Overview
If you’re dealing with repeat fire door defects, it’s usually the same few culprits: fit, gaps, and seals.
- the door doesn’t close and latch
- gaps are inconsistent (or obviously too large)
- smoke or intumescent seals are damaged, painted over, missing, or poorly fitted
Even without getting into tolerances, you can do a decent first-pass triage by focusing on performance and obvious defects. If there’s any doubt, get it checked properly.
Why gaps and seals matter
Fire doors are a system (leaf, frame, hinges, closer, latch/lock, seals, glazing, and hardware). Gaps and seals matter because they affect whether the door:
- closes fully (no binding or dragging)
- latches reliably (so it stays shut)
- limits smoke spread in early stages of a fire (often the biggest day-to-day life risk)
- behaves consistently when used hundreds of times a week
If gaps are excessive or inconsistent, or seals are missing/damaged, you can end up with a door that looks “fine” but doesn’t behave like a fire door in use.
What to check (in plain English)
- Does it self-close and latch? A door that needs “help” to latch is often the real issue.
- Are gaps consistent? Look for obvious tapering gaps, rubbing points, or daylight.
- Are the seals present and continuous? Missing sections or gaps at corners are common.
- Has decorating compromised the seals? Paint build-up can stop seals working as intended.
- Is the threshold detail appropriate? Threshold issues can cause doors to drag or stay ajar.
Quick on-site checks that catch most issues
- Let-go test: open the door to a normal use position and let it go. It should close and latch without you pushing it.
- Latching check: confirm the latch engages, and the door cannot be pulled open without operating the handle.
- Visual gap scan: look around the leaf perimeter for obvious inconsistency.
- Seal continuity: check seals are continuous and seated correctly (no missing corners or ripped sections).
- Damage/warping: look for impact damage, swelling, or a leaf that doesn’t sit square in the frame.
Common causes of gap and seal problems
- Hinges loosening over time (or incorrect hinge type)
- Closers out of adjustment or damaged
- Frames moving (fixings loose, swelling/shrinkage, impact damage)
- Poor repairs (e.g., seal carriers missing, wrong seals fitted)
- Warped or damaged leaves
Common defect patterns we see in the real world
- Daylight at the meeting edge (double doors) or at the head/hinge side (leaf/frame movement).
- Seals painted over during decorating, becoming brittle, stuck, or partially torn.
- Seal carriers missing (or replaced with the wrong profile) after minor repairs.
- Threshold drag after new flooring, carpet tiles, door bars, or swelling.
- “Bouncing” off the latch because the closer latching action isn’t strong enough or alignment is off.
What to do when you find a problem
Prioritise defects that affect closing and latching
Treat these as priority issues because they affect day-to-day performance:
- the door does not self-close
- the door does not latch reliably
- seals are missing or badly damaged
- gaps are obviously inconsistent or you can see daylight
Escalate when repair might compromise certification
Some doors can be repaired safely; others need a more controlled approach. If the door is third-party certified or part of a regulated door set, avoid “creative fixes” and get competent advice before:
- planing/trimming the leaf
- changing seals to an unknown profile
- swapping ironmongery without understanding compatibility
What good records look like (so issues stop repeating)
The best programmes are easy to re-check.
Capture:
- door ID and precise location
- what failed (e.g. “won’t latch”, “seal missing hinge side”, “dragging at threshold”)
- why it matters (performance impact)
- action taken (adjust / repair / replace / monitor)
- close-out evidence (photos + date)
A simple defect triage table
| Defect pattern | Why it matters | Typical next action |
|---|---|---|
| Won’t latch reliably | Door can be pulled open; inconsistent performance | Check closer + latch alignment; escalate if repeated |
| Daylight / large gaps | Indicates poor fit, movement, or damage | Assess against doorset requirements; avoid guessing |
| Missing/damaged seals | Reduced smoke control and auditable defects | Replace with suitable, compatible seals |
| Threshold dragging | Stops closing/latching; encourages wedging | Check flooring changes, alignment, and closer setup |
FAQs
What gap is “acceptable”?
There are tolerances in guidance and door set certification, but in practice you should avoid guessing. Use it as an escalation trigger: if gaps are clearly inconsistent/large, or the door won’t latch, have it assessed against the door set requirements.
Can we just plane the door to stop it rubbing?
Sometimes remedial work is possible, but planing/trimming can affect certification if it’s not controlled. Treat it as a competent repair decision, not a quick maintenance tweak.
Can we just replace the seals?
Sometimes. But only if the rest of the assembly is sound and the replacement is appropriate. A seal swap won’t fix a door that won’t latch or a leaf that’s warped.
Is a door still “okay” if it closes but doesn’t latch?
No. If the latch isn’t engaging reliably, the door can be pulled open easily and won’t behave consistently under normal use.
Related pages
Note
This article is general information. Always align inspection outcomes and remedials to the building’s fire risk assessment and competent guidance.