DIY Guide to Seal Cracks in Your Concrete

Cracks in concrete surfaces can be more than just an eyesore. They can lead to water damage, structural issues, and costly repairs if left unattended. Fixing these cracks yourself is a practical way to maintain your home’s foundation, driveway, or patio without calling in expensive professionals. This guide walks you through how to repair and seal a crack in concrete using a crack chaser blade on an angle grinder and Sika Flex sealant. It’s a perfect weekend project for any homeowner ready to tackle concrete repairs with confidence.

Using an angle grinder with a V-shaped crack chaser blade to efficiently repair and widen a concrete crack for enhanced durability.

Tools and Materials You Will Need

Before starting, gather these essential tools and materials:

• Angle grinder with a crack chaser blade: This blade is designed to widen and clean the crack for better sealant adhesion.

• Sika Flex sealant: A flexible, durable sealant ideal for concrete cracks.

• Wire brush or vacuum: To clean out dust and debris from the crack.

• Chisel and hammer (optional): For removing loose concrete pieces.

• Protective gear: Safety glasses, gloves, and a dust mask.

• Caulking gun: To apply the sealant smoothly.

• Water and sponge: For cleaning the surface before sealing.

  
  

Having everything ready will make the repair process smoother and more efficient.

Preparing the Crack for Repair

The key to a long-lasting repair is proper preparation. Start by inspecting the crack to determine its size and depth. Small hairline cracks may not need this extensive process, but wider cracks benefit from it.

1. Cut the crack with the crack chaser blade

   Attach the crack chaser blade to your angle grinder. Carefully run the blade along the crack to widen it to about 1/4 inch wide and 1/2 inch deep. This creates a clean groove for the sealant to bond with and removes any loose or weak concrete edges.

   
   

2. Remove debris and dust

   Use a wire brush or vacuum to clear out all dust, dirt, and loose particles from the groove. Any debris left inside will prevent the sealant from adhering properly.

   
   

3. Clean the surface

   Wipe the area with a damp sponge to remove remaining dust. Let it dry completely before applying the sealant.

   
   

Taking time on this step ensures the sealant will stick well and last longer.

Applying Sika Flex Sealant

Sika Flex is a popular choice for concrete crack repairs because it remains flexible after curing, allowing it to handle slight movements in the concrete without cracking again.

1. Load the sealant into the caulking gun

   Cut the nozzle of the Sika Flex tube at a 45-degree angle to match the width of the crack. Insert the tube into the caulking gun.

   
   

2. Apply the sealant into the groove

   Slowly squeeze the trigger and fill the crack groove with sealant. Make sure to push the sealant deep into the crack to fill all gaps. Avoid leaving air pockets. For a Cleaner look, you can tape the sides of the area beforehand to avoid any potential mess.

   
   

3. Smooth the sealant

   Use a putty knife or a gloved finger dipped in soapy water to smooth the surface of the sealant. This step helps the sealant bond better and gives a neat finish.

   
   

4. Clean up excess sealant

   Wipe away any extra sealant around the crack before it cures.

   
   

5. Allow curing time

   Follow the manufacturer’s instructions for curing time, usually 24 to 48 hours. Avoid walking or driving over the repaired area during this time.

   
   

Two tubes of Sika Pro Select Crack Flex Sealant rest on a textured concrete surface, highlighting their promise of durable and flexible crack repair.

Tips for a Successful Repair

• Work in dry weather: Moisture can prevent the sealant from curing properly.

• Wear protective gear: Concrete dust and sealant chemicals can irritate skin and eyes.

• Use the right blade: A crack chaser blade is designed specifically for this task and will make the job easier.

• Don’t rush the curing process: Patience ensures a strong, flexible seal.

• Inspect and maintain: Check repaired cracks periodically and reseal if needed.

  
  

When to Call a Professional

While many cracks can be repaired with this method, some situations require expert attention:

• Cracks wider than 1/2 inch

• Cracks caused by structural issues or settling

• Cracks that continue to grow after repair.

  
  

If you would like us to do this repair for you or notice any of the signs listed above, please click HERE to get a quote.

Finished concrete crack sealed with Sika Flex showing smooth surface