How to Repair Cracks in Plaster Walls

Plaster walls add charm and character to any home, but over time, they can develop cracks. These cracks not only affect the aesthetic appeal of your walls but can also lead to more significant structural problems if left untreated. However, repairing cracks in plaster walls is a task that you can tackle yourself with the right tools and techniques. In this article, we will guide you through the process of repairing cracks in plaster walls step by step.

Cracks in Plaster Walls

Cracks in plaster walls can be unsightly and may undermine the overall aesthetics of your home. However, with a little effort and the right materials, you can repair these cracks and restore the beauty of your walls. Let’s dive into the process step by step.

Prepare the crack

Before you begin the repair, it’s important to assess the condition of the crack. Use a utility knife to clean out the crack and remove any loose plaster or debris. To determine if the plaster is detached from the wall, press your fingers against it in several spots around the crack. Listen for hollow sounds by tapping your knuckles against the plaster.

Apply joint compound

Using a putty knife, apply a thin coat of joint compound to the crack. For wider cracks, it’s advisable to use fiberglass mesh tape to cover the crack before applying the joint compound. This tape helps strengthen the repair and prevents the crack from reappearing.

Sand and let dry

Once the joint compound is dry, sand the repaired area using medium- or fine-grade sandpaper. This will remove any high spots and ridges while feathering the edges of the repair. Use a tack cloth to wipe away the dust. Allow the compound to dry completely, which typically takes up to 24 hours.

Apply additional coats

If the crack is still visible after the first coat of joint compound, apply additional coats. Make sure to let each coat dry completely before applying the next. This step may require some patience, but it is crucial for achieving a seamless repair.

Prime and paint

Once the joint compound is dry and the crack is no longer visible, it’s time to prime and paint the repaired area. Choose a primer that matches the surrounding wall and apply it evenly. After the primer has dried, paint over the area with a color that matches the rest of the wall. This will ensure a smooth and cohesive finish.

Working with plaster walls

It’s important to note that working with plaster walls is different from working with sheetrock. Plaster walls can be heavier due to the presence of wood lath behind them. They may also have structural anomalies, such as horizontal studs. Keep these factors in mind while repairing cracks to ensure a successful outcome.

Enlarging small cracks for proper repair

In some cases, it may be beneficial to enlarge small cracks before fixing them. Small plaster cracks have a tendency to reappear over time. By enlarging the crack and properly repairing it, you can prevent future issues and achieve a more durable repair.

Products for plaster repair

There are several products available in the market that can assist you in repairing plaster walls. Consider using options like Big Wally’s Plaster Magic Repair Kit, UGL Spackling Paste, USG All-Purpose Joint Compound, or Zinsser Guardz Problem Surface Sealer. These products are specifically designed for plaster repair and can help you achieve optimal results.

Safety precautions

When working with plaster, it’s essential to prioritize safety. Wear safety goggles, a long-sleeve shirt, and cotton work gloves to protect your eyes and skin. Additionally, use a sanding respirator to prevent inhalation of dust while breaking dried plaster or when mixing compounds. Safety should always be your top priority.


Repairing cracks in plaster walls is a manageable task that can be accomplished with the right tools and techniques. By following the steps outlined in this article, you can restore your walls and enhance the overall appearance of your home. Remember to take the necessary safety precautions and invest in quality repair products for long-lasting results.


  1. Q: Can I repair plaster cracks without using joint compound? A: Joint compound is recommended for repairing plaster cracks as it provides a smooth and durable finish. It helps reinforce the repair and prevents the crack from reappearing.
  2. Q: How long does it take for the joint compound to dry? A: The drying time for joint compound varies depending on factors like humidity and temperature. Generally, it takes up to 24 hours for the compound to dry completely.
  3. Q: What type of sandpaper should I use for sanding the repaired area? A: For sanding plaster repairs, it’s best to use medium- or fine-grade sandpaper. This will help remove high spots and feather the edges of the repair.
  4. Q: Are there any specific safety precautions I should follow while repairing plaster walls? A: Yes, it’s important to wear safety goggles, a long-sleeve shirt, and cotton work gloves to protect your eyes and skin. Additionally, use a sanding respirator to prevent inhalation of dust during the repair process.
  5. Q: How can I prevent small plaster cracks from reappearing? A: Enlarging small cracks and fixing them properly can help prevent their recurrence. By providing a more robust repair, you can minimize the chances of cracks showing up again.

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