Paint Cracking On Walls, Ceilings Or Corners
- How urgent
- Low risk
- Who fixes it
- A painter and decorator
What's happening?
Dulux names two causes of cracked paint film. Mud cracking comes from a thick, heavy, unthinned coat, especially on a textured or embossed surface such as blown vinyl wallpaper or pebbledash and especially when brushed on, and it can also happen when matt paint goes over silk without the sheen being removed. Cracks that follow a joint or corner are different. Dulux says excessive movement of the surface underneath, at joints for example, stresses the paint film and cracks it, and the cracks then let in moisture and lead to flaking. Rawlins Paints adds that hairline cracks in ceilings usually sit at plasterboard joints, from poor taping and jointing or slight movement of the building. Cracking at ceiling edges can be different materials moving at different rates, which is often not structurally significant.
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What usually causes it?
- A thick, heavy, unthinned coat of paint, especially on a textured surface
- Matt paint applied over silk without removing the sheen
- Movement at plasterboard joints, corners or ceiling edges, cracking the film
- Poor taping and jointing of plasterboard
- Moisture or steam in bathrooms and kitchens attacking a stressed film
- A building that is settling or a crack in the plaster underneath
Is it dangerous?
Not in itself. Cracks that are wide, stepped or diagonal, or that keep growing, can point to structural movement, and are a builder's question rather than a decorator's. Rawlins says unsupported loads and foundation movement can cause wider cracks at ceiling edges and in nearby walls. Older paint can contain lead, which HSE says is present in older buildings, and textured coatings in older homes may contain asbestos, so do not dry-sand or scrape either: leave them undisturbed and ask for advice first.
Can I fix it myself?
Look at the pattern. A web of fine cracks across the surface is paint film. A line along a joint, a corner or the ceiling edge is movement. Do not paint over active cracks: open them slightly, fill with flexible filler or decorators' caulk, and let it dry. Use flexible filler where there is slight movement, such as door frames and corners, and stop painting and scrape back loose paint if the ceiling starts to peel. If cracks are wide, stepped, growing or show brown staining, stop and get the cause checked.
When should you call a painter and decorator?
Call a painter and decorator if the cracking is across the paint film, or the surface needs stripping and preparing. Call a plasterer or a builder if the cracks follow joints and keep returning, or are wide or stepped. Tell them when it appeared and whether it has moved.
What will the painter and decorator actually do?
- Work out whether the cracking is in the paint film or in the plaster and joints beneath
- Strip or scrape back loose and cracked paint to a sound edge
- Open and fill cracks with flexible filler or decorators' caulk
- Prime filled areas so the paint does not soak in unevenly
- Repaint in thin coats, using the right sheen for the surface
Who fixes this
- Painting preparation
- Ceiling painting
Questions people ask
Why is my paint cracking?
Why is paint cracking in the corners of my room?
Why is the paint cracking along my ceiling?
Can I just paint over cracked paint?
Sources & References
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