How to Repair a Plaster Ceiling?

Understanding Plaster Ceilings

Before trying to repair a plaster ceiling, it’s good to know what kind of ceiling you’re dealing with. In London homes, especially older ones, ceilings usually fall into two categories:

• Lath and Plaster: If your home was built before the 1950s, chances are you’ve got this. It’s made by nailing thin wooden strips (called laths) to the ceiling joists, then adding layers of plaster. The plaster squeezes through the gaps in the laths to form ‘keys’ that hold it in place.
• Plasterboard (Drywall): This is the newer method. Big sheets of plasterboard are screwed directly onto the joists, and the seams are taped and covered with a skim coat of plaster for that smooth finish.

Knowing what type of ceiling you have makes a big difference when it’s time for a professional plastering service. Lath and plaster tend to crack and sag as they age, while plasterboard is sturdier but can take a hit from water damage or impacts.

Common Causes of Plaster Ceiling Damage

Ceiling damage doesn’t happen out of nowhere. It always has a cause. Figuring out what’s behind it is key to stopping the problem from happening again and starting the process to repair a plaster ceiling. Here are some common reasons:

• Building Settling: Over time, buildings naturally shift and settle. This can put stress on plaster and lead to small cracks, like those tiny hairline fractures you might have noticed.
• Temperature and Humidity: Changes in moisture and temperature make materials expand and contract, which often causes cracks. This is especially common in kitchens and bathrooms where humidity levels fluctuate.
• Poor Craftsmanship: If the plasterboard wasn’t taped properly or the plaster mix wasn’t strong enough, you might end up with cracks or sagging ceilings down the line.
• Ageing Materials: Plaster doesn’t last forever. Over the years, it can become brittle and lose its grip, leading to sagging, bulging, or cracks and typical signs of an ageing ceiling.
• Water Damage: Leaks from plumbing or roofs can soak into plaster, leaving behind stains, sagging issues, or worse, potential collapse. Bathroom ceilings are especially vulnerable because of humidity or hidden leaks.

Understanding what’s causing the damage is half the battle in looking for ways to repair a plaster ceiling!

Signs of Serious Structural Issues

Take a good look at the damage. Small cracks or peeling paint? You can probably fix those yourself. But if you’re dealing with deep cracks or sagging, it’s time to call in a pro. While most cracks are harmless, some can be a red flag. Look out for these warning signs:

• Big or Growing Cracks: If you spot a crack wider than 5mm or one that’s clearly getting longer, it’s time to call in a professional who knows how to repair a plaster ceiling.
• Clusters of Cracks: Seeing multiple cracks branching out from one spot? That could mean there’s a stress issue in that area.
• Cracks Near Walls, Doors, or Windows: Cracks where the ceiling meets the wall or around doors and windows might be a sign of structural movement.
• Uneven Floors and Sticking Doors: Noticing ceiling cracks along with sloping floors or doors that won’t open or close properly? Don’t wait. Get a structural engineer to take a look ASAP.

For a detailed guide, read our blog: Top Signs Your Walls Need Replastering.

How to Repair Cracked Plaster on a Ceiling? Step-by-Step Guide

How to Repair Small Cracks?

• Widen the Crack: It might seem counterintuitive, but you need to make the crack slightly larger. Use a utility knife to carve a 'V' shape along the ceiling cornice cracks. This removes loose debris and creates a key for the new filler to grip onto. Vacuum out any dust.
• Apply Tape: Covering the crack with self-adhesive mesh or fibreglass tape is the best way to fix crack in plaster ceilings. Press it down firmly.
• Apply Plaster Compound: Using a joint knife, apply a thin layer of plaster compound over the tape, pressing it firmly into the crack. Feather the edges outwards to blend with the surrounding ceiling.
• Sand Smooth: Allow the first coat to dry completely. If needed, apply a second, wider coat to create a seamless finish. Once fully dry, sand the area lightly with fine-grit sandpaper until it's perfectly smooth.
• Paint: Prime the repaired area and then paint it to match the rest of your ceiling.

How to Repair Large Cracks?

• Remove Loose Plaster: Start the process to repair a plaster ceiling with large crackes by carefully getting rid of any crumbling plaster until you reach a stable, solid edge.
• Apply Adhesive (Optional): If the edges are weak, you can inject some construction adhesive to help stabilise the old ceiling cracked plaster.
• Prime the Surface: Apply a bonding agent, like Plaster Weld, to make sure the new plaster sticks properly.
• Apply Base Coat: Fill in the damaged area with plaster, leaving it just a bit below the level of the surrounding ceiling.
• Apply Finish Coat: Smooth on the finish coat and use a trowel to level it with the rest of the ceiling.
• Texturise (If Needed): If your ceiling has texture, take the time to match it for a seamless look or call in a professional if it feels tricky!

How Do I Fix a Hole in a Plaster Ceiling?

• Cut out the damaged area: Grab a utility knife or pad saw and cut a clean square or rectangle around the hole. Aim to extend it to the nearest ceiling joists if you can. Remove all the damaged bits.
• Insert and secure the plasterboard: Cut a piece of plasterboard to fit snugly into the opening. If the hole isn’t near any joists, add small wooden supports (noggins) inside the ceiling to screw the patch onto. Once that’s done, secure the patch with plasterboard screws.
• Apply plaster compound: Use mesh tape to cover the joints around the patch. Then, apply a few thin layers of plaster compound over the tape and screws, making each layer a bit wider than the last for a smooth finish.
• Sand smooth: Let the final coat of ceiling repair plaster dry completely, then sand it down until it’s nice and smooth.
• Paint: Prime it, paint it, and watch the patch blend right in with the rest of the ceiling.

Discover more in our blog: Fixing Plaster Wall Cracks? Causes and Solutions.

How To Fix Sagging Plaster?

• Access from Above (If Possible): If accessible from above, remove loose debris and pour a bonding plaster over laths to secure the sagging ceiling.
• Apply Adhesive: Drill small holes into the sagging area and inject construction adhesive to reattach the ceiling cracked plaster securely to the laths.
• Support the Ceiling: After applying adhesive, push the sagging section back into position and prop it up securely until the adhesive fully cures.

Essential Tools for Plaster Ceiling Repair

Safety first before starting to repair a plaster ceiling! Throw on some goggles and a dust mask to protect yourself. Don’t forget to cover your furniture and floors with plastic sheets and tape them down to keep all that dust and debris under control. Here are the tools that you need to do a proper ceiling plastering job.

• Utility Knife: Perfect for trimming edges or getting rid of damaged plaster when making repairs.
• Trowel and Plaster Hawk: Your go-to tools for holding and spreading plaster evenly over surfaces.
• Joint Knife/Putty Knife: Great for filling cracks and smoothing out smaller areas with ceiling repair plaster.
• Sandpaper or Sanding Block: Essential for creating a smooth, seamless surface before you start painting.
• Vacuum Cleaner with Brush Attachment: Keeps the dust and debris under control during sanding.
• Self-Adhesive Mesh Tape: A handy fix to strengthen repairs and stop cracks or joints from reopening.
• Primer (like Plaster Weld): Helps new plaster stick firmly to old surfaces with no peeling or slipping!

Preventing Future Plaster Ceiling Damage

Once you're done with the bathroom ceiling plaster repair, you'll want to keep it in great shape, right?

• Take a quick look at your ceilings now and then, especially in places like the kitchen and bathroom where moisture loves to hang out. Spotting damage early can save you a lot of trouble later.
• Make sure your home stays well-ventilated! Use extractor fans in the bathroom and kitchen to keep moisture from building up and messing with your ceilings.
• If you notice a water leak, don’t wait and tackle it right away. Fixing the problem fast can stop more serious and expensive damage.
• And it’s always a good idea to bring in the professionals, like Serviceteam, for regular checkups. They can catch small issues before they turn into big headaches, saving you time, money, and stress.

Cost Considerations To Repair a Plaster Ceiling

When it comes to tackling a repair, cost is usually one of the first things to think about. Prices can vary a lot depending on the size of the room, the type of plaster, and how easy it is to access.

• For a full replacement in an average-sized London room, you’re looking at anywhere between £500 and £2,000 or more.
• If you’re up for some DIY, the costs are pretty low- around £50 for filler, tape, and sandpaper should cover minor repairs.
• On the other hand, hiring a professional plasterer in London will cost you between £200 and £400+ for a day’s work. For bigger or more complex jobs, this can be a smart choice to ensure a quality finish.

Your Next Steps for a Perfect Ceiling

If you’re in London and need a hand, Serviceteam is here for you. Our awesome, vetted tradespeople are ready 24/7 to take care of whatever you need like plastering, plumbing, electrics, you name it. Just give us a shout, and we’ll make sure your ceiling is good as new, keeping your home safe and looking great for years to come.

Take a moment to read our blog: Transform Your Home with a Professional Plastering Service.

Frequently Asked Questions

It usually costs between £300 and £1,000, depending on the size, materials, and labour. If you’re in London, it might cost a bit more because of higher demand. To get the best deal, it’s always a good idea to get quotes from a few different contractors.

First, you’ll need to cut out the damaged section, fit a new piece, and secure it with screws. Then, apply some joint tape and filler, sand it smooth, and finish by repainting or re-plastering. If you’re in London or unsure about doing it yourself, getting a professional can save you time and stress.

For small holes, just clean the area, apply some patching plaster or filler, sand it smooth, and repaint. Bigger holes might need a plasterboard patch. If you’re in London, there are plenty of contractors who can handle it quickly and professionally.

It involves removing the old plaster, putting up new plasterboard, and applying a fresh coat of plaster. It’s not a DIY-friendly task, so it’s best to hire professionals. In London, most contractors include disposal of the old materials and finishing touches in their quotes.

Plasterers or general builders usually handle plaster ceiling repairs. If you’re in London, you’ll find lots of specialist plaster repair companies or local tradespeople who can help. Just make sure to check reviews and credentials before hiring to ensure quality work.