Concrete Repair, Concrete Floor Repair — Cracks

Cracks are to concrete what death and taxes are to life — inevitable.

But at least cracks can be repaired.

Static cracks v. moving cracks
Hairline cracks generally fall into the static crack category — they don't move and they're not going to. They're typically surface cracks that were caused by one-time events, like drying shrinkage. Tight, static, surface cracks can be coated with most polymer-modified cementitious overlays and never seen again. However, if these same hairline cracks are on a floor that's acid-stained, they may go from practically invisible to far more noticeable if the stain sinks in and darkens them. This could be seen as a desired effect, but it could also be seen as a blunder.

Sealers, tinted or otherwise, can also inadvertently highlight the hairline cracks in a floor in an unattractive way. “The risk is, the sealer flows down into the crack and leaves a little sink area, and when light shines across it, it accentuates the crack,” says Seth Pevarnick, a technical field consultant specializing in decorative concrete for Ardex Engineered Cements. “In that situation, when it just a hairline, I'd just leave it go. Yeah, you may see it when you mop it, but when it dries you don't see it anymore.”