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What do cracks in plaster mean, and when should you worry?

Most cracks in plaster are surface cracks from drying, settling or joints in plasterboard, and a plasterer or decorator can fill or skim them. Cracks that keep widening, run diagonally from door and window corners or appear in the wall outside too need a builder or structural engineer to look first.

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By the QuoteZila editorial team. Editorial policy.

What kinds of cracks appear in plaster?

Cracks in plaster are common, and most are not a sign of anything serious. The shape, direction and behaviour of a crack tell you more than its length.

Common types:

  • Fine crazing. A web of tiny cracks across new plaster, often from drying too quickly.
  • Straight lines along board joints. Cracks along the edges of plasterboard sheets, often on ceilings, where joints were not taped or have moved.
  • Corner cracks where a wall meets a ceiling or another wall. These often open and close a little through the year.
  • Short cracks at door and window corners. A small crack from the corner of a frame is common as a house settles.
  • Diagonal or stepped cracks that widen as they go, especially from the corners of openings. These are the ones to take seriously.

QuoteZila is starting in Cheshire, with Crewe, Nantwich and Sandbach among the first towns, and anyone in the UK can post a job. This page helps you decide who to call first.

Which cracks need more than a plasterer?

Ask a builder or a structural engineer to look before any plaster repair if:

  • The crack keeps getting wider, or has reopened after being filled.
  • It runs diagonally across the wall, or steps through the brickwork outside.
  • You can see a matching crack on the outside wall.
  • Doors or windows near it have started to stick or no longer close properly.
  • The floor or ceiling near it has started to slope or sag.
  • The crack appeared after nearby work, such as a wall being removed or a large tree cut down.

Those signs can point to movement in the structure, and the plaster is only showing it. If structural work is needed, building control may be involved. GOV.UK explains when you need building regulations approval.

GOV.UK: find your local council for building control. QuoteZila is not affiliated with this organisation.

How do you keep an eye on a crack?

If you are unsure, watch the crack for a few weeks before deciding:

  • Mark the ends with a fine pencil line and write the date next to each mark.
  • Photograph it with a ruler or a coin beside it, from the same spot each time.
  • Check it again every week or two, and after a spell of very wet or very dry weather.

A crack that stays the same is less worrying than one that grows. Keep the notes and photos, as they help a builder or engineer understand what is happening.

How are plaster cracks repaired?

The repair depends on the cause:

  • Fine surface cracks can be raked out slightly, filled with a flexible filler and painted.
  • Board joint cracks usually need the joint taping and filling properly, or the ceiling reskimming.
  • Lots of cracks across a wall may be better dealt with by a fresh skim coat over the whole surface.
  • Old plaster that is cracked and loose may need cutting out and replastering, which is closer to a blown plaster repair. See blown plaster.

Repair work makes dust. HSE says regularly breathing construction dust can cause diseases including asthma and silicosis [S2]. Old textured coatings need care too: HSE lists them among the places asbestos can be found inside a house [S1]. You can read HSE's diagrams of where asbestos can occur.

What should you ask before work starts?

Whether you start with a plasterer or a builder, ask:

  • What do you think caused the crack, and is it still moving?
  • Will a filler hold, or does the area need taping, skimming or replastering?
  • Do you need a structural engineer's view first?
  • Who will redecorate afterwards, and is that in the price?

Citizens Advice suggests getting written quotes from at least three traders, and says a quote is a fixed price while an estimate is a rough guess [S3].

Jobs you might post

These are examples, not taken from real job posts.

  • "Long straight cracks along the board joints on a bedroom ceiling. Please quote to tape, fill and repaint, or reskim if needed."
  • "Diagonal crack above the back door that has got wider over the summer. Looking for a builder to assess before any plastering."
  • "Several fine cracks across a newly plastered wall. Please quote to fill and decorate."

Get quotes for cracked plaster

Describe where the cracks are, how long they have been there, whether they are growing and what is on the wall now, with photos if you can. Up to five matched local businesses can send you a quote [QZ2]. QuoteZila is free for customers and local businesses [QZ1].

Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.

Posting a job is not open yet

See our plasterers page, builders page and painters and decorators page. For ceilings, see what changes the cost of a ceiling repair.

Questions about cracked plaster

Are hairline cracks in plaster normal?

Fine cracks are common in new plaster as it dries, in older plaster as a house moves with the seasons, and along joints in plasterboard. If they stay fine and do not grow, they are usually cosmetic and can be filled and painted over.

When is a crack in plaster a sign of something worse?

Be wary of cracks that keep widening, that run diagonally from the corners of doors and windows, that you can see on the outside wall as well, or that come with doors and windows that start to stick. Ask a builder or structural engineer to look before anyone repairs the plaster.

Can I fill cracked plaster myself?

Small surface cracks in modern plaster can be raked out, filled and sanded. Keep dust down, and be careful with old textured finishes. HSE says asbestos can be found in any home built or refurbished before 2000, including textured coatings such as Artex. Have those checked before you sand or scrape them.

Why do ceiling cracks keep coming back?

A crack that reopens after filling is usually moving. Common reasons are plasterboard joints that were never taped, a ceiling that flexes when people walk above it, or old lath and plaster losing its grip. Filling alone will not hold, so ask a plasterer about taping, reskimming or reboarding.

Does QuoteZila check the businesses who quote?

No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.

This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.

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Sources

  1. QZ1: QuoteZila product fact. QuoteZila home and FAQ copy.
  2. QZ2: QuoteZila product fact. QuoteZila FAQ How does getting quotes work.
  3. S1: Diagrams showing where asbestos can occur in buildings, HSE. Accessed 2026-11-01. https://www.hse.gov.uk/asbestos/diagrams.htm
  4. S2: Construction dust, HSE. Accessed 2026-11-01. https://www.hse.gov.uk/construction/healthrisks/hazardous-substances/construction-dust.htm
  5. S3: Before you get work done on your home, Citizens Advice. Accessed 2026-11-01. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/