Simple Concrete Slab Seam Repair

August 16, 2021

How to fix edge chips where one concrete slab meets another

Cold joints at the driveway/garage slab connection can get damaged over time from the movement when vehicles drive in and out. If the slabs are not adequately separated from each other, chips pop off the edges as the weight shifts from one slab to the other.

Steps to repairing the concrete chip damage

  • Clean out the damaged area. David uses a pressure washer.
  • Apply bonding agent to the clean damaged surface. Confine bonding agent to the damaged area, clean it from the finished slabs before it dries. Use a brush to apply it and a sponge to clean it up. 
  • Allow bonding agent to dry to a tacky texture, about five to ten minutes, depending on the weather.
  • Mix the repair mortar to a stiff mix. Add water slowly using a sponge to add little by little until the texture is stiff and wet.
  • Trowel the concrete into the damaged areas, keeping separation from the adjacent slab. Flatten the top into the slab, roughly round over the edge, and keep the new concrete from touching the adjacent slab.
  • Let each patch set up while you move on to the next damaged area.
  • Shape the partially-cured patch. Use a sponge to clean the adjacent surfaces and smooth the patched area into the shape you want: blending flat into the top of the slab and rounding over the edge.

A reminder that concrete is caustic and will burn your skin. Make sure to wash your hands if they come into contact with concrete, as David's do in this video.

—David Odell owns Odell Complete Concrete in southern California. His YouTube channel is updated regularly. Sometimes you can see him in Professional Remodeler magazine, too.

 


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