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Damaged or missing intumescent and smoke seals on a fire door recorded during inspection

Defect Guide

Damaged or Missing Fire Door Seals

Fire door seals are critical components of a door set. If intumescent or smoke seals are missing, damaged, painted over, interrupted or incorrectly fitted, the door may not provide the expected level of smoke and fire resistance.

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Defect Overview

What Are Damaged or Missing Fire Door Seals?

Intumescent seals are designed to expand in heat, while smoke seals help restrict smoke movement. Seals should normally be continuous, correctly fitted, undamaged and compatible with the fire door set.

For property managers, landlords, facilities managers and responsible persons, seal condition should be reviewed alongside gaps, frame alignment and ironmongery, as these factors often affect how seals perform in use.

Risk & Impact

Why This Defect Matters

Seal defects can reduce the ability of a fire door set to restrict smoke movement and maintain fire separation performance.

  • Smoke may pass through unsealed gaps
  • Fire resistance may be reduced
  • Damaged seals may not activate or perform correctly
  • Painted, split or loose seals may need replacement
  • Missing sections can create weak points in the door set

Inspection Notes

How Inspectors Record Seal Defects

Where seal damage or missing sections are observed, inspection notes should identify the location and extent of the defect.

  • Door reference or location
  • Evidence photo of damaged or missing seals
  • Seal type and affected section
  • Visible interruptions around ironmongery
  • Related gap or frame observations
  • Suggested remedial priority where applicable

Inspection records visible seal condition at the time of visit. Replacement or further investigation should be carried out using suitable compatible seal products and competent installation.

Visible Indicators

Common Signs of Seal Problems

These are examples of visible indicators that may be recorded where observed during inspection.

  • Missing seal sections

    Gaps in the seal run may leave parts of the door edge unprotected.

  • Split, loose or damaged seals

    Physical damage can prevent seals from expanding or making continuous contact.

  • Painted-over intumescent strips

    Paint or coating over intumescent material may affect intended performance.

  • Smoke brushes that are flattened or worn

    Worn smoke seals may no longer restrict smoke movement effectively.

  • Interruptions around hinges, locks or ironmongery

    Breaks in seal continuity at hardware points can create weak areas.

  • Seals not contacting the door leaf or frame

    Poor engagement may indicate alignment issues or incorrect installation.

  • Incorrect or inconsistent seal type

    Unsuitable or mixed seal types may not match the intended door set specification.

Remedial Planning

What Should Be Done Next?

The next action depends on severity, building type and inspection findings. Seal defects should be addressed using suitable compatible products installed by competent contractors.

Recommended next steps may include:

  • Record the affected seal location
  • Photograph missing or damaged sections
  • Check related gaps, frame alignment and ironmongery
  • Arrange replacement using suitable compatible seals
  • Update inspection records after remedial works

Typical journey after a defect is recorded: inspection finding → defect noted in the fire door report → remedial works planned → re-inspection confirms the issue has been addressed where appropriate → door register or report evidence updated. See also inspection limitations and next steps after defects are found. For London bookings, see fire door inspections London.

Seeing a different visible issue? Use the Fire Door Defect Identifier to find the closest guidance and next steps.

FAQ

Common Questions About This Defect

Can damaged intumescent or smoke seals be replaced on site?
In many cases missing or damaged seals can be replaced with suitable compatible products fitted by a competent contractor. The correct seal type, size and position matter — informal substitutes or incomplete runs may not restore the intended performance. Suitability should be checked against the door-set and any available product evidence.
Why are painted-over seals a concern during inspection?
Paint can bridge, stiffen or mask intumescent and smoke seals so they may not expand or seal as intended in a fire. Inspectors often note painted, clogged or overcoated seals as a defect even when the seal is still physically present. Remedial work usually means carefully removing paint or replacing the affected seal sections.
Does a missing or discontinuous seal typically get recorded as a defect?
Gaps in the seal line, missing sections or clearly damaged seals are commonly recorded because continuous, correctly fitted seals support smoke and fire separation. How the finding is prioritised still depends on location, door type and overall condition. This is guidance for commercial UK inspections, not a guaranteed inspection outcome.
What happens after seal replacement — is a re-inspection needed?
After seal works, doors are often re-checked to confirm the seal is continuous, correctly seated and that related gaps and closing still look acceptable. Inspection records should then be updated so the remedial action is clear for the responsible person and future audits.

Related Defects

Related Fire Door Defects

Other common fire door inspection defects that may be recorded alongside this issue.

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