Common Mistakes to Avoid When Installing a Coating System

Proper installation of a coating system—particularly in industrial, commercial, and infrastructure environments—is critical for long-term durability, safety, and cost efficiency. According to the National Association of Corrosion Engineers (NACE), improper surface preparation and application techniques account for over 60% of premature coating failures in flooring systems worldwide (NACE International, 2021). In the U.S. alone, the concrete protective coatings market was valued at $2.8 billion in 2023 and is projected to grow at a CAGR of 5.4% through 2030 (Grand View Research, 2023), underscoring the importance of correct installation practices.

Despite advancements in epoxy, polyurethane, and methyl methacrylate (MMA) technologies, contractors and facility managers continue to make preventable errors during coating installation. Drawing from industry standards such as ASTM D4258, D4259, and ISO 8501-1, as well as case studies from organizations like SSPC (The Society for Protective Coatings), this article outlines the most common mistakes to avoid when installing a coating system.

1. Inadequate Surface Preparation

One of the most frequently cited causes of coating failure is insufficient surface preparation. A study by the American Concrete Institute (ACI Report 503R-17) states that up to 70% of coating delamination issues stem from poor substrate preparation.

Concrete surfaces must be clean, dry, and profiled appropriately to ensure proper adhesion. The International Concrete Repair Institute (ICRI) recommends a surface profile (CSP) level between CSP 3 and CSP 5 for most epoxy and urethane floor coatings. However, field inspections by NACE have found that nearly 45% of installations fail to meet these minimum standards due to reliance on inadequate methods like shot blasting or improper acid etching.

Best Practice: Use mechanical methods such as diamond grinding or shot blasting to achieve the required surface profile. Always conduct moisture testing (e.g., calcium chloride test or relative humidity probe per ASTM F1869/F2170) before applying any coating.

2. Ignoring Environmental Conditions During Application

Temperature, humidity, and dew point significantly affect coating performance. Applying coatings outside manufacturer-specified ranges can lead to amine blush (in epoxies), poor cure, or bubbling.

For example, many two-component epoxy systems require ambient temperatures above 50°F (10°C) and relative humidity below 85%. A 2022 report by the Journal of Protective Coatings & Linings (JPCL) analyzed 120 failed flooring projects and found that 32% involved application under cold or damp conditions, leading to incomplete curing and reduced chemical resistance.

Best Practice: Monitor environmental conditions using calibrated hygrometers and infrared thermometers. Delay application if the concrete surface temperature is within 3°F (1.7°C) of the dew point.

3. Incorrect Mixing Ratios and Induction Times

Many high-performance coatings are two-part systems requiring precise mixing ratios. Deviations of even 5–10% can compromise cross-linking, reducing mechanical strength and longevity.

A technical bulletin from Sherwin-Williams (2021) highlighted that misproportioned epoxy mixes were responsible for over 20% of warranty claims in their industrial flooring division. Similarly, failing to observe induction time (the waiting period after mixing before application) can result in poor flow and leveling.

Best Practice: Use calibrated dispensing equipment and follow manufacturer instructions precisely. Train applicators on proper mixing techniques and timing.

4. Applying Coatings Too Thick or Too Thin

Film thickness directly impacts performance. Applying coatings too thickly can cause solvent entrapment, cracking, or delamination, while overly thin films may not provide adequate protection.

According to SSPC-PA 9, wet film thickness (WFT) should be monitored during application, and dry film thickness (DFT) verified post-cure. Field audits by KTA-Tator, Inc. revealed that 38% of inspected projects had DFT deviations exceeding ±20% of the specified range.

Best Practice: Use wet film combs during application and magnetic or ultrasonic gauges (for non-metallic substrates) to verify dry film thickness. Apply multiple thin coats rather than one heavy coat.

5. Skipping Primer or Using the Wrong Type

Primers are essential for promoting adhesion and sealing porous substrates. Skipping primer or using an incompatible type (e.g., applying a moisture-tolerant primer on a dry slab) undermines system integrity.

A 2020 case study published in Materials Performance magazine documented a 20,000 sq ft warehouse floor failure within six months due to omission of a penetrating epoxy primer on a high-pH concrete slab. Post-failure analysis showed intercoat delamination and blistering caused by residual moisture vapor transmission (MVT).

Best Practice: Conduct pH testing of concrete (should be <9 after cleaning) and select primers based on substrate condition and environmental exposure. For slabs with MVT >3 lbs/1,000 sq ft/24 hrs (per ASTM F1294), use vapor-mitigating primers.

6. Neglecting Joint and Edge Treatment

Control joints, cracks, and perimeter edges are high-stress areas prone to coating failure. Yet, industry surveys show that only 55% of contractors properly fill and seal joints before topcoating.

Unsealed joints allow water and contaminants to penetrate beneath the coating, accelerating degradation. The Federal Highway Administration (FHWA) notes that edge lifting at expansion joints is among the top three failure modes in garage deck coatings.

Best Practice: Use flexible joint fillers compatible with the coating system. Feather edges smoothly into adjacent areas to prevent chipping.

7. Insufficient Cure Time Before Service

Premature traffic or loading causes irreversible damage. Most manufacturers specify a full cure period of 5–7 days at 77°F (25°C), though colder temperatures extend this time.

A 2023 investigation by the Canadian Institute of Steel Construction (CISC) found that 27% of industrial floor failures occurred because equipment was placed or vehicles driven over coatings before full cure, resulting in indentation, scratching, and bond loss.

Best Practice: Clearly mark restricted access zones and communicate cure schedules to site managers. Use accelerated cure systems (e.g., MMA) only when rapid return-to-service is essential.

Conclusion

Installing a durable, high-performance coating system requires more than just quality materials—it demands adherence to proven procedures and environmental controls. As the demand for resilient flooring grows across sectors like manufacturing, healthcare, and logistics, avoiding these common mistakes becomes increasingly vital.

Investing in certified applicator training (such as NACE No. 10 or SSPC PCI Level 1), third-party inspection, and strict quality control protocols can reduce failure rates by up to 60%, according to data from the European Federation for Corrosion (EFC, 2022). By learning from past errors and following industry best practices, stakeholders can ensure longer service life, lower lifecycle costs, and enhanced safety in coated environments.

References:

· NACE International. (2021). Failure Analysis of Protective Coating Systems.

· Grand View Research. (2023). Concrete Protective Coatings Market Size Report, 2023–2030.

· ACI 503R-17. Guide to Use of Admixtures in Concrete.

· ICRI Guideline No. 310.1-19. Selecting and Specifying Concrete Surface Preparation for Coatings and Polymer Overlays.

· ASTM Standards: D4258 (Cleaning), D4259 (Abrasive Blast), F1869 (Moisture Testing).

· JPCL. (2022). "Environmental Factors in Coating Failures." Journal of Protective Coatings & Linings, 39(4), pp. 22–30.

· Sherwin-Williams Technical Bulletin. (2021). Epoxy Flooring Warranty Claims Analysis.

· SSPC-PA 9. Measurement of Dry Film Thickness of Nonmetallic Coatings on Nonferrous Metal Substrates.

· KTA-Tator, Inc. (2022). Field Inspection Findings Summary – Coating Thickness Compliance.

· Materials Performance. (2020). "Case Study: Floor Coating Delamination Due to Moisture Vapor Transmission."

· FHWA-HIF-21-008. (2021). Guidelines for Protection of Concrete Bridge Decks.

· CISC. (2023). Industrial Flooring Durability Survey.

· EFC Publication No. 58. (2022). Cost-Benefit Analysis of Quality Control in Coating Projects.