How To Make Simple Concrete Repairs

Did you know you can make simple concrete repairs like a driveway repair, concrete patch or crack repair yourself? The job requires few tools and no special skills – just a little bit of know-how you can get from this simple concrete repair guide. It's both fun (honest!) and satisfying — so let's get to it! 


Skill
Intermediate
Time
Few Hours
Cost
Less Than $500

What You Need for This Project

SAFETY NOTE:

Wear gloves, safety glasses, long sleeves, and long pants when drilling, hammering, or chiseling concrete.

Patching Cracks in Concrete 

The technique for patching cracks will depend on the size of the crack.

Narrow Cracks

  • Remove any loose debris from the crack and surrounding area with a wire brush and broom.
  • Narrow cracks can be filled with a masonry crack filler that comes in a cartridge designed to be used in a caulking gun. Or you can fill the cracks with a vinyl concrete patching compound applied and smoothed with a putty knife. Vinyl concrete patching compound does not require the use of a bonding agent.

Wide Cracks

  • Use a small sledgehammer and chisel to undercut the edges of the crack. Undercutting the crack makes it wider at the base than at the surface, providing a mechanical method of "keying" the patch in place for a more secure and permanent repair.
  • Clean the area in and around the crack with a wire brush and broom. Wash the area with a stream of water.
  • Mix vinyl patching compound as directed by the manufacturer and trowel the compound into the cracks. Tamp the mixture to remove air pockets. If you use patching mortar instead of vinyl patching compound, either mix it with bonding agent instead of water or coat the edges of the surface to be repaired with bonding agent.
  • Smooth the mixture with the trowel.
  • When the patch has set (see manufacturer's instructions for the patch compound you are using), smooth or brush the surface to match the surrounding area.


Simple Concrete Repairs



  1. 1

    Prepare the Area

    Remove any damaged or crumbling concrete. Use a small sledge hammer and chisel to undercut the edges of the damaged area. Clean the area in and around the damage with a wire brush and broom. Then wash the area with a stream of water.
  2. Steps:



  1. 2

    Make a Form

    Use a piece of wood as a form by securing it against the side of the area you intend to repair. Use bricks or other heavy objects to hold it in place. The top of the form should be flush with the desired height of the edge. The form will give you a guide for smoothing the patch.
  2. Steps:



  1. 3

    Make the Repair

    Mix vinyl patching compound as directed by the manufacturer and trowel the compound into the area to be repaired. Tamp the mixture to remove air pockets. If you use patching mortar instead of vinyl patching compound, either mix it with bonding agent instead of water, or coat the edges of the surface to be repaired with bonding agent.
  2. Steps:



  1. 4

    Finishing Up

    When the patch has set (see manufacturer's instructions for the patch compound you are using), remove the form and smooth or brush the surface of the patch as necessary to match the surrounding concrete. Keep off the patched area until it has had time to cure according to the manufacturer's instructions.
  2. Steps:

How to Repair Concrete Slabs or Walks



  1. 1

    Remove the Damaged Concrete

    Using a sledge hammer, break up the damaged area of the concrete into pieces. Make sure you break the pieces into small chunks (smaller than the thickness of the slab) as they will come in useful later. 
  2. Steps:



  1. 2

    Clean Up the Area

    Remove the larger pieces of concrete from the area and distribute the smaller pieces of rubble to create a firm bed on which to pour the new slab. Clean the edges of the remaining slab(s) with a broom. Brush the edges and rinse with water.
  2. Steps:



  1. 3

    Make the Form

    Set up wooden (2 x 4 or 2 x 6) forms along the edges of the area to be repaired. The tops of the forms should be flush with the desired height of the finished slab. The forms will give you a guide for smoothing the new slab area. Mix your concrete according to the manufacturer's instructions and dampen the area to be repaired.
  2. Steps:



  1. 4

    Finishing Up

    When the patch has set (see manufacturer's instructions for the patch compound you are using), remove the form and smooth or brush the surface of the patch as necessary to match the surrounding concrete. Keep off the patched area until it has had time to cure according to the manufacturer's instructions.
  2. Steps:



  1. 5

    Making the Pour

    Fill the area between the forms with concrete mix. Begin in one corner and work to the middle. Then, begin in the opposite corner and work to the middle again. Fill until the concrete reaches the tops of the forms. Using a board wider than the repair area, drag the board along the forms to smooth out the surface of the repair area. This is called screeding. Remove any excess concrete that piles up along the front of the board.

    Important Tip: Tap the sides of the forms to settle the concrete and to minimize bubbles.
  2. Steps:



  1. 6

    Time to Trowel

    Smooth the surface of the concrete with a darby. a long wooden trowel, working in large half circles from one side to the other. Stop when water appears on the surface. After the water has evaporated, smooth the surface with a trowel. Allow the concrete to set, then smooth or brush it to match the existing slab or walk. Insert a trowel between the concrete and the form and run it along the inside edge of the form.
  2. Steps:



  1. 7

    Match the Look

    To accurately match the look of the rest of the slab or walk, you may also need to run an edger along the forms and the new concrete. A hand edger is a special tool that rounds and shapes the edge of a poured concrete surface. A hand jointer or groover is a tool used to create a joint in a concrete surface-like a crack in a sidewalk. Use these tools as necessary to reproduce the look of the slab or walk you are repairing.

    Note: Keep off the patched area until it has had time to cure according to the manufacturer's instructions. A slow cure is best for concrete. For this reason, the manufacturer may recommend that you mist the fresh concrete with water and cover it with plastic for at least three or four days.
  2. Steps:

Do You Have Other Home Repair Projects?

We all have our own "lists" of to-do's in and around the house. Make them as easy on yourself as possible with our in-store home repair professionals. Visit your local Lowe's with your list and see how we can help you get them done the right way the first time.  SHOP ALL HARDWARE

How To Terms

Tools, products, materials, techniques, building codes, and local regulations change; therefore, Lowe's assumes no liability for omissions, errors, or the outcome of any project. The reader must always exercise reasonable caution, follow current codes and regulations that may apply, and is urged to consult with a licensed professional if in doubt about any procedures.

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