A safe, well maintained fire door could save a life, but it is only when it is tested that the consequences of poor installation are known. A 30 minute fire door may only provide five or ten minutes protection if fitted incorrectly.

Our manufacturer, JELD-WEN, works with the British Woodworking Foundation to improve standards and produce market leading, stylish fire doors to suit all types of properties.

Key considerations before installation

Internal fire doors are engineered for safety, protecting escape routes and preventing the spread of fire. There are four key considerations when choosing and installing a suitable product:

Certification and compatibility

Labels found on the edge of UK fire doors identify the manufacturer’s name, its unique traceability code and its rating – typically, they offer 30 or 60 minutes resistance against smoke and flames and will carry an FD30 or FD60 rating.

Make sure all ironmongery is also fixed firmly and CE marked, so you can be certain it will perform against fire and can be traced. Also ensure all hardware, frames, linings, casings, intumescent strips and smoke seals are compatible.


If you are using a door closer, it needs to be CE marked and compatible with your fire door so it latches from any position. In the event of a fire, the intumescent seal will only work effectively if the door is closed firmly, ensuring no smoke can leak through the gaps


Never trim the top edge of the door, as this holds vital safety information. If you need to make size adjustments, always check the instructions first as the allowance can vary.

Cutting holes for glazing or air transfer grilles, reducing the door size more than specified tolerances or removing safety markings will negate your certification. Building regulations are very strict and any small changes to the door or ironmongery may significantly affect its fire rating.


Non-combustible sealant must be used to fill any gaps between the doorframe and the wall, to prevent smoke penetration, whilst the space around the door itself must be no more than 3mm at the top and sides and 10mm at the bottom.

Intumescent strips fitted into the frame or door edges lie dormant in everyday use, but expand rapidly when exposed to extreme heat, creating a barrier against fire. Certain seals protect against smoke as well. Sometimes intumescent pads also are used behind the hinges and wrapped around locks and latches, but this depends on the fire door’s certification.

Slim fit fire doors

Until now, meeting fire regulations has been time consuming and complicated, however, JELD-WEN has introduced a 35mm slim door to simplify the process.

Combining safety and style, the 35mm internal door is 9mm narrower than traditional fire doors, allowing it to be used with most existing frames. It has a 30 minute rating and is certified by the BWF-CERTFIRE scheme.

Oak, moulded and veneer 35mm fire doors are available in a variety of styles and finishes. View our range of fire doors for more information.

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