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Overlay Failure - Repairing Stamped Concrete Overlays

By Chris Sullivan – ChemSystems, Inc.

Question:

What caused this stamped overlay on a patio to fail?

Stamp overlay failure

Answer:

While this is quite a devastating situation, and will cost both time and money to repair, the cause is quite simple and direct. Lack of surface preparation causes 90% or more of overlay failures, and is without a doubt what caused this failure.

In most decorative overlay projects, surface preparation should cost more and take longer to perform then the actual overlay installation itself. Creating a profile (or degree of roughness) of at least #6 on the International Concrete Repair Institute (ICRI) surface preparation scale is mandatory for successful adhesion. The surface needs sufficient "bite" for the overlay to bond, otherwise delaminating failure can result. As can be seen in the picture, the surface under this overlay is smooth, with little to no profile.

Unfortunately, not much can be done to save this patio overlay. The remedy involves removal of the entire overlay, proper surface profiling using a mechanical scabbler or scarifier, and re-application of the overlay. To find out more about surface profile, contact the International Concrete Repair Institute.

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