Peeling and bubbling in industrial floor coatings often stem from similar root causes but can manifest differently depending on the coating chemistry and application environment. Understanding the interplay between substrate conditions, environmental factors, and coating type is key to diagnosis and prevention.
Common Causes of Peeling/Bubbling
- Moisture Vapor Emission: Epoxy is a dense, impermeable coating. When applied over concrete with high moisture or hydrostatic pressure, trapped vapor creates bubbles and blisters.
- Poor Surface Preparation: Epoxy requires a clean, roughened surface (typically a CSP 3-5 profile from shot blasting). Any residual laitance, oils, or contaminants reduce adhesion.
- Incorrect Mix Ratios or Pot Life: Epoxy requires precise mixing of resin and hardener. Off-ratio or expired material leads to improper curing and weak bonding.
- Temperature and Humidity Issues: Applying epoxy below 10°C or when relative humidity exceeds 85% can cause incomplete cure or condensation.
- Always perform moisture tests (calcium chloride or RH probes) and ensure moisture content < 3 lbs/1000 sq ft/24 hours.
- Prepare surfaces by shot blasting to specified profile.
- Use epoxy primers with moisture-tolerant formulations if moisture is a concern.
- Maintain ambient and substrate temperature within recommended ranges.
- Mix and apply epoxy strictly following manufacturer instructions.
Common Causes of Peeling/Bubbling
- Moisture Sensitivity During Application: Polyurethane coatings are more flexible and UV stable but sensitive to moisture during curing, leading to bubbles.
- Surface Contamination: Oil or grease on substrate causes adhesion failure.
- Over-application or Poor Ventilation: Thick layers without proper ventilation can trap solvents, causing bubbling.
- Clean substrate thoroughly to remove all contaminants.
- Avoid application in high humidity or rain-prone environments.
- Apply thin, even coats and ensure proper ventilation for solvent evaporation.
- Use moisture-tolerant PU primers on damp surfaces.
Common Causes of Peeling/Bubbling
- Very Fast Cure Time: Polyurea cures rapidly, which can cause bubbles if surface moisture or contaminants are present.
- Substrate Moisture: High moisture or dampness can cause blistering beneath the coating.
- Insufficient Surface Profiling: Smooth or unprepared surfaces cause adhesion problems.
- Thorough surface profiling and moisture testing.
- Apply coatings immediately after surface preparation to avoid dust or contamination.
- Control temperature and humidity tightly.
- Use primers if recommended for improved adhesion.
Common Causes of Peeling/Bubbling
- Rapid Cure Generating Heat: MMA cures fast with exothermic reaction, and thick applications may cause bubbling due to heat and solvent vapor.
- Moisture Trapping: Moisture in substrate leads to vapor pressure issues.
- Surface Contamination or Poor Profiling: Prevents bonding.
- Apply in thin layers and avoid thick build-ups.
- Moisture testing and substrate drying before application.
- Maintain proper ventilation to dissipate heat and vapors.
- Thorough surface preparation by grinding or shot blasting.
Common Causes of Peeling/Bubbling
- Poor Adhesion to Concrete: Acrylics can fail on smooth or dirty surfaces.
- UV and Weathering Effects: Acrylic coatings may degrade over time causing surface failures.
- Moisture Sensitivity: Acrylics are more permeable but can still bubble under excessive moisture.
- Proper surface cleaning and roughening.
- Use acrylic primers if required.
- Avoid application in extreme weather (too hot, too cold, or humid).
- Regular maintenance to extend lifespan.
| Problem | Possible Cause | Recommended Action |
| Peeling at edges | Poor adhesion or contamination | Re-profile edges, clean thoroughly, reapply primer |
| Large blisters | Moisture vapor emission | Moisture mitigation, install vapor barrier, select moisture-tolerant coating |
| Small bubbles | Air entrapment or solvent off-gassing | Adjust application technique, improve ventilation |
| Surface tacky after cure | Incorrect mix or cold temperature | Check mix ratio, maintain correct temperature |
| Discoloration | UV exposure or chemical attack | Use UV-resistant topcoat or select more durable coating |
- Always perform thorough moisture testing before coating.
- Ensure mechanical surface preparation to remove contaminants and provide proper profile.
- Follow manufacturer guidelines for mixing, application temperatures, and curing.
- Select coating systems based on environmental conditions and floor use.
- Maintain environmental controls during and after application to avoid condensation and humidity problems.
- Use primers and vapor barriers where needed to manage moisture.
- Schedule regular inspections and maintenance to prolong coating life.
US 7385 
BR 2513 
CA 1659 
AU 1655 
TH 1566 
JP 1473 
SG 1248 
HK 784 
