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What is intumescent painting and why does my project need it?

Intumescent paint application

In the UK, it’s the law to apply intumescent paints to all load bearing steel structures in commercial and industrial buildings. But what are intumescent paints and why are they so important to get right? Read on to find out. 

What is intumescent paint?

Intumescent paints are specially designed paints which are applied to a structure’s surfaces to help shield it from fire damage. This not only gives anyone inside valuable extra time to escape but will also help protect the structural integrity of the building, reducing its chance of collapse and damaging the surrounding structures and people. 

Intumescent paints are made from clever chemicals that, when exposed to high temperatures, rapidly expand up to 100 times their original thickness. This expansion results in the formation of a black insulating foam, often referred to as char, coating the treated material and acting as a shield from the flames. How long this protection continues depends on the type of Intumescent paint used but it typically lasts 30, 60, 90 or 120 minutes. 

Where can you apply intumescent paints?

Intumescent paints can be applied to most materials used in the structure of a building including: 

  • Steel – during a fire, it can take just minutes for steel to reach its temperature limit and begin to buckle. Intumescent paints help prevent this by protecting the steelwork from the high temperatures of the flames while firefighters tackle the blaze. 
  • Timber – wood is a highly combustible material so it’s crucial its treated with intumescent paint to help stop the spread of fire and allow precious extra minutes for anyone still inside the building to escape.  
  • Plaster - Intumescent paints can be applied to both plaster and plaster board for much the same reason as it is applied to timber. Intumescent paints can increase plaster’s resistance to fire from around 20 minutes to 60 minutes. 

Why do I need intumescent paint?

It is required by law to apply a layer of intumescent paint on all load bearing steel structures on all standard developments in commercial and industrial buildings in the UK. This is to help stop the spread of fire should one break out in a property, protecting the building and, more importantly, the people inside.  

Intumescent paint specialists 

As intumescent coating is such an important factor in a building’s safety, only specialists and proficient decorators should be involved in the application of intumescent paint. At Bell’s Decor, our team have years of experience applying this fire-resistant material and our Thermaguard paint is ordered on an individual, per-project basis. To give you added peace of mind, our paint is assessed and approved by the manufacturer themselves so you can be sure you’re getting the very best protection on the market. 


To learn more about our intumescent coating services, please don’t hesitate to get in touch with the friendly Bell’s Decor team today on 07852 654326 or by completing and sending our online contact form