Repairs
Can a coated floor be repaired?
Yes, and what it takes depends on whether the damage is in the top of the film or the coating has let go of the concrete under it.
The short version
- Damage in the top of the film gets filled or recoated.
- A section that has let go of the concrete comes off and gets rebuilt from the slab up.
- A patch blends better in a flake floor than in a solid color, because the flake breaks up the line.
- A worn topcoat can usually be renewed over a sound system without redoing the floor.
- A repair can come very close. Somebody who knows where to look will still find it.
The two kinds of damage
The first kind is on top. A gouge from something dropped, a scuff, a scratch in the topcoat, a mark from a hot tool set down on it. The coating is still stuck to the concrete all around it and the system under it is sound. That is a surface repair.
The second kind is underneath. A patch of coating that has let go of the slab, usually because the bond was never made there or because water got under it. It sounds hollow when you tap it and the edges lift. Filling something like that does nothing, because the trouble is not the hole. It is the bond in the concrete around the hole.
What each one takes
On a bond failure the loose material comes off, and it usually comes off further out than the visible spot, because a repair has to get back to where the coating is genuinely stuck. Then that area gets prepped the way a new floor gets prepped and the system goes back down over it.
Surface damage is smaller work. The chip gets filled, the area around it gets abraded so the new coat has something to key into, and the coat goes over it. Where a whole floor has gone flat in the traffic lanes and the system under it is still sound, the usual answer is a fresh topcoat across the top rather than taking the floor off and starting again.
How well a repair blends
A flake floor hides one well. What you see standing over it is the pattern rather than the field, and fresh flake broadcast into a patch scatters the line so there is no straight edge to catch. That is one of the practical reasons flake is the usual choice in a garage.
A solid color is harder. It is a flat field with nothing in it to break up an edge, and a patch is a slightly different age of coating sitting in the middle of it. It can come very close. It is still a repair, and somebody who knows where it is will find it.
You can usually tell which of the two you have from a photograph and from whether the spot sounds hollow when you knock on it. Sort that out early. A chip in a topcoat and a section that has been taking water under the coating are different amounts of work, and the second one grows while it waits.