trust the experts at Boundless Roofing & Chimney to get it right the first time.