Intumescent paint for wood

Applied with intumescent paint for wood

Prevent fire with intumescent paint for wood

As the Great Fire of London proved, the greatest danger to wood is fire. Yet despite the warnings of history, wood is still a very common building material. As a result, fire safety products continue getting better and better and now there is even a fire retardant paint to protect your home: intumescent paint for wood.

Applying intumescent paint for wood can be a smart move to protect your family and yourself from dangerous situations. Intumescent coatings for timber are suitable for wooden interior and exterior surfaces.

The way intumescent paint protects wood from fire is simple; when exposed to extreme heat, the paint will expand and form a foam which then solidifies, creating an insulating coating which is also a very poor heat conductor. This solid foam layer protects the wood underneath in the event of fire.

Benefits of intumescent paint for wood

While intumescent coating for wood does not prevent structures from catching fire, it will drastically reduce the speed of burning. Once fire begins, an intumescent coating means wooden structures last longer and burn slower, giving people valuable time to escape.

Intumescent coating upgrades wooden surfaces to withstand fire for 30 or 60 minutes.

intumescent paint for timber

Fire to treated wood vs. bare wood

Wood as a material is not only sensitive to fire, but also weathering, UV exposure, and humidity. Consequently, most intumescent paint systems also have other protective properties specially developed for wooden surfaces. These include:

  • Fire protection
  • Protecting against UV radiation.
  • Insulating furniture, doors and flooring safely
  • Suitable for untreated wood
  • Applicable on already painted surfaces (though you will need to apply a primer)
  • Fire door upgrades

Clear intumescent paint for wood

There are multiple different options for intumescent paint on wood. The coating is suitable for softwoods, hardwoods, even chipboard and MDF, in both interior and exterior settings (there is also intumescent paint for non-wood surfaces, such as steel and concrete). It can also be used as a wood sealer and then painted over; or as a top coat over pre-painted or pre-stained wood.

The intumescent coating for wood is usually a clear finish which retains the natural looks of the substrate.

Clear intumescent paint for wood exists as lacquer-like hard finish, preserving wood treatment and clear intumescent varnish for wood. It is one of the most popular fire preventing coatings due to the fact that it does not affect the appearance of the wood, but still provides appropriate protection from fire.

Man spraying intumescent paint on wood

Applying intumescent varnish on wood walls.

Applying clear intumescent paint

To reach a proper level of coverage from your intumescent coating, two different products are usually needed (although it is possible to use a single product). For bare wood, two coats of an intumescent timber paint followed by a coat of a fire retardant varnish would be optimal.  The combination of the two should increase the protection, applying two different protective methods. The final varnish will also define the final appearance of the coating, and comes in a range of finishes.

Intumescent varnish for wood

Most intumescent wood coatings are also suitable for upgrading ordinary doors into fire doors. Usually the doors are treated with a clear intumescent varnish for wood, in order to retain the looks of the door.

Before applying intumescent varnish for doors, you should check whether the doors are suitable for becoming fire doors. The requirements are:

  • Solid doors, not hollow
  • Minimum door thickness of 35 mm

If your door is made of sunken panels, the panel thickness and wood type matter. Softwood panels must have a minimum thickness of 16 mm whereas for hardwood panels 12 mm is enough. Are the panels thinner? No problem; you can buy a veneer kit to increase the thickness, so long as it is no thinner than 9mm.

Intumescent paint for wood products & prices in the UK

The following table gives an indication on the intumescent wood paint prices in the UK. The price is given including VAT.

Brand Product type Price (RRP) Packaging
Bollom Intulac Ultra Varnish Basecoat An intumescent varnish coating for interior wood surfaces.  £187.60  5L
Bollom Intulac Ultra Topcoat A decorative varnish topcoat for interior wood. Applied with Bollom Intulac Ultra Basecoat for class 0 protection.  £43.66  500ml
Thermoguard Fire Varnish Basecoat First coat of a 2 coat system for internal or external wood.  £118.80  for 20m²
Thermoguard Fire Varnish Overcoat (Exterior) Final coat of a 2 coat system for external wood.  £60.00  for 20m²
Thermoguard Timbercoat An intumescent paint system for bare and painted wood and timber derivative surfaces.  £90.00  5Kg
Envirograf Fire Door Paint A coating pack for upgrading wood doors to up to 30 minute fire resistance.  £260.99 20m² kit

Intumescent paint for wood UK Standards

In the UK, the body that sets the Standards in industry and trade is call the British Standard Institute. Through rigorous testing, they establish the required performance and fire resistance of elements of a structure, including materials such as fireproof paints. These are known as the British Standards (BS), and include standards for intumescent coatings. BS 476 relates to fire tests, and divides intumescent coatings into two classes: 1, and 0.

Ability to resist fire

The fire prevention properties of paint and coatings are measured by dividing the products into those which can stop and prevent the spread of fire for 30 minutes and those for 60 minutes.

BS class 1

Class 1 is normally required for walls and ceilings, areas with moderate risk of fire. The paint must not allow the spread of flame to be greater than 165mm in 10 minutes.

BS class 0

Class 0 requirements are for high risk areas, corridors, staircases and escape routes. They include class 1, but add an extra requirements known as the ‘Fire Propogation Index’ which measures how much the paint contributes to the fire. The coating must have a very low ability to catch fire and burn.

Certification for your intumescent paint for wood

No matter whether you are getting the job done by a professional or doing it yourself, you should get the work certified. Many coating manufacturers and painters provide product and application certificates. These may come in handy with insurance policies or if you ever need to claim insurance.

If you want everything done absolutely right, we advice you to contact a certified intumescent paint contractor; or let us find one for you!

We are happy to connect you with the most suitable intumescent paint and contractor for your project. All you need to do is send us a message!

Intumescent paint for wood contractors throughout the UK

Area Company Address
England Fire Lining Systems Ltd 54 Hutton Close, Crowther Industrial Est , Washington , NE38 0AH
England, London area SIV Fire Protection Ltd Waterfront Business Centre, 57A North Woolwich Road,  London E16 2AA
England, London area Adept Contracts Ltd Unit C, Atcost Road, IG11 0EQ, Barking, Essex
Scotland A1 Sprayers 56-58 Jane Street, Edinburgh, EH6 5HG
Scotland Holemasters Scotland Ltd 114 Main Street, Chapelhall, Airdrie, Lanarkshire, ML6 8SB
Wales Sharpfibre Unit D1, Britannia Centre for Business , Pengam, Blackwood, NP12 3SP
Wales Taylor Engineering UK Ltd Unit 7 / 8, Curran Road,Cardiff, CF10 5NE

In case you wish to gain any additional information, detailed product and service prices, application possibilities or advice on certification and standards, our coating experts are happy to help you! 


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