Fireproof Paint

Treated with fireproof paint and untreated wood

Fireproof paint for work and at home

Coatings are in a crucial position when it comes to fire prevention and increasing safety in houses, commercial buildings, and institutes such as schools and hospitals. Unfortunately, completely fireproof paint does not exist; however, there are several types of fire coatings which slow down the burning process and protect the structures from catching fire. Fire protection paint contributes to safety by:

  • Increasing evacuation time
  • Holding off structural collapse
  • Protecting surrounding buildings
  • Increasing the safety of firefighters

In the UK, fire coatings are required in some commercial and residential buildings, though in houses these are not yet obligatory. But with fire coatings becoming more and more prevalent and easy to apply, it is always better to be safe than sorry.

Types of fireproof paint

Advances in fireproof coatings have increased the safety of firemen

Advances in fireproof coatings have increased the safety of firemen

There are three main types of fireproof coating:

  • Cementitious coating – including cement and gypsum sprays, this is a foam-like insulator, and offers the longest lasting protection (four hours)
  • Intumescent paint – coatings which swell up when exposed to heat extremes, producing a low density solid (char) which prevents heat from reaching the substrate
  • Flame damping coating – releases a flame-damping gas when it becomes too hot, acting as a fire retardant

All of these coatings fight fire by protecting the underlying material from its damaging effects.

Using a char-forming undercoat with a flame-damping topcoat combines the protective qualities of both coatings, giving maximum fire protection.

Fireproof paints may be applied over some but not all other coating types. Always check before you apply!

Types of fireproof paint protection for steel

Applying fire protection paint for metal

Applying fire protection paint for metal

Of all the metals, steel is the most commonly used in construction. Fire paint for steel comes in both char-forming (intumescent paint for steel) and flame-damping coating varieties. It is possible to reach up to 120 minutes extended fire protection as the fire paint reacts to high temperatures (above 200 degrees)  by expanding up to 50 times thicker than its original thickness.

While metals do not catch fire easily, the extreme heat damages them; steel will lose its structural integrity and load-bearing capabilities. It is important, therefore, to keep steel structures protected against fire.

Fireproof paints for steel are available as water-based and solvent-based options. They are easy and quick to apply, suitable for steel beams, interiors, and exteriors, and are available in a variety of colours and finishes.

Fireproof paint application for steel

  1. Thin film fire paint for steel beams – These consist of three layers: primer, basecoat and sealer. The basecoat is the one which reacts with fire. These coatings are often applied in buildings where 30, 60, or 90 minutes fire resistance is required. Thin film coating applications can take place on site or off site, with a solvent-based paint for hot and dry environments. Decorative layers can be applied.
  2. Off site fireproofing paint for steel: – Applying fire paint for steel beams and other structures off site allows quicker construction and the opportunity for better quality control. Additionally, off site applications improve site safety, reduce site disruption and result in cleaner sites. This is a common application method for non-aesthetic end uses, and has had great success in the UK.
  3. Thick film fire rated paint for steel: – Thick film intumescent coatings are usually epoxies which dry much thicker than thin film coatings. These coatings are typically applied for particularly severe circumstances where thin film would not work. Thick film coatings are most common in exterior steel structures such as skyscrapers. Thick film coatings are suitable for on site and off site applications.

Types of fireproof paint for wood

applying intumescent paint for wood

Applying fireproof paint for wood

While wood catches fire more easily than metal, it retains its ability to bear heavy loads. The speed at which wood burns means fireproofing wood is vital for the safety of homes and buildings. There are intumescent paints for wood, however, most often the fire protection coatings are flame damping varnishes and oils.

In case of fire, a wooden structure treated with the right coating bears the heat for longer and does not catch fire.

Fire protection paints can be applied to softwoods, hardwoods, even chipboard and MDF, on interior and exterior surfaces. It comes in water- and solvent-based systems, and also serves to preserve the wood and increase durability in general. The best results can be achieved by applying fire protection paint to unsealed wood so the coating can best bond with the substrate.

Making doors fireproof

In some buildings, doors must also be fireproof. The required fire rating is defined by the location of the door; some doors require 30 minutes fire resistance whereas others only need 20 minutes fire resistance.

There are two basic requirements for fire doors:

  • Minimum door thickness is 35 mm
  • Doors must be solid, not hollow

If you wish to treat a door with sunken panels, bear in mind that the panel thickness matters! Hardwood (such as oak) must be at least 12 mm thick and softwood (for example pine) should have a minimum thickness of 16 mm.  You can also purchase a special veneer kit to increase the thickness. However, the original door panels must be at least 9 mm to qualify for veneering.

When applying fire paint for doors to upgrade standard doors to 30–minute fire doors, you must include them as part of an overall fire risk prevention programme. The door itself can be coated with fireproof paint, but you will need other fireproof measures, such as coating the locks and hinges. Most suppliers of fire paint for doors also offer complete door upgrade kits which include everything you need for upgrading you door.

Fireproof paint products in the UK

Here are some of the wide range of fire protection coatings available in the UK. The prices are a rough guide, and include VAT.

Brand Product Price Packaging
Zero Flame Fireproof paint for internal surfaces; suitable for almost any substrate £116 5 L
Jotun  Steelmaster; fireproof paint for metal  £156.62  18.5 L
 Bollom Intulac Ultra; varnish for fireproofing wood  £187,60  5 L
 Thermoguard  Timbercoat & Smoke and flame retardant Dualcoat, wood fire protection paint system  £153.60  5 Kg + 20 sq m basecoat
 3M  Scotchkote; fire protection paint for wood, fibre boards and composite surfaces  £83.62  5 L

Fireproof paint and UK building regulations

Fire safety is controlled by the UK building regulations which provide guidelines for structures and building materials regarding fire resistance. The British standard for fire safety is BS 476. Fire protection paint is suitable for preventing burning on external surfaces (walls and roofs), internal linings (walls and ceilings) and internal structures. The building regulations also define how long a structure or surface should last after the fire breaks. For example the basement storey in houses should be 30 minutes fireproof and the upper storeys 30 or 60 minutes depending on the height of the top floor above ground (up to 5 metres and more than 5 metres).

Fire certification

Fire certification is a proof of fire safety of the building. It includes the proof of purchase, batch numbers of the fireproofing paint products, site details and usage data. Most of the coating applicators provide documents (certificate of supply) to attach to the proof. The fire certification can be especially handy when it comes to insurance policies and actual damage.


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