Fire door seals help the doorset perform as intended, but damage, gaps, poor adhesion, paint contamination or incorrect compression can affect their operation. Intumescent seals are designed to expand when exposed to heat; smoke seals help limit smoke leakage when correctly specified and fitted. Check the seal type and position against the doorset evidence and manufacturer instructions. Look for missing or loose sections, cuts, crushing, paint, debris, inconsistent contact and damage at corners or joints. Do not assume a replacement seal is suitable because it looks similar: confirm the required product, dimensions and compatibility before changing it. Record the location and condition of any defect, and refer uncertain or significant issues to a competent fire-door professional. Explore the related fire door seal articles below for specific fault-finding guidance.