Sidewalk trip hazards are the cheapest liability on a commercial property to fix and the most expensive to ignore. A displaced slab does not close a building or stop traffic, so it sits on the walk-around list for years while everyone steps around it. Then someone catches a toe on it, and the incident report asks how long the condition existed and what was done about it. The answer to that question is usually written in your maintenance records, or in the absence of them.
The threshold most inspectors work from is small. A vertical change in level of a quarter inch or more is generally treated as a hazard, and anything between a quarter and a half inch is expected to be beveled rather than left square. Above a half inch, you are looking at a ramp or a repair, not a bevel. That is a much smaller number than most property managers picture, which is why walking a property with a tape measure or a coin for reference turns up more than walking it by eye.
Four conditions cause most of it. Tree roots lifting one edge of a slab is the classic, and the most likely to return if the root is not addressed. Soil settlement drops a slab at a joint, usually near a downspout, a utility trench, or a curb where the fill was never fully compacted. Freeze-thaw heave pushes panels up over winter and sometimes leaves them a fraction high in spring. And ordinary joint deterioration widens the gap between panels until the edges spall and the lip becomes a catch point.
The fix depends on which one you have, and matching them matters. A quarter-to-half-inch lip from settlement can often be ground down to a compliant bevel in an afternoon with no concrete work at all. A slab that has settled evenly can sometimes be lifted back into position rather than replaced. But a slab pushed up by a live root will come back if you only grind it, and a panel cracked through with spalled edges is past the point where surface treatment helps — that one gets removed and repoured. Grinding a slab that needed replacement buys you a season and a second bill.
Sidewalk work also has an accessibility dimension that is easy to miss. If the walk is part of the accessible route from parking to the entrance, the repair has to leave the route within its required slopes and keep the surface stable, firm, and slip resistant when it is done. A repair that removes the trip hazard but leaves the panel pitched wrong has fixed one problem and created another. When the walk connects to accessible parking, ramps, or curb access, it is worth having the whole route looked at rather than the single slab.
Build a record while you are at it. Walk the sidewalks twice a year — spring after the thaw, and late summer before falling leaves make edges hard to see — and note location, measured height, and probable cause for anything over a quarter inch. Photograph what you find. That log does two things: it lets you batch repairs into one mobilization instead of paying to bring a crew out for one slab at a time, and it shows a documented inspection and response program if anyone ever asks. Late summer is the right season for the concrete side of the work, with warm days for curing and dry ground for excavation.
If your walks have a handful of lips you have been stepping over, a free assessment can measure what is actually there, sort the grind-and-bevel candidates from the panels that need replacement, and tell you which ones have a root underneath that will undo the cheap fix.