Gloss Paint Still Tacky Or Turning Yellow

What's happening?

These are two separate faults that both show up on woodwork. Gloss that stays tacky has not cured: oil-based paint dries by reacting with oxygen, and that reaction stalls in a cold or unventilated room, on a coat applied too thickly, or over a surface still carrying grease, polish or an incompatible earlier coating. Yellowing is different and is a known characteristic of oil-based white gloss: the binder ambers over time, and it does it fastest in darkness and behind closed doors, which is why the inside face of a cupboard, the back of a door and skirtings behind furniture yellow first while the same paint in a bright hallway stays whiter for longer.

What usually causes it?

• Applied too thickly, so the surface skins while the body of the film stays soft underneath
• Painting in a cold or unventilated room, below the minimum temperature on the tin
• Grease, wax polish, silicone or handling marks left on the timber before painting
• Recoating before the previous coat had cured, trapping soft paint under a skin
• Oil-based white gloss ambering in low light: normal behaviour for the binder, not a defect in application
• An incompatible primer or undercoat beneath the topcoat
• High humidity while the coat was drying, common in a bathroom or a newly plastered room

Is it dangerous?

No, though tacky paint on a handrail, a windowsill or a door edge picks up dust and hands and never recovers a good finish. Where you are stripping old paintwork to start again, treat anything decorated before the 1990s as possibly containing lead and avoid dry sanding or burning off.

Can I fix it myself?

Give it air and warmth first: open the window, get the room up to a normal temperature and leave it, since a slow cure often completes over several days. If it is still tacky after that, the coat has to come off; there is no coat you can put over soft paint that will fix it. For yellowing, a water-based satin or gloss will hold its whiteness far better than oil-based, though it needs the surface degreased, abraded and primed for adhesion before it goes on.

When should you call a painter and decorator?

Call a painter and decorator when the paint will not cure after a warm ventilated week, when it has to be stripped from a run of doors or a staircase, when the timber is old and may carry lead paint, or when you want white woodwork that stays white and need the right system specified. Getting a durable finish on doors and skirtings is preparation more than application, and it is the part that decides how long it lasts.

What will the painter and decorator actually do?

• Identify whether the fault is an uncured film, contamination beneath it, or normal ambering of an oil-based white
• Strip uncured or contaminated coatings back, using wet methods where lead paint is possible
• Degrease, abrade and dust off the timber, spot-priming knots that would otherwise bleed
• Prime and undercoat in a compatible system, respecting the recoat times on the data sheet
• Apply the topcoat in thin, well laid-off coats in a warm ventilated room

Who fixes this

• Woodwork and door painting

Questions people ask

Sources & References

1. Dulux Trade Paint Expert: Interior and exterior FAQs (application temperature and humidity)
2. Dulux: Common paint problems and how to fix them
3. Painting and Decorating Association