Concrete Crack Repair

Ken Hanson Epoxy Coatings Leave a Comment

Just as in painting, installation of epoxy flooring is as much about the preparation as it is about application. High-quality concrete preparation requires careful attention to the repair of hairline cracks, spalling, pitting and major cracks. The time spent on concrete crack repair will significantly enhance the final appearance of your epoxy floor.

Concrete crack repair can vary considerably from job to job. As a general rule, the more northern the US state, the greater the potential for damage. Winter’s freeze-and-thaw can take its toll on the best laid concrete.

Minor Concrete Repairs

Small Hairline Cracks

When it comes to concrete crack repair, the old adage “size matters” certainly applies. Once the epoxy primer coat has been applied, small hairline concrete cracks (smaller than the width of dime) require a little siliconized acrylic latex caulk. Then, a quick scrape with a putty knife…and presto, you’re done!

(Just don’t apply siliconized acrylic latex caulk direct to concrete. The latter does not bond strongly to the concrete substrate.)

Saw Cuts and Tool Joints

Saw cuts and tool joints are intentional cuts in the concrete that provide “planes of weakness”. As concrete dries and shrinks, cracks (if any) tend to form in the saw cuts and tool joints…not randomly through the concrete slab. Like hairline cracks, saw cuts and tool joints, often seen in exterior concrete and garages, can be “repaired” with siliconized acrylic latex caulk.

Isolation Joints

Isolation joints are separations in the concrete that allow adjoining concrete slabs to move freely. For example, isolation joints exist where a vertical wall meets the horizontal floor. These joints can also be “repaired” by the addition of siliconized acrylic latex caulk. However, isolation joints can be large and may first require the addition of one or more backer rods prior to filling the space with the latex caulk.

Major Concrete Repairs

Large cracks, including cracks exceeding the width of a dime, large concrete indentations, and broken concrete edges are a very different animal. If you attempt to repair these problems with siliconized acrylic latex caulk alone, you’ll be back for re-repairs.

These issues require the preparation and application of quick-cure polyaspartic or polyurea, aggregate and solvent mixtures. For vertical damage and concrete with broken edges, a higher ratio of fine aggregate is used to create a “shapable” patch material.

For significant large-scale damage on a horizontal substrate, preparation and application of 3-component “cementitious” mixtures may be required. At, we use our 3-component Zycrete PMC to repair up to ¼” depth concrete imperfections. These mixtures are used as primer coats to simultaneously mitigate moisture and mask concrete damage.

The Wrap

Proper concrete preparation includes concrete crack repair. This can be simple in the case of hairline cracks or complex in the case of major concrete damage. Proper repairs will determine whether your installed epoxy floor is beautiful, functional and durable…or not! Yet another good reason to leave epoxy floor installations to the professional.

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