Over-lifting is raising a concrete slab past its target height during a lifting repair, an error that can crack the slab, create new trip hazards, or throw off drainage pitch.
In depth
Concrete raising is a precision job measured in fractions of an inch. Lifting force does not apply evenly across a slab, so pumping too much material too fast in one spot can crack the slab, tent it against a neighboring structure, or leave it higher than the surfaces around it.
Over-lifting is hard to undo. Unlike a slab that is slightly low, a slab that has been lifted too high usually cannot simply be pushed back down, so prevention through controlled, incremental injection is everything.
How Acme applies it. We lift in small, controlled bursts, monitoring the slab continuously with laser levels and straightedges, and we stop at grade, not past it. Slow, monitored lifting is a core part of our process and one of the clearest differences between specialists and general contractors who occasionally raise concrete.
Related terms: Slab Lifting, Injection Port, Change in Level, Concrete Cracking
Frequently asked questions
Can an over-lifted slab be fixed?
Sometimes, but it is difficult. Options like grinding or re-cutting are limited and visible. It is far better to lift correctly the first time with controlled injection.
How precise is polyurethane lifting?
Foam expands predictably in small injections, so an experienced crew can routinely land slabs within about an eighth of an inch of the target height.