Delamination is when a coating separates from the concrete underneath it, or when one coat separates from another, usually showing up as peeling, bubbling, or flaking.
Understanding Delamination
Delamination happens when a coating loses its bond, either to the concrete below it or to a previous coat in a multi layer system. It can show up right away as bubbling during cure, or months later as peeling and flaking once the floor sees traffic, moisture, or temperature swings.
Common Causes of Delamination
The most frequent cause is inadequate surface preparation, such as coating over dust, laitance, sealers, or curing compound residue instead of a properly profiled surface. Excess moisture vapor coming up through the slab is another major cause, along with applying a coat outside its recoat window so the layers never chemically bond. Contamination from oil, grease, or cleaning chemicals left on the concrete can also prevent adhesion.
Spotting the Difference From Other Failures
Delamination is distinct from surface level defects like fisheyes or pinholing, which are cosmetic flaws within a single coat rather than a loss of bond between layers. A quick way to check is the tape test or a coin tap test: hollow sounding or easily lifted sections point to delamination rather than a surface blemish.
Preventing Delamination
Proper mechanical surface preparation, moisture testing before coating, and following the manufacturer’s recoat window are the three biggest levers a contractor has to prevent delamination. Because repairs almost always mean grinding out and reinstalling the affected area, prevention through good prep is far cheaper than the fix.
Also Called
Coating Failure, Peeling, Debonding
