How to repair cracks in walls

Cracked wall

If you have your own home or have ever rented a property for a living, then there is a high chance that you will come across cracks in the walls. These are also almost inevitable parts of the house. They can also be caused by a multitude of factors, such as faulty settling of the foundation, temperature changes, or even just normal wear and tear. While small cracks may not seem like a big deal, they can surely escalate quite quickly and become expensive if left unattended. But how to repair cracks in walls? Now, this is a question that most people think about, and we are here to cover everything about the types of cracks and the step-by-step repair process that will help you understand the procedure better.

Understanding Different Types of Cracks

Whether you are trying to identify some major structural problems or are just going through a routine checkup, cracks are something you might not want to ignore. There are also various types of cracks that can possibly occur, and each of them is listed below. You also get to know the characteristics of each of them, along with their causes.

Hairline Cracks

Just like the name suggests these types of cracks are often very thin cracks. They are even less than 1/16 inch wide and are most commonly found in a lot of properties. Hairline cracks are mostly superficial and do not mean much. They occur due to minor settling issues or due to natural expansion. It could also possibly occur due to the contraction of materials or aging of the building.

Structural Cracks

These are the cracks that seem to be more severe while also indicating potential structural issues. They could also exhibit various different patterns which include multiple intersecting cracks, bulging of materials, or wide openings. Structural cracks often require immediate attention, especially from a qualified professional, to assess the amount of damage it has done to the structure. Once the checking is done they then come up with appropriate repair methods.

Expansion Cracks

Concrete tends to move and expand under various conditions that it is exposed to. When it does not have enough room for expansion, there tend to be cracks occurring in the structure. The expansion joints are something that definitely cannot be ignored. Over time they could likely worsen and would even pose a major risk of structural damage and water ingress.

Shrinkage Cracks

Just like hairline cracks, shrinkage cracks often occur when poured concrete foundations dry out while losing moisture from them. New home structures are the ones to find shrinkage cracks, especially in the first year. These cracks are mostly vertical and could often not pose a grave danger to your foundation. The biggest risk, however, is present if you are present in an area with high levels of Radon Gas being leaked into your basement.

Tools and Materials Needed

No matter whether you are doing a DIY fixing project for repairing cracks at home or if you are calling a professional, you definitely require a certain set of tools and materials with you that will help you finish the process.


As for the tools that are required, here is an extensive list for the same:

  • Putty Knife
  • Wall Seal or Wall Filler
  • Sandpaper
  • Hammer
  • Chisel
  • Paintbrush
  • Caulking gun
  • Fiberglass mesh patch


As far as the materials are considered, the following materials would be required:

  • Drop cloths
  • Rags
  • Utility knife or scraper
  • Solution for heavy cleaning
  • Joint compound
  • Primer
  • Paint

Safety Gear

Safety should be at the top even while fixing a small crack, and a few of the safety equipment required could be provided as follows:

  • Dust mask
  • Safety glasses
  • Gloves

Preparation Before Repair

While repairing the cracks in walls will be an extensive process you might have to get some preparation done so that you never come across any such crack issue in the future. Here’s how you can prepare the walls for better cracks concealing.

Assessing the Damage

You can begin by assessing the damage caused by cracks. This helps to check its nature or type and also the extent to which it has spread. Identify whether the cracks are just superficial or are indicative of any underlying problems with the structure. You might also want to assess the depth, width, and pattern of the cracks to provide a better-tailored repair strategy.

Cleaning the Area

Next, you might want to clean the area before you actually begin the process. A clean space is to be ensured so that the filler or the repair seal can easily stick to the surface properly. Oftentimes, it could happen that when we try to repair a crack at home, we fail to clean it properly, and this causes the debris to stick to the seal, which leaves room for air. This results in the area not being airtight, which means the cracks will resurface again.

Removing Loose Debris

Removing any loose dirt, dust, or debris is important since they could hinder proper adhesion. You need to use a vacuum cleaner to get rid of these. You might also want to inspect the crack for protrusion or loose materials. Using a scraper or putty knife, you can gently remove them. This will ensure you now have a clean and smooth base for the repair to be done.

Step-by-Step Repair Process

While you can fix the crack almost instantly, what is important is to ensure there is a permanent fix to your crack issue. This can only be done if you follow the necessary step-by-step repair process for fixing the cracks in your walls. To help you understand the same, here is a detailed guide on the step-by-step process:

Step 1: Routing of cracks

Once all of the cracks have been cleaned and prepared properly you might want to check for wider cracks. And if there is the presence of wider cracks then you might want to consider creating a V-shaped groove along the crack by using a masonry chisel or a crack chasing saw.

Step 2: Filling up the crack

The next step, the most important step is to fill in the prepped crack. Now you can either choose to fill the cracks with a seal or a filler. Either way once the crack has been filled in, these crack filler or crack seal products will help close the gap.

Step 3: Layer addition for larger holes

If the walls consist of larger holes then it would require special care. Open the hole dust out any loose material present inside it and pray a bit of water to prep it. Once this is added apply the crack filler for the walls inside this large gap and spread it in a cris cross method for better grip of the next layer. Push it in evenly and then wait for this layer to dry before you apply the next one.

Step 4: Sanding of the surface

Once the crack has been completely sealed, you might want to execute the fourth step, which is to sand the surface for a finished look.

Step 5: Painting

The final step that will lead to a flawless execution would be to paint over the new surface once sanding is completed. The paint will give you the finishing touch you need to repair it. Once painted, the surface will appear in such a way that it never had any cracks.

Tips for a Professional Finish

While repairing wall cracks can be done by following a few steps, you might also want to take a look at how to get a complete finish such that there is no indication of any previous cracks.

Even the Application of Filler

It could be tempting to add on multiple layers and overfill the crack in the hope that it would fix the crack. However, it would be the opposite. The more you add, the more it could result in shrinkage as it dries up. This is why you need to follow the application slowly and even.

Sanding Techniques 

Proper smoothing of the surface will be important to achieve a visually appealing and seamless repair. Neglecting this could lead to an uneven surface even after you paint over it. Using sandpaper and blending it with the surrounding wall would be necessary.

Choosing the Right Primer and Paint

After the crack has been filled and it is dry, you will need to give it the last finishing touch. To do this, you need to select a paint and primer that would match the wall that is already existing. In this way, you get not just a seamless wall but also an additional layer of protection.

Blending Repaired Area

While painting you might want to see whether the level of paint is with the level of the existing wall paint. If not then again it could show some sort of elevation or depression if the layers are not proper.

Preventing Future Cracks

It’s not just enough to fix a crack and not take any preventive measures to avoid the cracks in the future. This will definitely result in a lot worse conditions. So preventing future cracks should also be a part of the repair process.

Maintaining Proper Moisture Levels

To stop wall cracks handling moisture is the most important step. You might want to apply special coatings that do not allow excess moisture to enter the walls.

Regular Inspection and Maintenance

You need to keep a log of regular inspections and maintenance. This will help spot any problems early on in the stage and help fix them right away. This, again, keeps away any major structural issues.

Addressing Structural Issues

Structural issues, especially with the basic foundation, are what also need to be checked. Once the base is strong it is hardly possible for any cracks to ever occur.


To sum up, cracks are definitely one of the most common problems that can occur, whether it is drywall, plaster walls, or even concrete walls. However, with the help of the right tools and materials, it is possible to fix the cracks. With a little bit of effort and patience, it is also possible to avoid cracks in the future and keep your home looking its best.


What is the best way to fill cracks in walls?

The best way to fill cracks in walls is by using suitable crack-fill powder. These are specially formulated to effectively seal and fill in the cracks.

How do you repair cracked plaster walls?

To repair a cracked plaster wall, you need to follow the steps given below:

  • Start by pressing gently to check the area that has cracks
  • Clean the area by using a putty knife
  • Now spread out the crack-filling powder to fill up the cracks
  • Using sandpaper to give it a finishing touch
  • Top this off by applying a layer of paint.

How do you permanently fix cracked walls?

You might want to close off the crack with proper crack fill powder and then take preventative measures such that cracks never appear again.

Are cracks normal after plastering?

Cracks are definitely one of the most common problems, even in plaster. However, you might want to see the materials used for plaster to avoid any unnecessary cracks.

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