Why has my paint wrinkled?
Wrinkled paint is a wet-film fault, not a dried-film one: the surface skinned over while the paint underneath was still liquid. Three things cause that, and all of them are avoidable.
- Difficulty
- beginner
- Time
- 30 min
- Read
- 3 min
Short answer
The top of the film dried while the bottom stayed wet, so the skin slid and creased over the liquid beneath it. It happens when the coat is too thick, when it is recoated before the previous one has hardened through, or when strong sun or heat sets the surface fast. It cannot be fixed by painting over it — the wrinkles have to come off.
This is a different fault from crazing, which GuideHQ covers separately: crazing is a fine network of cracks in a film that has already dried, usually because of what is underneath it. Wrinkling is soft, ridged and looks like skin on custard, and it is entirely about how the film dried. Oil-based paints and varnishes wrinkle far more readily than emulsion, because they cure by reacting with air from the surface downwards.
Step by step
- Confirm it is wrinkling rather than crazing.Wrinkling gives soft parallel ridges, often worse on horizontal surfaces and in thick spots. Crazing gives a fine crack pattern in a hard film. Press a wrinkle gently with a fingernail; if it is still soft underneath, it is wrinkling.
- Stop and let it harden right through before touching it.A wrinkled film can stay soft underneath for days or longer. Sanding it while it is soft clogs the abrasive instantly and drags the paint into ridges. Wait until it is hard, even if that is a week.
- Remove the wrinkled film rather than burying it.Scrape or sand the wrinkles off back to a sound, level surface. Another coat over wrinkles only produces a thicker wrinkled surface, because the ridges telegraph straight through.
- Work out which of the three causes applied.Thick application: were you loading the brush heavily, or working a vertical surface where it gathered at the bottom? Premature recoat: did you go back over it the same day? Heat: was it in direct sun, or above a radiator that came on?
- Apply oil-based coatings in thin coats, and lay them off.Two thin coats cure properly and look better than one thick one. Spread the paint out, then finish with light strokes in one direction with an almost-dry brush to even the film.
- Respect the recoat time on the tin, not the touch-dry time.Touch dry means the surface has skinned. Recoat time means the film beneath has hardened enough to take another coat. These can be many hours apart, and the gap is exactly where wrinkling happens.
- Keep the work out of direct sun and off hot surfaces.Follow the shade round a building rather than painting the sunny face. Sun on wet oil-based paint sets the surface long before the body of the film.
Tips
- Wrinkling on a windowsill or a stair tread is usually gravity plus thickness: paint gathered in the flat area and skinned over.
- If the tin has been open a long time and is thickening, it will go on heavier than you intend and is more likely to wrinkle.
Common mistakes
- Sanding wrinkles while the paint is still soft. — The abrasive clogs and rolls the soft paint rather than cutting it, and you end up with a worse surface than you started with.
- Applying a heavy coat to get coverage in one go. — Coverage comes from two thin coats. A heavy coat is the most common single cause of wrinkling.
Questions people ask
How long should I wait before sanding it back?
Until it is genuinely hard, which can be several days for a thick oil-based film in cool conditions. Test in an inconspicuous spot: if the abrasive clogs, it is not ready.
Will a hardener or extra coat fix it?
No. Nothing applied on top removes a ridge. The wrinkled film has to be taken off and the surface made level again.