A coating that is lifting has a reason. Finding out which one applies matters more than choosing what goes down next, because a second floor installed over the same conditions fails exactly like the first.
Here are the three, with how to tell them apart.
1. The slab was never properly prepared
The most common by a wide margin.
What happened: the concrete was acid-etched, pressure-washed or lightly scuffed instead of being ground with diamond tooling. Acid etching opens the surface unevenly and leaves residue behind. The coating grips in some places and not others, and it looks perfect on day one.
How to tell: pick up a loose piece and look at the underside. If it is clean and glossy with no concrete stuck to it, the coating never bonded to the slab at all. It was sitting on top like a sticker. Look at the slab where the coating came away: if it is smooth and closed rather than open and porous, that confirms it.
The pattern: large flexible sheets lifting, often starting at an edge or the garage door line and spreading.
The fix: remove everything and grind properly. There is no shortcut and there is no product that compensates.
2. Moisture coming up through the slab
What happened: water vapour is moving up through the concrete and arriving at the underside of the coating, where it cannot get out. Pressure builds and pushes the coating off.
This is common in Birmingham for a specific reason: a great deal of housing here predates the routine use of polyethylene vapour barriers under slabs. The concrete is often fine. It simply has nothing between it and the ground.
How to tell: bubbles and blisters rather than peeling. Often in a patch in the middle of the floor rather than at the edges. Frequently with a chalky white residue underneath, which is dissolved salts carried up with the moisture and left behind when it evaporated.
Where it happens: basements most of all, garages on older slabs, lower levels cut into a slope, and anywhere on a hillside lot with soil against a wall.
The fix: test the slab, then a moisture-mitigating primer sized to the readings. Sometimes the better answer is drainage work outside first.
3. Hot tyre pickup
What happened: a warm tyre bonded to a rigid coating and pulled it off the slab.
How to tell: unmistakable. The damage is in the shape of your tyres, in the exact positions where you park, and the rest of the floor is untouched.
Why here: cars come home hot from the interstate for six months of the year, and traditional epoxy cures rigid rather than flexible.
The fix: change the system. A flexible polyurea base with a polyaspartic topcoat does not have this failure mode.
The two-minute diagnosis
Pick up a loose piece.
Clean glossy back, no concrete attached, coating lifting in sheets: preparation.
Blisters and bubbles, white powdery residue underneath: moisture.
Damage only where the car parks, tyre-shaped: hot tyre pickup.
Concrete firmly attached to the back of the piece, and the damage is mechanical, a gouge or an impact: not a bond failure at all, just damage, and often repairable locally.
What not to do
Do not let anybody recoat over it. New product on top of a failing bond fails at the same bond line, and now you have paid twice. Anybody offering this is selling you a repeat.
Do not accept "bad product" as an explanation. Product is rarely the cause. Preparation and moisture are. If a contractor cannot tell you why your floor failed, find one who can.
Do not assume it is urgent. If it is cosmetic and stable, leaving it is a legitimate choice. It becomes urgent when it starts spreading, because water then reaches bare concrete under the remaining coating and accelerates the process.
What it costs to fix
The uncomfortable part: removal frequently costs more than the new coating.
A poorly bonded floor can be scraped up quickly, which is cheap. A well-bonded coating that failed for another reason has to be ground off, which is slow and consumes diamond tooling. Floors with two or three layers from successive attempts are worse again.
This is why a quote to fix a failed floor is not comparable to a quote for bare concrete, and why you should be suspicious if somebody prices them the same.
Can just the bad patch be redone?
Sometimes. It works when the failure is genuinely localised and the surrounding coating is well bonded, which usually means hot tyre damage on an otherwise sound floor. The area gets ground back to sound edges, feathered and recoated, and a fresh topcoat over the whole floor hides the join.
It does not work when the cause is general. If the slab was never ground, the parts that have not failed yet are going to.
More on the process at repair and recoating. For what should go down instead, see polyaspartic coating.
Common questions
My floor is only two years old. Should it be failing?
No. A properly prepared floor should give you well over a decade. Failure at two years points at preparation or moisture almost every time.
Can I fix it myself?
Removal is the hard part and it is genuinely heavy work. The diagnosis you can do yourself in two minutes, and it is worth doing before you call anyone.
Is the concrete underneath damaged?
Usually not. Coatings fail at the bond line, and the slab beneath is normally intact. Moisture failures occasionally leave salt deposits that need cleaning off.
How do I stop it happening again?
Grinding rather than etching, a moisture test where the slab warrants one, and a flexible system in a garage. In that order.
The contractor blamed the product. Is that plausible?
Rarely. In this trade the causes are overwhelmingly preparation and moisture, and a contractor who reaches for the product explanation is usually avoiding the other two.
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