Spalling is a specific damage that occurs in concrete due to the expansion and contraction of water in the concrete surface during freeze-thaw cycles. Spalled concrete can be recognized by severe flaking on the surface of a concrete slab. Patching spalling concrete can be done successfully, but it requires removal of the affected area, followed by the placement of a new thin layer of concrete. The new layer restores the strength and looks of your concrete surface and protects against further damage, extending the life of the concrete slab.
Things You'll Need
- Power washer
- Bonding adhesive
- Nap roller
- Concrete patch mix
- Electric drill
- Paddle drill bit
- Self-leveling compound
Clear the flaking concrete chips from the slab. Use a chisel and hammer to break chips away from the slab.
Use a broom to remove the chips, dirt and any other debris from the surface of the slab. Clean the slab surface using a power washer. Wash in a single direction, away from the foundation of any buildings. Allow the concrete to dry completely before continuing.
Place duct tape around the concrete slab, covering the edges of any bounding surfaces so the patching material will not spread over adjoining surfaces.
Use a nap roller to spread a layer of bonding adhesive across the entire surface of the concrete, including the area to be patched. Allow the adhesive to dry so it is tacky to the touch but no longer wet. The adhesive aids the patch in bonding to the old concrete.
Prepare a batch of concrete patch mix according to the manufacturer’s instructions in a large bucket. Use an electric drill with a paddle attachment to mix the patch thoroughly. Pour the patch material into the damaged area cleared with the chisel. Spread the patch using a trowel, smoothing it throughout the damaged area until level with the surrounding undamaged concrete.
Mix a batch of self-leveling concrete overlay. Add any colorant desired to the mixture during preparation. Pour the compound over the entire concrete surface including the patch. Spread the compound evenly across the surface of the concrete using a squeegee. Allow the compound to dry according to the manufacturer’s recommendations. As the compound dries it will level itself, creating a smooth, even surface over the concrete while also concealing the patched area.