Top Notch Walls logo org
Request Free Quote

How To Fix Plaster Ceiling Cracks

15 June 2023

Have you noticed cracks in your walls and ceilings? Cracks in plaster ceilings can be a common problem in any home, regardless of its age. They not only compromise the aesthetic appeal of your ceilings but can also indicate underlying structural issues.

At Top Notch Walls, we know just how frustrating, worrying, and (potentially) costly it can be. But don't panic! In most cases, cracks in a plaster surface are superficial and can be easily fixed.

In this step-by-step guide, we will walk you through the process of repairing cracks to get your home looking perfect once again.

From assessing the damage to preparing the existing plaster and applying the necessary repairs, we will cover all the essential aspects to help you restore your ceiling to its former glory. We'll also cover some important points that you need to be aware of and throw in some helpful tips.

So let's dive in and learn how to fix those unsightly plaster ceiling cracks!

Assessing The Damage

Before you begin, it's crucial to assess the extent and nature of the cracks. This assessment will help you determine the underlying causes and choose the appropriate repair method. Here's how to do it:

  • Inspect the crack pattern. Examine the cracks and note their length, width, and direction. Look for any signs of movement or gaps between the plaster and the underlying structure. Is there bulging plaster anywhere? A sagging plaster ceiling usually means that something has caused it to break away from the substrate. Water leaks are probably the leading cause of this problem, but old plaster can simply fail due to its age. In these cases, it's likely that you'll need to replaster the entire area, although it may be possible to repair it if you're feeling brave!
  • Identify the cause. Common causes of plaster ceiling cracks include settling, exposure to moisture, temperature changes, or structural issues. Identifying the cause will help you address it to prevent future cracks.
  • Check for structural damage. Look for any signs of structural damage, such as sagging or movement in the ceiling. If you suspect significant structural issues, consult a professional before proceeding with repairs.

Our post "How To Fix Cracks In Plaster Walls" maybe interest you. You can check it out.

How To Fix Plaster Ceiling Cracks

Different Types Of Substrate

It's extremely important to establish what type of ceiling you have, as this could affect the method needed to fix it.

There are two basic types of ceilings in the UK, and these are:

  • Plaster and wood lath. Plaster and lath is a traditional method used from the 1700s until around the 1950s. Thin strips of timber are attached to the joists (or vertical posts if it's on a wall) with a gap of around 6mm between them. Lime plaster is then applied, using the spaces between the strips to help it to grip. Sagging plaster on this type of ceiling is usually the first sign that is failing and may collapse. If you have an old house that was built before the 1950s, your plaster walls and ceilings may need checking as they can fail due to their age.
  • Plasterboard/Drywall. These are large sheets of gypsum board sandwiched between tough paper. Almost all modern homes have these as they are cost-effective and speed up the construction process. As opposed to wet plastering, plasterboard only needs a skim coat of plaster over the top. From the 1970s onwards, Artex was widely used to give a textured look to ceilings, but this isn't as popular these days. Please see below for some information regarding Artex that you should take note of before starting any work on your ceiling.

Gathering The Required Tools & Materials

To fix plaster ceiling cracks effectively, you'll need the following tools and materials:

  • Safety equipment - Safety goggles, dust mask, and gloves to protect yourself during the repair process.
  • Tools - A utility knife, putty knife, wire brush, sandpaper, paintbrush, ladder, and a plaster mixing paddle.
  • Materials - Plaster of Paris or setting-type joint compound, fibreglass mesh tape, bonding primer, paint, and a dust sheet to protect the surrounding area.

Preparing The Surface

Properly preparing the damaged area is crucial to achieving a long-lasting and seamless repair, and this is how you go about it:

  • Clear the area - Move furniture and cover the floor and surrounding surfaces with a dust sheet to protect them from dust and debris.
  • Remove loose plaster - Use a utility knife or putty knife to scrape away any loose or damaged plaster around the cracks. Be gentle to avoid further damage to the sound plaster.
  • Clean the area - Use a brush to remove any loose particles and broken plaster and to create a clean surface. It's also a good idea to run a vacuum cleaner over the area. Wipe the area with a damp cloth to remove dust.
  • Apply primer - Use a bonding primer to seal the surface and ensure proper adhesion of the plaster. Follow the manufacturer's instructions for application and drying time.

Repairing Plaster Cracks

Now that everything is prepared, let's proceed with the actual repair process:

Widening The Cracks

For hairline cracks, if they're very fine, you may be able to simply paint over them. However, for cracks between 2 and 5mm wide, you need to widen them slightly by scoring along the crack with the edge of a blade. This might seem odd - why make the damage worse? But this removes loose plaster and helps the mixture bond with the existing plaster. You can also use this method to deal with nail holes and minor damage caused by DIY work.

Mixing The Plaster

Follow the manufacturer's instructions to mix the plaster, making sure to get a smooth and workable consistency. Alternatively, you can use a ready-mixed patching plaster - but choose a good brand!

Filling The Cracks

Use a putty knife, filling knife, or plastering trowel to apply a thin coat of patching plaster or joint compound mixture into the cracks. Fill them evenly, ensuring the mixture is slightly raised above the surface.

For large cracks, apply fibreglass mesh or jointing tape along the entire length. Press it firmly into the wet plaster or joint compound, ensuring it covers the entire crack.

When applying a joint compound or patching plaster, it's essential to apply a thin layer each time, as a thick coat will take longer to dry and it might fall out! If the cracks are deep, you could use a caulking gun to insert a filler before applying the repair patch.

Smoothing The Surface

Once you have applied the finish coat, use a damp sponge or a clean putty knife to smooth the surface of the repair. Feather the edges to blend the new plaster with the old.

Drying Time

Allow the plaster or joint compound to dry completely, following the manufacturer's recommended drying time. Avoid any unnecessary movement or disturbance during this period. You can also check out our post "How Long Does Plastering Take To Dry" for more additional insights.

Sanding And Finishing

Once dry, gently rub the repaired area using fine-grit sandpaper to achieve a smooth finish. Wipe away any dust with a damp cloth.

Decorating

Apply a coat of paint that matches the colour of the ceiling. Feather the paint slightly beyond the repair area to ensure a seamless blend with the surrounding ceiling.

Fixing plaster ceiling cracks requires patience, attention to detail, and the right tools. By assessing the damage, preparing the surface, and executing the repair methodically, you can restore your ceiling to its former glory. Remember to address any underlying issues to prevent future cracks.

If you encounter significant structural damage or feel unsure about the repair process, it's always advisable to seek professional assistance. With this step-by-step guide, you can confidently undertake the task of fixing plaster ceiling cracks and enjoy a beautifully restored ceiling in your home.

Minor Repairs To Blown Plaster

Whether you have a plaster and lath or plasterboard ceiling, you might be able to make minor repairs to sagging plaster.

With plaster and lath, the strips of wood are nailed directly into the ceiling joists, and the plaster sometimes loses its grip on this for several reasons. If the damage was caused by a leak, this will need to be fixed first, obviously. Next, take a flat piece of chipboard or plywood nailed to a supporting prop - a sturdy, square timber pole that reaches from floor to ceiling. Use this to contain the damaged area while you work above.

Lift the floorboards directly above the area in question, then make a loose mixture of bonding plaster and pour this over the damaged section. Leave the prop in place until the new plaster has dried, bonding the old plaster to the joists once again.

If the plasterboard has dropped, it's likely that it will need to be replaced. This should be a fairly simple repair, although you must make sure that you select the right size! Cut away the damaged area carefully, and then, if necessary, cut the new drywall to size before attaching it to the joists. Jointing tape will cover the seams nicely.

It's not absolutely necessary to apply a skim coat of plaster, but it does provide a superior finish.

Safety Notice: Artex & Asbestos

Until as recently as 1999, plaster produced to create textured ceilings (often called Artex, although this is only one brand) was strengthened by the addition of asbestos. So, if your Artexed ceiling was installed before this time, it's almost certain that it contains asbestos. To learn more about how to tell if plaster has asbestos, take a look at our post.

Because of this, it is essential to treat it with caution. If you want to remove the textured effect or replace the ceiling entirely, it has to be handled with care. This means that heavy sanding is not a good idea, and neither should you remove it by breaking it into pieces.

Although the risk is relatively small, it is still possible that you could release harmful fibres that have carcinogenic qualities. Top Notch Walls offers an Artex removal service, and we can also advise you further on how to deal with your ceiling if you have any concerns. Don't also miss our article "How To Cover Artex Without Plastering" - it offers valuable insights into this important topic.

Don't Be Afraid To Ask For Help!

This guide gives you the basics on how to repair cracks, along with a few other tips to help you, so you should be able to go ahead and sort out your ceiling.

However, not everyone will be confident about tackling this job. If you have any doubts, or you're uncertain about some of the steps we've provided here, then get in touch, and the friendly crew at Top Notch Walls will put you straight.

Sometimes cracks in plaster ceilings can indicate that there's a serious structural problem that needs immediate attention. If you suspect that this is the case, then don't hesitate! Call someone, whether it's a surveyor, a construction expert, or ourselves.

The sooner you call, the quicker the repair work can be completed and the less likely it will be to end badly.

In the meantime, most cracks in plaster ceilings are nowhere near as dramatic and can be fixed easily and without too much fuss. For everything else, the team at Top Notch Walls is here for you.

FREE Plastering Quote
Top Notch Walls
FREE Plastering Quote
Free Call Us
0800 086 2915
Connect with Us
Facebook
© 2024 Copyright Top Notch Walls.
Plastering footer image