Fire doors only work when they close properly, latch properly and seal properly. The frustrating bit is that many common failures are small and easy to miss until an inspection or an incident forces action.

This guide is built around real user intent: “What should I check and what counts as a problem?” It’s also aligned with the checks described in the UK government’s fire door guidance.

If you’re responsible for a building and need surveys or remedials, these are the most relevant service pages:

• Commercial Fire Door Installations & Remedials

• Contact

Quick answer: the 60-second fire door check

Do these three checks in order. If any fail, log it and book remedials.

1. Close test
   Open the door fully then let it go. It should close fully into the frame and latch. Then repeat from about 15 degrees. This is the simple test recommended in the UK government fire door guidance.

2. Gap glance
   Look along the sides and top. If the gap looks uneven, visibly wide, or you can see daylight, it needs a proper gap check.

3. Seal scan
   Check the perimeter seals are present, continuous and not damaged or painted over. Government guidance specifically flags damaged or painted-over seals as an issue.

What counts as a fail right away

These are the “do not ignore” issues:

• The door does not close into the frame or does not latch

• The door is wedged open or the closer has been disabled

• Large gaps around the door edge

• Missing, damaged or painted intumescent strips or smoke seals

• Hinges have missing screws or the door is dragging badly

• Glazing is cracked, loose or looks like it has been altered

These are all consistent with the simple checks set out in the government guidance and London Fire Brigade advice for property managers.

How to check gaps properly

This is the check that catches the most failures.

What gap size should you be looking for

UK government fire door guidance states the industry standard is no more than 4mm around the door to frame gap, except at the bottom where it should be as small as practical without snagging.

You will also see best practice references to 2–4mm at the head and vertical edges, with threshold limits depending on the door’s smoke control needs and specification.

The simple way to measure

• Use a gap tester card or gauge rather than guessing by eye. Government guidance notes these are available and useful.

• Check: hinge side, latch side, top edge

• If it varies a lot from top to bottom, that usually points to wear, poor alignment, hinge issues or a door that has dropped

If you want a quick printable checklist style approach, the government guidance is the most reliable reference point for what to look for.

How to check seals

What you’re checking

You’re looking for intumescent strips (fire) and smoke seals (smoke). They may be combined.

What good looks like

• Present around the perimeter where specified

• Continuous, not cut short around hardware

• Not torn, crushed or missing sections

• Not painted over

UK government guidance explicitly calls out seals that are damaged, not making contact, or painted over.
London Fire Brigade also highlights combined seals and the need to ensure components like letter plates are suitable.

If seals are missing or damaged, do not DIY swap parts unless you are matching the door’s certified specification. This is where remedial works matter.

How to test the self-closer

Self-closers are a common point of failure because doors get heavy use and people get tempted to “make it easier”.

The closer test

• Open the door fully and release, it should close fully and latch

• Open the door about 15 degrees and release, it should still close fully and latch

This exact approach is recommended in the government guidance.

What a failing closer looks like

• Door stops short of the frame

• Door closes but does not latch

• Door slams aggressively (can cause damage and tampering)

• Door only closes from a wide open position, not from a small angle

Hinges, latches and glazing

Hinges and screws

• No missing screws

• No looseness or movement in the hinge leaf

• No heavy rubbing that suggests the door has dropped

Government guidance flags obvious defects like missing or loose screws in hinges and ironmongery.

Latches and handles

• The latch should engage easily

• The handle should return properly

• No stiffness that prevents full closure

Glazing and vision panels

• No cracks

• No loose beading

• No signs the glazing has been changed

Government guidance includes checking the condition of fire-resisting glazing systems and associated panels.

Common defects we see

These show up again and again:

• Gaps that have grown beyond tolerance due to wear or door drop

• Seals painted over during decorating

• Closers adjusted badly so doors do not latch

• Hinges with loose screws or missing fixings

• Door held open without a compliant hold-open arrangement

When to book a survey or remedial works

Book professional help if:

• The door fails the close test

• Gap sizes are out of tolerance

• Seals are missing, damaged or painted over

• The door leaf is damaged, warped or modified

• You need documentation for compliance or handover

For businesses, blocks, offices, public buildings and managed sites, remedial works and sign-off are exactly what this service is for: Commercial Fire Door Installations & Remedials.

If you’re also tightening up broader compliance on refurb projects, this article pairs well: 7 Compliance Essentials for UK Commercial Refurbishments in 2025.

Fire door FAQs

How often should fire doors be checked?

For multi-occupied residential buildings over 11m in England, the Fire Safety (England) Regulations 2022 introduced requirements including quarterly checks of fire doors in common parts and annual checks of flat entrance doors on a best endeavours basis.
Even outside that category, responsible persons still have duties under fire safety law to keep doors effective as part of general fire precautions.

What is the most common reason fire doors fail?

Doors not closing and latching properly, excessive gaps or damaged seals. The government guidance focuses heavily on exactly these points because they stop doors doing their job.

Can I fix a fire door problem myself?

Basic reporting and simple checks, yes. Technical changes, parts swaps, seal replacement, closer replacement, glazing changes, no. The fact sheet on the regulations makes clear the routine check is to spot obvious issues, with more detailed checks or specialist involvement needed when faults are found.

What gap is too big around a fire door?

Government guidance states the industry standard is no more than 4mm around the frame gap, except the bottom which should be as small as practical without snagging.

Need a compliant fix with documentation?

If you want the doors checked properly and brought up to spec, use:

• Commercial Fire Door Installations & Remedials

• Contact