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How to Upgrade The Fire Resistance Of Doors

Ever wondered how to upgrade a normal door into a fire door? Fire safety is something you should always be thinking about. Everything from internal walls and ceilings, exterior cladding, structural steel to interior doors should be considered. Avoiding fire safety measures, and the maintenance that comes along with them can result in serious accidents, fines and building regulation violations.

If you are updating or beginning a new job, doors are often an area requiring attention and many authorities will request normal doors be replaced with fire doors. Installing fire doors or upgrading your current doors can help to reduce the risk in the event of a fire. It gives fire fighters more time to access any burning areas, helps to prevent the spread of fire and crucially helps keep important means of escape clear.

Most modern, normal internal doors cannot be upgraded to achieve 30 or 60 minutes Fire Resistance due to them having a hollow core, being very thin or lightweight and liable to warping shortly after installation. Doors meeting such a description cannot be upgraded and should be replaced with a new Fire Door where one is required.

Reading on your mobile? You can shop the upgrade options here.



Whilst we recommend the installation of custom built fire doors there can be reasons not to do so. Some properties may fall under strict planning regulations and/or are listed preventing removal or substantial change to be made to interior doors, others may have unusually large or small doors that require fire protection, in these instances the products and systems discussed below may offer a solution to help satisfy the relevant authorities involved in your project by helping to increase the fire resistance of the timber elements of a door.

Our recommendation is that both sides of the door are always protected, intumescent strips are fitted and your authority is consulted for advice on any other necessary requirements such as ironmongery, signage, glazing, etc.

A written specification should be obtained from our Technical Department for your project prior to use to ensure the proposed system will be suitable. Contact us by phone on 0113 2455450 or email [email protected], products will NOT be sold without this.

We also recommend all product data sheets, system information and any relevant test data is read, understood and forwarded to your authority for approval/comment. Information is available to download from the ‘DATASHEETS’ tab on each product page but we also suggest you speak to our Technical Department to ensure you have the most current versions and ALL relevant documentation relating to your project as information is being updated regularly due to new testing, product developments, legislation changes, etc.

Remember, intumescent paints and varnishes are just one element of protection and DO NOT create a ‘fire door’. Intumescent materials and hardware MUST also be used to ensure your doors meet the required standards of your authority.

Painted Doors

Thermoguard’s Timbercoat Door Upgrade System is an intumescent paint system available as a convenient pack containing the required basecoat and topcoat to protect 2 doors in a white or coloured Eggshell or Gloss finish. Thermoguard UK will issue a Fire Certificate for Authority approved projects following completion.

As doors vary so greatly and the great majority are unsuitable for upgrading it is neither meaningful or realistic to carry out an official NAMAS / UKAS Fire Door Fire Test. Thermoguard Timbercoat’s uniquely effective formula resulted in the UK’s only successful official UKAS / NAMAS Fire Test Laboratory Fire Resistance Test to 60 minutes on softwood with timber lost to charring restricted to 7-10mm at 60 minutes… further details HERE.

Certain systems such as Envirograf’s Door Upgrade Paint System allow you to over paint their system with certain conventional decorative paints to ensure continuity of colour scheme throughout the building. The doors often don’t need to be stripped before application (preparation will still be required however) and as with most products you can also request a Certificate of Supply, signed by the applicator which can be shown to your local authority if requested for verification.

Varnished Doors

If you don’t want to interrupt the natural beauty of the wood on your timber doors, on bare or previously varnished/stained doors you can use a varnish to increase the fire resistance. Envirograf’s Door Upgrade Varnish System works in a similar way to their coloured paint system, by increasing the fire resistance of the timber areas of the door.


Envirograf have tested their Intumescent Coating and Intumescent Card/Veneer a number of times on different door types. Copies of these fire test reports are freely available upon request and some are readily available to download from our website. Envirograf also offer a range of products to complement their coatings such as fire & smoke seals, self-closing hinges, locks and hinge paper, glazing channels, glazing bead systems, glazing strips, ventilation grilles, and more.

A clear varnish with these properties can again help to reduce hazards created by fire, such as smoke, which can be just as dangerous as a fire. By using a fire door varnish and associated hardware, you can transform and upgrade your doors at the same time. You have the choice of different finishes, depending on the look and feel of your surroundings, so you don’t need to compromise when it comes to decoration.

Check doors and frames for any gaps that may allow the fire to pass through. Gaps may be present if a door hasn’t been installed correctly or is old, which will disrupt the effectiveness of your fire door paint or varnish if not dealt with.

Additionally, contact your relevant authority / Building Control Officers to check which doors they require protecting and seeking their approval for your proposed products and course of action prior to purchase and use of these systems.


As standards vary widely throughout the UK from property to property and region to region, it is important to check your doors have been installed correctly, and meet the minimum requirements of the product you wish to use, a fire door paint or varnish may be suitable for your project but not all doors are suitable and many need to be replaced.

*This article has been updated to reflect the new range of upgrade kits for extending the fire resistance of solid wood doors – 17/10/17


  1. A very interesting post to read. Thanks a lot for sharing this. Good Work.Keep it Up.

  2. A very interesting article! This blog will surely give the right insight and steps on how to start exactly in turning normal doors into fire doors. Indeed, nothing is more important is the safety of our family member. Thanks for sharing!

  3. Hello I am trying to find a way to preserve two doors built in the 1920s that need to be fireproofed according to Canadian standards. They appear to be a lighter wood – perhaps fir. They do have windows which would be replaced with fire rated glass. I would like to know if your paint product would be applicable. Can I send a picture?

    Stephen Milne

    • Hi Stephen,

      I’m afraid we don’t currently supply materials outside of the UK, you would need a supplier that is familiar with Canadian standards.

  4. Christine Fallon


    We have to ensure that some of the doors to flats in a converted listed building are fireproofed. Most residents are concerned with the aesthetic of the building so do not want the doors to be replaced given the buildings conservation status may not be acceptable. Could you let me know whether the paint and system would conform to current Fire safety compliance regulations? Also, can our painter and decorator carry out the works or do we need to employ a specialist.

  5. Hi, I live in a 1930’s terraced house and we have recently completed a loft conversion. We need to change or paint our first floor doors to ensure they have 30 minutes of fire resistance. Is it possible to keep our existing doors and paint them or do we need to swap them for fire doors? Many thanks.

    • Hi Jen,

      Thank you for your enquiry, please provide our technical team at [email protected] with an image of the door(s) (if possible) and as much information as possible for the below points;

      • Level of Fire Protection required? (i.e. 30min, 60min, etc.)
      • Style of door? (i.e. panelled, ledge & brace, etc.)
      • Solid or hollow core? – (please note we cannot provide anything to upgrade hollow doors)
      • Door size? (height and width)
      • Door thickness? (include thickness at thinnest point (i.e. panel))
      • Number of doors to do?
      • Clear or coloured finish required?
      • Bare or previously painted?
  6. Hi , I am based in Limerick , Ireland. Can this paint system be used here to gain a fire rating of 30 minutes. Two of the doors are hand made pine approx 2″ thick with solid panels. If so do you have a recomended distributor here, thanks

    • Thank you for your enquiry, please provide us with an image of the door(s) (if possible) and as much information as possible for the below points;

      – Level of Fire Protection required? (i.e. 30min, 60min, etc.)
      – Style of door? (i.e. panelled, ledge & brace, etc.)
      – Solid or hollow core? – (please note we cannot provide anything to upgrade hollow doors)
      – Door size? (height and width)
      – Door thickness? (include thickness at thinnest point (i.e. panel))
      – Number of doors to do?
      – Clear or coloured finish required?
      – Bare or previously painted?

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