Should You Repair or Replace a Lath and Plaster Ceiling?

Repairing a lath and plaster ceiling preserves the character and sound insulation of an older home, but replacing it is sometimes the only safe option if the plaster has pulled away from the timber. A standard ceiling replacement costs between £400 and £1,000, but expect to pay more to safely remove old laths or to patch with traditional lime.

What lath and plaster is

Builders in older properties constructed ceilings by fixing thin strips of timber across the structural floor joists with narrow gaps between them. They then applied multiple layers of wet lime plaster over this wooden base.

As the plaster was pushed onto the ceiling, it squeezed through the gaps between the laths and slumped slightly over the top of the wood. When the plaster set, these hooks of plaster, known as nibs or keys, locked the ceiling onto the laths. The nibs do most of the work of holding the heavy plaster up.

According to a best practice guide on historic lath and plaster ceilings published by FIS, the trade body for the finishes and interiors sector, common failures include delaminating from the laths, cracking, sagging and the risk of collapse. The guide recommends that repairs are sympathetic, robust and where possible reversible.

Why old ceilings crack and sag

Over decades, the constant tiny movements of a house take a toll on the plaster. Walking on the floorboards above, moving heavy furniture or nearby road traffic all cause vibrations that slowly weaken the mechanical bond holding the ceiling together.

Water leaks from a bathroom or a damaged roof are another common cause of failure. Lime plaster can cope with small amounts of moisture, but a heavy leak can saturate the plaster, add weight and break its grip on the laths. The laths themselves can also rot or warp if they stay wet for too long.

When the nibs break, the plaster delaminates. This means it separates from the laths and rests its entire weight on the surrounding plaster. Hairline cracks are normal in older properties, but wider cracks that appear suddenly can mean the bond has failed.

Warning signs that need prompt attention

You can often tell if a ceiling is failing by looking closely across the surface with a bright torch. Fine, spiderweb cracks are common and do not always mean the ceiling is dangerous. However, you should look out for signs that the plaster has lost its grip:

• A sagging or bulging section pointing to delamination.
• Wider cracks that appear suddenly overnight.

Do not press, prod or tap a suspect ceiling to test it, because a loose section can come down. If you spot sagging, bulging or loose sections, you need prompt professional inspection. A heavy lime ceiling can cause serious injury and damage if it falls. You should keep the area below clear until a skilled plasterer has assessed the structure.

When a repair is the better choice

Fixing an isolated problem is often the best approach if the damage is localised. If only a small section has failed due to a plumbing leak, a plasterer with heritage experience can remove the loose material and patch the hole using a traditional lime mix.

The Society for the Protection of Ancient Buildings advises that old plasterwork is worth conserving wherever possible. They recommend retaining as much existing lime plaster as you can, and note that any replacement should normally be the same material. Lime plaster can offer better internal comfort and sound insulation than modern substitutes.

You will need a specialist for this work. Standard plasterers who work only with modern materials may suggest taking the ceiling down or covering it up because they do not work with traditional lime.

Overboarding as a middle option

If the original surface is beyond a simple patch but the underlying structure is sound, tradespeople often suggest a compromise. Overboarding involves fixing new plasterboard directly under the old ceiling and applying a thin finishing coat, known as a skim, over the top.

Overboarding avoids the immense dust and disruption of tearing down an old ceiling. The plasterer must find the structural joists and use screws long enough to pass through the new plasterboard, the old plaster and the laths, anchoring firmly into the solid timber above.

This method adds weight to your ceiling structure, so the joists must be strong enough to carry it. It will also lower your ceiling height slightly. If your room has an original decorative cornice, the new layer of plasterboard will eat into its depth and can spoil its proportions.

When replacement makes sense

Sometimes an old ceiling is too far gone to save. If the plaster has delaminated across the whole room, or a large section has already collapsed, full removal and replacement is usually the safest route.

Taking down a lath and plaster ceiling means hacking off the failed plaster and pulling down the timber laths. The plasterer will then fix new plasterboard to the exposed joists and skim it to a smooth finish. This process is known in the trade as board and skim.

Replacing the ceiling gives you a perfectly flat surface and allows you to inspect the structural joists for rot or woodworm. It also makes it easy for an electrician to run new wiring for lighting before the new plasterboard goes up.

Dust, asbestos and other safety points

Work on historic ceilings carries specific health and safety risks. The dust created by tearing down lath and plaster will find its way into every room if the work area is not properly sealed. You must remove all furniture and soft furnishings from the room before work starts.

Many older ceilings were covered with textured coatings, such as Artex, to hide cracks and uneven surfaces. The Health and Safety Executive states that textured coatings on ceilings may contain asbestos in any building built or refurbished before 2000.

Work on these coatings does not normally need a licensed contractor, but it must be done by people trained to work safely with asbestos. You should not sand, scrape or drill suspect coatings yourself, and you must tell tradespeople about them before work starts. Dry sanding or scraping old Artex can release asbestos fibres into the air, which is why the work is left to trained people.

If a ceiling covered with a textured coating collapses, cleaning up the debris is classed as work with asbestos that needs trained people, so homeowners should not tackle it themselves. Any trader who carries waste away from your home must be a registered waste carrier, and you can check the public register to confirm their status.

What it is likely to cost

Plasterers price work after visiting your home to inspect the room. They will look at the state of the background, check the ceiling height and assess the preparation needed, such as dealing with old Artex or moving heavy items. A written quote for ceiling work should clearly list several key elements so you know exactly what you are paying for:

• The preparation work needed before plastering starts.
• Whether sealing painted surfaces is included.
• The cost of scaffolding or access equipment for high ceilings.
• Floor protection and the final clearing of the room.
• The removal and legal disposal of all waste.

The table below outlines guide prices for standard plasterboard ceiling work. These figures are typical published prices for 2026, and your local quotes will differ based on the condition of your home and the access required.

These are guide figures for standard plasterboard and skimming work. They do not cover taking down lath and plaster or repairing it with lime, so you should expect those jobs to cost more. Repairing with traditional lime is priced case by case, as it requires specialist skills and multiple visits to allow the coats to dry.

Labour rates also vary by location. A plasterer normally costs between £150 and £200 per day, but tradespeople in London and the South East will charge more. When you ask for a price, check whether the quote includes VAT and materials.

How long the work and drying take

The time needed to finish your room depends entirely on the method you choose. A standard full ceiling replacement using modern plasterboard takes one to two days for a typical room. Overboarding is slightly faster because the plasterer does not have to spend hours pulling down the old laths and bagging up the heavy debris.

If you opt for a traditional lime repair, the physical work might only take a few days, but the waiting time between coats extends the project. The plasterer must leave each layer of lime to cure before applying the next, meaning they will need to make several visits spaced out over time.

Drying times also dictate when you can finish the room. A modern gypsum skim on plasterboard will usually dry to a pale pink colour in around a week, provided the room is well ventilated. You can read more about whether you need skim plastering or a full replaster to understand the different modern finishes.

Lime plaster dries slowly because it cures by absorbing carbon dioxide from the room rather than simply losing water. Specialist plasters such as lime can need up to a month before painting. Rushing this process with heaters can make the lime dry too fast and crack, so you must be prepared for a longer wait before you can decorate.

Listed buildings and period homes

Owners of listed buildings face strict rules on internal repairs. You cannot simply tear down an original lath and plaster ceiling without permission, even if it is badly cracked or sagging.

The Planning Portal says that listed building consent is needed for any significant works, whether internal or external. You should speak to your local council's conservation officer before a ceiling is removed or overboarded.

Conservation officers generally want to preserve the historic fabric of the building. They will usually advise repairing original lime plaster where possible and replacing like for like if a section has failed completely. Unauthorised work on a listed building is a criminal offence, so you must secure the right consents before the plasterer starts work.

If your home is not listed but sits in a conservation area, a National Park, an Area of Outstanding Natural Beauty or the Broads, you generally do not need planning permission for internal ceiling work, but you should check with your council if you are unsure.

Finding a plasterer with lime experience

Plastering is not a licensed trade, meaning there is no legal register of approved tradespeople like the one for gas engineers. Finding someone who truly understands traditional lime requires careful checking of their past work and speaking to previous customers.

Many modern plasterers only know how to work with modern gypsum plaster. Applying gypsum or cement over old lime walls or ceilings is a common mistake that traps moisture and causes the new plaster to fail. You need a tradesperson who can explain the difference between a modern skim and a traditional lime repair, and who understands how to check the finish before you pay.

When looking for a tradesperson, do not rely on a CSCS card as proof of quality for domestic work. These cards are for people working on construction sites. Instead, look for membership of FIS, the trade body for the finishes and interiors sector, or the government-endorsed TrustMark quality scheme.

Under the Consumer Rights Act 2015, all work must be done with reasonable care and skill. If a plasterer skims over loose, damp or unsealed painted surfaces and the new coat cracks or peels, you can ask for it to be put right or seek a partial or full refund.

You should always avoid cash-only deals with nothing in writing. Citizens Advice suggests getting three written quotes, signing a written contract, paying a deposit of no more than 25 per cent and paying by card. They also note that you might be able to cancel within 14 days of agreeing a contract. If you end up in a dispute with a trader, Citizens Advice can explain your options.

Common questions

Can you skim over lath and plaster?

You can apply a thin finishing skim over an old ceiling only if the existing plaster is completely sound and firmly attached to the laths. If the old plaster is loose, damp or crumbling, the new skim coat will simply pull away and crack. A plasterer must assess the strength of the nibs before adding more weight to the ceiling.

How do you fix cracks in a plaster ceiling?

Fine cracks can often be filled and painted during normal decoration. For wider cracks in a lath and plaster ceiling, a specialist will clean out the loose debris and patch the gap with a matching lime mixture. You should never ignore cracks that appear alongside sagging or bulging, as these suggest the plaster is coming away from the laths.

Does lime plaster take longer to dry?

Traditional lime takes much longer to cure than modern gypsum plaster. It dries slowly by absorbing carbon dioxide from the air, and you must leave it to cure fully before decorating. You can read more about how long plaster takes to dry to understand the timeline for your project.

What is lath and plaster made of?

The ceiling consists of narrow timber strips nailed to the structural joists, covered with several coats of wet plaster. In older homes, this plaster was made from lime, sand and animal hair, which provided strength and flexibility. The mixture was pushed through the gaps in the timber to form a mechanical grip.

Next steps to take

Taking a methodical approach will help you secure the right repair without overpaying.

• Look across the ceiling from floor level with a torch to identify any bulging or sagging areas.
• Keep the space beneath clear if you suspect the plaster has delaminated from the timber laths.
• Speak to your local conservation officer first if your property is a listed building.
• Ask tradespeople if they have specific experience working with traditional lime plaster.
• Ensure any quotes are fixed prices in writing, not rough estimates.
• Check that the written quote includes preparation, ceiling access, waste removal and floor protection.
• Tell the tradesperson if you suspect the ceiling has an old textured coating that might contain asbestos.
• Confirm that the person taking away your waste is a registered waste carrier.

Finding a skilled tradesperson is the best way to understand whether your ceiling needs a simple patch, a layer of plasterboard or a complete replacement. You can read reviews and find a plasterer near you to arrange an inspection and get a detailed written quote.