How to Fix Cracks in Plaster Walls: The Ultimate Guide
Over the years, the foundation of your property will shift. This will ultimately take a toll on your plaster walls, resulting in cracks, indentations or other defects. If you’re planning on redecorating your home or office, a fresh coat of paint just won’t cut it. With this in mind, it’s a good idea to fix the cracks before starting your renovation project. Read on for our step-by-step guide on how to fix cracks in plaster walls.
When Should You Worry About Plaster Cracks
In most cases, cracks in plaster are nothing major to worry about. In fact, you can even expect to see slight cracks as a newly plastered wall dries out. However, in other cases, cracks are a sign of serious structural damage that requires immediate attention.
As a general rule of thumb, how wide the crack is can tell you how serious the problem is. For instance, plaster cracks are considered to be serious when they are between 15mm to 25mm wide. If the crack is over 25mm wide, there may be something wrong structurally.
It’s worth noting that not all plastic cracks are immediately apparent. Sometimes they will be in hard-to-see areas, such as around a window or door frame, or even behind furniture. So, it makes sense to regularly check for cracks, both small and big, in these areas. For more information, read our blog on when to worry about cracks in plaster walls.
The Different Types of Plaster Cracks
Plaster cracks can manifest in various forms, each a sign of particular underlying issues. One common type is known as peeling plaster cracks, where large sections of plaster detach from the surface, often resulting from poor adhesion and typically caused by inadequate surface preparation before plaster application. Insufficient bonding between the plaster and the substrate or the use of incompatible materials can contribute to this problem.
Another prevalent type of plaster cracks is shrinkage cracks, which branch out and spread across walls or ceilings. These cracks occur as the plaster dries and shrinks, leading to the development of fissures. Shrinkage cracks are common in freshly applied plaster and can be exacerbated by factors such as rapid drying, improper mixing of plaster materials, or insufficient curing time. Minor shrinkage cracks can be managed by filling them with plaster, but it’s crucial to address the root causes to prevent recurrence.
Hairline cracks are thin and subtle, often resembling spider webs on the plaster surface. These cracks can be attributed to a variety of factors, including structural movement, settling of the building, or temperature fluctuations. While hairline cracks may not pose an immediate threat, monitoring and addressing the underlying issues can prevent further deterioration over time.
Understanding the different types of cracks and their causes is important when looking to repair cracks in plaster walls. By identifying the root causes, homeowners and professionals can take targeted measures to repair the plaster and prevent the recurrence of cracks, ensuring the long-term stability and aesthetic appeal of the wall or ceiling.
Plaster Vs Drywall Repairs: The Key Differences
It’s fair to say that repairing plaster is trickier than fixing drywall. Yes, drywall repair is a multi-step process. However, repairing drywall is much more straightforward. The reason behind this is quite simple, drywall is constructed using one layer that has no backing. This means that it’s possible to simply cut through drywall and replace the entire portion that needs fixing without tearing down the whole wall.
Plaster walls, on the other hand, are built up in layers. The number of layers will depend on the roughness of the surface being plastered. But generally, plaster walls are constructed of at least two layers: the first being the outer layer of plaster and the second being the inner metal or wooden lath.
As plaster walls have several layers, it’s much more difficult to cut through the wall and replace the section that needs fixing. It’s likely that as you start to tear out one chunk, other chunks that don’t need fixing will fall out too. Essentially, it’s a never-ending process that may result in the entire wall collapsing. For this reason, it makes sense to fix only the cracked sections.
Whilst repairing a plaster wall may seem like a tedious process, remember, patience is king. After all, preservation is the most cost-effective and time-efficient solution.
Fixing Cracks In Plaster Walls: Step-By-Step Guide
Trust us, we understand that fixing cracks in plaster walls may seem daunting. But it doesn’t have to be. You can easily repair cracks using tools and materials that you can buy from your local hardware store.
What Equipment You’ll Need
Before you start repairing the crack, there are a few things you’ll need to have on hand. The tools and materials you need include:
- Sandpaper
- A pair of scissors
- A chisel
- A Stanley knife
- A filler knife
- Drywall tape
- Drywall joint compound
- A tray to mix the drywall joint compound if necessary
- A vacuum cleaner
How to Fix Cracks In Plaster Walls In 7 Easy Steps
In nine simple steps, you can repair plaster cracks.
1. Score the Crack
It’s best to start by scoring the crack with a Stanley knife. Simply cut along the edge of the crack to open it up. This will create a larger surface for the drywall joint compound to stick to. When scoring the crack, it’s a good idea to go as slowly as possible to ensure that you’re not opening the crack too much.
Top tip: remove any small pieces of leftover plaster and dust the crack with a vacuum cleaner.
2. Prepare the Drywall Tape
Using scissors or a Stanley knife, cut one or more pieces of drywall tape that are the same size as the crack. It’s wise to do this step before preparing the drywall compound, as the compound can dry quite quickly, making it difficult to apply the tape in time.
3. Mix the Joint Compound
Next, follow the instructions on the package to mix the drywall joint compound.
4. Spread the Joint Compound on the Crack
Once you’ve mixed the joint compound, use your drywall knife to apply a thin layer of the mixture to the crack. Don’t forget to make sure that the edges of the crack are completely covered.
5. Position the Drywall Tape
As soon as you’ve applied the mixture, immediately cover the crack before it dries. Then gently smooth out any wrinkles or bumps with the drywall knife. Then leave the area to dry completely.
6. Sand the Area
Using sandpaper, carefully sand down the area to make it smooth and even. Remember to not sand down to the tape.
7. Vacuum the Area
As with any other task, the final step is to clean up. Simply use a vacuum to get rid of any dust or debris plaster. Finally, wipe the patch with a dry cloth and your plaster wall is ready to be painted. Read our blog on painting new plaster to discover useful tips and tricks.
Repairing Different Types of Plaster Cracks
The reality is, that not all plaster cracks are the same. So, it’s no surprise that the process of repairing plaster cracks of different sizes and in different areas can vary. Therefore, it’s important to know how to repair different types of plaster cracks.
Repairing the Corners of Plaster Walls
Cracks can also occur in hard-to-reach areas, including around door and window frames. Whilst it may be slightly more difficult to notice cracks in these areas, it only takes one extra step to fix such cracks.
If you follow the above process, the only extra step you need to take is to apply one more piece of drywall tape. Next, apply another layer of joint compound to the taped area and sand as usual. It’s that simple.
Deep Cracks in Plaster Walls
Deep cracks can really impact the structural integrity of your property. That’s why we’re sharing our tips on how to fix deep cracks in plaster walls.
1. Remove the Debris
First, it’s best to use a chisel to remove any excess plaster from the deep crack.
2. Fill the Crack with Newspaper
In order to add some extra support and stability, it’s a good idea to fill the crack with newspaper.
3. Apply the Plaster
Once you’ve filled the crack with newspaper, spread a layer of plaster over the filled crack.
4. Leave the Plaster to Dry
It’s important to give the plaster time to dry before going in with another layer of plaster. To learn more about the plaster drying time, head over to our blog where we answer all your plaster drying questions.
5. Apply Another Layer of Plaster
As you’re working with a deep crack, you’ll find that one layer of plaster just won’t do the job. Hence, it’s a good idea to continue applying additional layers of plaster until the crack and the wall is level.
6. Sandpaper the Wall
Once the area is dry, sand it down until it’s even and smooth.
Repairing Recurring Cracks in Plaster
It’s pretty normal for cracks to reappear over time. If you notice cracks recurring, simply follow the process described in our ‘how to fix cracks in plaster walls in 7 easy steps’ section.
Repairing Plaster Cracks Before Painting
To ensure a flawless finish when painting plaster walls, it’s essential to address the various cracks promptly. Common signs that your plaster has cracked beneath your paint include:
- Peeling plaster cracks – where large patches detach, require expert consultation
- Shrinkage cracks – spreading across walls or ceilings, can be filled with plaster for minor cases
Timely resolution is crucial to prevent worsening issues. Familiarise yourself with the process of fixing cracks before painting to achieve a lasting result, or enlist professional help for more severe cracks.
If you’re concerned about deep or recurring cracks, it’s sensible to seek the services of a plastering specialist like us at AB Drylining. We can help you achieve a smooth, crack-free finish, allowing you to get your renovation project underway in no time. Our plastering and rendering services are offered to clients across the South West, including Bristol, Bath, Swindon and surrounding areas. Simply give us a ring on 01225 941006 or submit an enquiry online. We look forward to chatting with you soon.
FAQ
How to find the best filler for cracks in plaster walls?
It’s nearly impossible to provide a clear-cut answer; however, as long as the filler is durable, hard-wearing and can be easily sanded down, it should provide the results you’re looking for.
Is it normal for cracks to occur in plaster walls?
Yes, cracks in plaster are quite common. This means there’s no need to be worried if you start to notice cracks in your walls. After all, the issue can be fixed in a matter of minutes.
If the crack is large, however, it’s wise to contact a plastering expert.
Can I fix cracks in plaster walls before redecorating?
It’s sensible to fix any cracks in plaster walls before painting, as they will simply reappear. To solve the issue, follow our step-by-step method detailed above.
