Why Your Old Garage Floor Coating Peeled — and How to Avoid the Replay
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You can see it: the white discoloration under the coating, the lifting edges, the peeling sheet. An old coating that failed almost always tells you what to do differently next time.
The usual cause: prep, prep, prep
About 90% of coating failures trace back to inadequate surface preparation. Causes include:
• Skipped or insufficient profiling (concrete polished smooth doesn't bond)
• Acid etch instead of mechanical grinding (often inadequate)
• Coating applied over a contaminated surface (oil residue, dust, curing compounds)
• Moisture trapped under the coating from a slab that wasn't tested
• Coating applied in conditions outside the spec (too cold, too humid)
What proper re-prep looks like
If you're recoating a previously coated floor:
• All old coating must be removed mechanically — grinding or shot blasting
• The exposed concrete must be re-profiled to manufacturer spec (usually ICRI CSP 3-4)
• Moisture testing per ASTM F1869 (calcium chloride) or F2170 (in-situ RH) is non-negotiable
• Any cracks must be filled with semi-rigid polyurea or epoxy filler, sanded flush
Cost reality
Removing a failed coating typically doubles the cost of the recoat job. It's frustrating. It's also the only path to a coating that lasts.
What this means for you
If the new bid skips the removal-and-prep line items, ask why. The cheapest bid is usually the one that's going to peel again.
What contractors should know
Walking the customer through the prep — with photos of the grinder going to work — makes the cost story clear. Customers who see the work value it.
Before you call anyone out
If you're not sure whether the work was done right, the cheapest first step isn't a contractor callback or a paid third-party inspection — it's a documented second opinion you can refer back to.
Supervisr's Floor Coatings QA model follows industry standards and guidelines set forth by ICRI (Concrete Surface Profile / CSP guidelines), ASTM (F1869 / F2170 moisture testing), and the major resinous-flooring manufacturers. It can review floor coating photos for surface profile preparation, moisture test documentation, primer coverage, and broadcast or topcoat consistency. Upload photos of concrete surface profile (CSP grade), moisture test results, primer coverage, broadcast aggregate density, and topcoat application, and you'll get a documented evaluation back in minutes with citations to the specific standards involved. It's the same checklist a careful inspector uses — applied to your photos, on your timeline.
For homeowners, that documentation is your conversation-starter with the contractor (or, if needed, your insurer or warranty carrier). For contractors, it's the third-party verification that closes the conversation cleanly.
About Supervisr
Supervisr is an AI quality-assurance platform for floor coatings. It follows industry standards and guidelines set forth by ICRI, ASTM, and the major resinous-flooring manufacturers, and analyzes prep and application photos to predict coating performance.
Homeowners use Supervisr to verify a contractor's work without playing inspector themselves. Contractors use Supervisr to document quality at each milestone — protecting against warranty disputes and building a track record of verified work. For more on how Supervisr's QA model follows the published references for Floor Coatings installations, visit supervisrapp.com.