How-to · 4 min read · Updated 6 November 2026
Cracks and nail pops in plasterboard: causes and proper fixes
Normal settling or a real problem?
| What you see | Likely cause |
|---|---|
| Fine hairline cracks at corners in the first year | Normal drying and settlement |
| Small round bumps over screws | Timber shrinking, screws not fully seated |
| Straight cracks along board edges | Joints not taped or boards moving |
| Diagonal cracks from door or window corners | Movement, or board joints placed at the corners |
| Crack where wall meets ceiling | Seasonal movement of joists or roof timbers |
| Wide or growing cracks with sticking doors | Possible structural movement, get advice |
Why nail pops happen
Timber studs and joists are often installed with some moisture in them. As they dry in a heated house, they shrink slightly and the screw or nail heads are pushed proud of the board surface. Nails pop more than screws, which is one reason plasterboard screws are now standard. Screws driven too shallow, or into the edge of a joist, also tend to pop.
Pops often show up in the first winter after building work, when the heating dries the timber most quickly. They tend to appear in lines along a stud or joist. Fixing them all at once, after the house has been through a full heating season, avoids repeated visits.
Fixing a popped screw
- Press the board firmly against the stud or joist
- Drive a new plasterboard screw about 40 to 50 mm from the popped one
- Drive the original screw back in, or remove it if it will not hold
- Set each screw head just below the surface without tearing the paper
- Fill with joint filler in two or three thin coats, sanding lightly between
- Prime the patch before painting so it does not show through
Fixing a cracked joint properly
Filling a joint crack with a flexible filler and painting over it rarely lasts if the joint was never taped. The proper repair is to rake or cut out the loose material, check the boards either side are firmly fixed, add screws if they move, apply joint tape bedded in jointing compound, then build up and feather out the filler in thin coats.
Where the crack is at the junction of wall and ceiling and opens and closes with the seasons, a flexible decorator's caulk or a small coving can be more reliable than rigid filler.
Filled areas absorb paint differently from the surrounding wall, which can leave a dull patch. Seal the repair with a primer or a diluted coat of emulsion, lightly sand when dry, then paint the whole wall or ceiling rather than just the patch, so the sheen matches.
Reducing cracks on new work
- Use dry, stable timber and allow it to acclimatise before boarding
- Stagger board joints and avoid joints lining up with door and window corners
- Follow the board manufacturer's fixing centres
- Tape every joint and internal corner
- Leave the building to dry out gradually, and avoid blasting the heating straight after finishing
- Allow a few months before final decoration of new extensions where possible
Where new board meets old plaster, such as in an extension or where a wall has been removed, the junction is a natural weak point because the two parts move differently. Taping across the junction, or forming a neat shadow gap or movement joint, gives a more reliable result than relying on filler alone.
When to get advice
Cracks that are wider than a few millimetres, that keep growing, that run diagonally through masonry outside, or that come with doors and windows sticking can indicate structural movement such as subsidence, failing lintels or overloaded joists. These need checking by a surveyor or structural engineer before any cosmetic repair.
Ceilings that crack or sag
Ceilings crack for the same reasons as walls, but gravity adds an extra factor. A sagging plasterboard ceiling usually means fixings have failed, the joists are too widely spaced for the board thickness, the board got wet, or something heavy has been stored in the loft above.
- Check the loft for leaks, water tanks and heavy storage directly above the problem
- Look for long cracks running parallel to the joists, which often follow board edges
- Press gently on the ceiling to see if the board moves
- Do not stand under a ceiling that is visibly bulging or wet
A board that has been soaked by a leak loses strength and usually needs replacing rather than refixing. Dry, sound boards that have dropped slightly can often be screwed back up to the joists with extra fixings, then retaped and filled.
Frequently asked questions
Is it normal for new plasterboard to crack?
Some fine cracking in the first year is common, especially at corners and where walls meet ceilings, as timber dries and the building settles. These are cosmetic and easy to fill once things have stabilised. Long straight cracks along joints, cracks that come back repeatedly or boards that move when pressed suggest a fixing or taping problem.
Should I wait before repairing cracks in a new extension?
If the cracks are fine and cosmetic, it is usually worth waiting until the building has been through a heating season, often six to twelve months, before final repairs and decoration. Repairing too early means cracks may reappear. Anything wide, growing or accompanied by sticking doors should be looked at straight away.
Can I just use flexible filler on plasterboard cracks?
Flexible filler can hide small cracks for a while, but it does not fix the cause. If a joint was never taped or the boards are loose, the crack usually returns. For a lasting repair, secure the boards, tape the joint and refill with jointing compound. Flexible caulk is useful at wall and ceiling junctions where seasonal movement is expected.
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