Can You Paint a Fire Door? Yes — But Not the Seals

What's safe and what isn't

• Safe: ordinary paint or varnish on the door leaf and frame faces, in reasonable coats
• Not safe: paint on intumescent strips/smoke seals — dried paint prevents the strip expanding and the brush seal sealing; mask them or remove-and-refit
• Not safe: painting over the certification label or plug — identity lost at the next inspection
• Watch gaps: repeated repaints add millimetres; a door at 2mm tolerance can end up binding or out of spec
• Don't fill or pierce: no new letterboxes, cat flaps, vision panels, planing, or trimming without fire-rated methods — each voids the door's tested configuration
• Ironmongery swaps (handles, closers, hinges) must be like-for-like fire-rated, with intumescent pads where the original had them

Redecorating a block? Brief the decorators

Most painted-up seals we find were done by professional decorators on communal redecoration cycles — strips painted into the groove on every riser and corridor door in the building in one efficient, destructive fortnight. The fix is one paragraph in the decoration spec: mask all intumescent and smoke seals, do not paint labels, report damaged seals rather than painting over them. Remediating painted seals afterwards (cutting out and replacing strip throughout a block) costs vastly more than the masking tape would have.

Repair or replace after bad painting?

Painted strips are replaceable: the old strip is cut out and new intumescent (and brush seal where fitted) installed in the groove — a standard remedial we do door-by-door, far cheaper than door replacement. Painted-over labels are tougher: gentle solvent recovery sometimes works; otherwise the door joins the 'cannot evidence' list and the inspection report says so. A leaf swollen with decades of gloss that no longer meets gap tolerances may need easing or, at the extreme, replacing — judged at inspection.