Plaster Repairs and Assessment Guide Scope of Works Survey & diagnose : tap‑test walls, use moisture meter, mark hollow/blown areas and hairline cracking. P...
Plaster repair in the UK typically costs £60–£300 for routine small repairs (cracks, holes, small patches) and £300–£1,000+ for larger areas with structural causes (damp, settlement, lath-and-plaster failure). The cheapest mistake is repeated cosmetic patching of cracks that have a structural cause — the cracks always come back.
Diagnosis matters more than treatment. A 30-minute professional assessment can tell you whether you have movement, damp, blown plaster, or simple shrinkage cracks — each needs different treatment.
Typical UK plaster repair costs
| Repair | Typical price |
|---|---|
| Small crack filling (per crack) | £40–£90 |
| Hole repair (per hole, up to 30 cm) | £70–£150 |
| Patch repair (per m²) | £50–£120 |
| Damaged corner repair | £60–£150 |
| Bay / damaged wall section repair | £200–£500 |
| Re-plaster damp-affected wall | £300–£800 |
| Plaster assessment (diagnostic visit) | £60–£120 |
| Lath and plaster repair (period homes) | £200–£600 per m² |
| Ceiling repair (after leak) | £200–£600 per ceiling |
| Full room re-plaster | £800–£2,500 |
Common plaster problems and what they mean
- Hairline cracks — usually shrinkage (new plaster drying) or seasonal movement. Cosmetic; often resolved by filling and repainting.
- Vertical cracks > 2 mm — possible structural movement. Worth investigating with a surveyor before cosmetic repair.
- Stair-step cracks (diagonal) — typically structural movement, often subsidence-related. Don't just patch; investigate cause.
- Bulging plaster — plaster has separated from the wall behind. Hack off and re-plaster.
- Crumbling plaster — usually damp damage; underlying moisture issue must be addressed first.
- Flaking surface — paint adhesion problem rather than plaster problem. Sand back, prime, repaint.
- Brown stains — water leaking from above. Track and fix the source before any plaster work.
- Damp patches — rising or penetrating damp. Specialist damp survey before plaster repair.
The assessment visit — why it's worth £60-£120
A diagnostic visit by an experienced plasterer or surveyor confirms:
- Whether the cause is structural, damp, or cosmetic.
- Whether you need a builder, surveyor, or damp specialist before plastering.
- Realistic scope of work needed (often less than you fear or more than you hoped).
- A written quote with proper measurements.
The £60-£120 is typically refunded against the eventual repair cost.
When to fix vs investigate further
- Repaint cracks recurring within 2-3 years — investigate. Recurring cracks usually mean structural cause that needs addressing.
- Damp patches — investigate first. Damp specialists £80-£200 for survey; can save thousands in misdirected plaster work.
- Brown stains — find and fix the leak source. Plaster repair only after the cause is dealt with.
- Cracks at corners only — usually settlement; cosmetic repair often sufficient.
- Multiple horizontal cracks at first-floor level — possible joist movement; have a structural look.
Things people often miss
- Most cracks are cosmetic — UK homes settle slightly seasonally; small cracks reappearing each year are almost always cosmetic. Don't panic over hairline cracks at corners or above doorways.
- Damp-cured plaster needs to dry — after damp treatment, plaster repair must wait until walls are properly dry. Premature plastering traps damp.
- Period homes need period materials — lath-and-plaster repair with modern gypsum plaster is wrong. Use lime-based plaster on lime-based walls; gypsum on gypsum-based walls.
- Mist coat after plastering — always 50-50 water-thinned paint as the first coat over fresh plaster. Otherwise paint peels.
- Plasterboard repair vs plaster repair — different materials, different tools. Most plasterers handle both, but ask about experience with the type of wall you have.
- Wall thickness check — adding plaster to walls where pictures, sockets, or radiators are fixed may need them re-fixed in different positions.
Frequently asked questions
Why do my walls keep cracking?
Three common causes: seasonal movement (UK homes flex slightly), structural settlement (gradually slowing), or moisture (cracks at damp lines). Recurring cracks need investigation; one-off cracks are usually cosmetic.
How big a crack should I worry about?
Hairline (under 1 mm): cosmetic, fill and repaint. 1-3 mm: monitor over a year. Over 3 mm or stair-stepped: investigate; may need structural attention. Over 6 mm with displacement: get a structural engineer to assess.
Can I patch a hole myself?
Small holes (under 5 cm): yes, ready-mixed filler £5-£15 from B&Q, sand smooth, paint over. Larger holes (5-30 cm): plaster patching kit £20-£60, more skill needed. Whole-wall repair: professional plasterer.
Why won't my paint stick to the new plaster?
Plaster wasn't fully dry when painted, OR mist coat was skipped. Solution: scrape off failing paint, allow plaster to dry fully (1-3 weeks), apply 50-50 water-thinned mist coat, then full-strength topcoats.
What's the difference between plastering and rendering?
Plastering is interior; rendering is exterior. Different materials (rendering uses cement or lime mortars designed for outside use; plastering uses gypsum). Different trades sometimes, though many tradespeople do both.
How long does plaster repair take?
Small patch: 1-2 hours plus drying. Bay or larger area: half-day to full day plus drying. Full room re-plaster: 2-3 days plus 1-2 weeks drying. Add waiting time for damp / structural fixes if needed.
Want a local pro to handle this? A plasterer with diagnostic experience can tell you when you need other trades (surveyor, damp specialist) before plaster work. £60-£120 for an assessment visit is typically refunded against the repair and saves money in the long run.
This guide was written with AI assistance and is intended for general information only. Prices are estimates based on UK averages and may vary by region. Always get at least three quotes and consult a qualified professional before starting any work.
