Common Mistakes in Intumescent Coating Application and How to Avoid Them

Firemen Extinguishing the Fire

Intumescent coatings are an essential part of fire protection, especially in industrial and commercial buildings. However, improper application can compromise their effectiveness, leaving structures vulnerable. Here are some common mistakes made during intumescent coating application and how to avoid them:

 

1. Improper Surface Preparation

One of the most frequent mistakes is applying intumescent coatings to improperly prepared surfaces. If the substrate (typically steel) is not cleaned or primed correctly, the coating may not adhere properly, leading to poor fire protection performance.

How to Avoid:
Ensure the surface is clean, free from rust, dirt, or old paint, and is primed with a compatible primer. Follow the manufacturer’s instructions on surface preparation to ensure the coating bonds properly.

 

2. Incorrect Thickness of Application

Intumescent coatings need to be applied at the correct thickness to provide the required level of fire resistance. Applying too little or too much can affect the coating’s ability to perform as intended during a fire.

How to Avoid:
Use specialised measuring tools such as wet film thickness gauges to ensure the correct thickness. Follow the manufacturer’s guidelines for the number of coats required to achieve the desired thickness.

 

3. Environmental Conditions

Temperature, humidity, and wind can significantly affect the application process. Applying intumescent coatings in unsuitable conditions may result in improper curing, cracking, or peeling.

How to Avoid:
Check the environmental conditions before application. Most manufacturers specify a temperature and humidity range for proper application and curing. Work indoors or in controlled environments when possible to avoid adverse conditions.

 

4. Skipping the Recoat Time

Many applicators fail to adhere to the recommended recoat times between layers, resulting in improper bonding between layers. This can lead to reduced fire protection performance.

How to Avoid:
Follow the recoat time specified by the coating manufacturer. Ensure that each layer is fully dry and cured before applying the next.

 

5. Neglecting Maintenance After Application

Once applied, intumescent coatings may require regular maintenance checks to ensure they remain effective over time. Physical damage, moisture, and wear can reduce their fire protection capabilities.

How to Avoid:
Schedule routine inspections and maintenance. If any damage or wear is detected, promptly repair or reapply the coating to maintain its fireproofing properties.

 

6. Failure to Use Approved Application Techniques

Improper application techniques, such as using unsuitable spray equipment or applying the coating unevenly, can result in poor coverage and reduce fire resistance.

How to Avoid:
Ensure you use the recommended application tools, such as airless spray systems or rollers, as advised by the manufacturer. Train applicators on proper techniques to achieve an even coat and full coverage.

 

7. Not Following Manufacturer Specifications

Every intumescent coating product has specific application requirements, including compatibility with primers and topcoats, application methods, and curing times. Failing to follow these specifications can render the fireproofing ineffective.

How to Avoid:
Always consult the manufacturer’s technical data sheets and follow their guidelines precisely. If unsure, reach out to the manufacturer for clarification before beginning the application process.

Intumescent coatings are a highly effective fire protection measure, but their performance depends heavily on proper application. By avoiding these common mistakes—such as improper surface preparation, incorrect thickness, and ignoring environmental conditions—you can ensure the coating delivers optimal fire resistance. Proper training, adherence to manufacturer guidelines, and regular maintenance are key to a successful application that keeps structures safe in the event of a fire.