How Do You Repair Cracks In Plaster Walls?

Plaster walls can develop cracks, which can be a cause for concern not only for the structural stability of a building but also for the physical appearance of the structure. Over time, structures will naturally settle and shift, which will result in certain defects that are unavoidable.

It is crucial to have a solid understanding of how to fix cracks in plaster walls, regardless of whether you are renovating an older home or simply maintaining a more recent one. Within the scope of this article, we will investigate a variety of methods and suggestions for fixing cracks, ranging from minor hairline fractures to significantly larger and more important problems.


To ensure that your walls are returned to their initial condition and continue to be free of cracks for many years to come, we will provide you with the materials that you will require, as well as step-by-step instructions and frequent mistakes that you should avoid making.

How Do You Repair Cracks In Plaster Walls?

Repairing cracks in plaster walls involves a few key steps to ensure a durable and seamless fix. The approach depends on the size and type of cracks. Here’s a general guide on plaster wall repair:

Materials You’ll Need

  • Plaster or joint compound
  • Plaster tape or mesh
  • Putty knife or plaster spatula
  • Sandpaper (medium and fine grit)
  • Primer
  • Paint (matching wall colour)
  • Dust mask and safety goggles

Step-By-Step Instructions

Step 1: Prepare the Area

  • Clean the Crack: Use a utility knife or a small chisel to gently widen the crack slightly. This allows for better adhesion of the plaster or joint compound. Remove any loose debris or dust with a brush or vacuum.
  • Protect Surrounding Areas: Cover floors and furniture with drop cloths or plastic sheeting to catch any debris or plaster dust.

Step 2: Apply Plaster Tape or Mesh (For Larger Cracks)

  • For wider cracks, apply plaster tape or mesh over the crack to reinforce it. This step helps prevent the crack from reopening after repair.

Step 3: Apply Plaster or Joint Compound

  • First Layer: Use a putty knife or plaster spatula to apply plaster or joint compound over the crack. If you’ve applied tape, ensure the compound covers it completely. Smooth out the surface to blend with the surrounding wall.
  • Drying Time: Allow the first layer to dry according to the manufacturer’s instructions. This can take a few hours or overnight.

Step 4: Add Additional Layers

  • Depending on the size and depth of the crack, you might need to apply additional layers of plaster or joint compound. Each layer should be thinner than the previous one to ensure a smooth finish. Allow each layer to dry before applying the next.

Step 5: Sand and Smooth

  • Once the final layer is dry, use medium-grit sandpaper to smooth the surface. Then, use fine-grit sandpaper to create an even finish that blends seamlessly with the surrounding wall.

Step 6: Prime and Paint

  • Prime: Apply a coat of primer to the repaired area. This ensures that the paint adheres properly and creates a uniform finish.
  • Paint: Once the primer is dry, apply paint that matches the wall colour. You might need two coats for a seamless look.

Tips For Success

  • Consistency: Ensure the plaster or joint compound is mixed to the correct consistency. Too thick, and it won’t spread evenly; too thin, and it won’t adhere properly.
  • Smooth Transitions: When sanding, create a smooth transition between the repaired area and the surrounding wall to avoid noticeable bumps or ridges.
  • Safety Precautions: Always wear a dust mask and safety goggles to protect against dust and debris during sanding.

By following these steps, you can repair cracks in plaster walls effectively and ensure a long-lasting, professional-looking result.

What Can I Use For Cracks In Plaster Walls?

To repair cracks in plaster walls, you can use a variety of materials depending on the size and type of cracks. Here’s a list of commonly used materials and their applications:

Joint Compound (Spackle)

  • Use For: Hairline cracks and small cracks.
  • Description: A lightweight material that is easy to spread and sand. Ideal for minor cracks and imperfections.
  • Application: Spread over the crack with a putty knife or spatula, smooth out, and allow to dry. Multiple thin layers are better than one thick layer.

Plaster Patching Compound

  • Use For: Larger or deeper cracks.
  • Description: This compound is designed for heavier-duty repairs. It adheres well to plaster surfaces and provides a strong, durable repair.
  • Application: Apply with a putty knife, spatula, or trowel. Like joint compound, use multiple thin layers if needed, allowing each to dry before sanding.

Plaster Mesh or Tape

  • Use For: Cracks that are likely to reopen or need reinforcement.
  • Description: Comes in various widths and provides structural support to prevent cracks from reappearing. Tape can be self-adhesive or requires a compound to stick.
  • Application: Apply over the crack, then cover with joint compound or plaster patching compound. Smooth out and ensure the mesh or tape is completely covered.


  • Use For: Small cracks or joints where some flexibility is needed (like between the wall and ceiling).
  • Description: A flexible sealing material, available in acrylic, silicone, or latex varieties.
  • Application: Squeeze into the crack and smooth with a caulk tool or finger. Best for cracks in areas with minor movement or where flexibility is beneficial.

Flexible Patch Compounds

  • Use For: Cracks in areas subject to movement or vibration.
  • Description: These compounds are designed to flex slightly, preventing cracks from reappearing. Ideal for homes with significant settling or older buildings.
  • Application: Apply like joint compound or plaster patching compound. Allow to dry and sand as needed.

Epoxy Resins

  • Use For: Structural cracks requiring a strong, durable repair.
  • Description: These resins create a robust bond and are often used in situations where structural integrity is a concern.
  • Application: Follow the manufacturer’s instructions for mixing and application. Generally used for serious repairs or structural concerns.

Choosing The Right Material

  • For Hairline Cracks: Joint compound or spackle is generally sufficient.
  • For Larger Cracks: Plaster patching compound with plaster mesh or tape for reinforcement.
  • For Cracks in High-Flex Areas: Use caulk or flexible patch compounds.
  • For Structural Cracks: Consider epoxy resins and seek professional advice.

Before choosing a material, always assess the type and severity of the crack, and consider the conditions that caused it. This will help ensure you select the right product for a lasting repair.


Using the appropriate materials and strategy, repairing cracks in plaster walls is a task that can be accomplished with relative ease. To determine the most appropriate technique of repair, it is essential to have a thorough understanding of the many types of cracks and the factors that produce them.

For example, joint compound is used for little hairline cracks, plaster patching compound is used for bigger repairs, and reinforced mesh is used for structural integrity. The use of a methodical procedure, which includes cleaning, filling, smoothing, and finishing, guarantees a result that is both long-lasting and seamless.

Although it is often possible to repair cracks on your own, some cracks may indicate deeper structural difficulties. In such cases, it is vital to seek the counsel of a specialist. Cracks that are properly addressed not only restore the appearance of your walls but also contribute to the long-term health and safety of your home.

Cracks can be repaired by using special techniques. If you adhere to the suggestions that are presented in this article, you will be able to confidently address plaster wall cracks and achieve a faultless, smooth finish that will last.

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