Across the properties I manage, more injury reports come from stairs than from any other single feature, and when I look into them, the cause is almost never carelessness. It is geometry. A step that is a little taller than the ones around it, a handrail that stops short or is the wrong shape to grab, a riser height that changes halfway down, these are the things that put people on the ground, and they are all fixable defects, not bad luck. Stairs cause falls in patterns, and the patterns are worth knowing.
Consistency is everything
The single most important thing about a flight of stairs is that every step is the same. Building codes are strict about this for a concrete reason: your body climbs and descends stairs on autopilot, your foot expecting the next step to be exactly where the last one was. When one riser is even a fraction of an inch taller or shorter than its neighbors, your foot arrives where it expects the step and the step is not there, and you pitch forward or catch your toe. The tolerance codes allow between the tallest and shortest riser in a flight is small, often around three-eighths of an inch, precisely because a bigger variation is a genuine hazard.
This is why a single rebuilt or settled step in an otherwise uniform flight is so dangerous, it breaks the rhythm your body relies on, and it is the step people trip on again and again.
Riser and tread dimensions
Beyond consistency, the actual dimensions matter. Risers that are too tall or treads too shallow force an unnatural, precarious gait, especially on the way down. Codes set maximum riser heights and minimum tread depths, and older buildings frequently have stairs that predate current standards, steeper and with shallower treads than would be allowed today. Those legacy stairs are not automatically illegal, but they are measurably more fall-prone, and on a managed property they deserve extra attention, better lighting, solid handrails, and awareness that they are a known risk. The accessibility and stair-safety guidance from the U.S. Access Board spells out the dimensions that keep stairs walkable.
Handrails: the catch that has to work
A handrail exists to catch you when the geometry fails, and a surprising number do not actually work. Common defects: a rail that ends before the top or bottom step, exactly where people are most likely to stumble; a rail mounted too high or too low to be useful mid-fall; and a rail whose shape cannot actually be gripped, a wide decorative cap or a flat board you cannot close your hand around does not let you arrest a fall. A graspable handrail, roughly circular or with a graspable profile, continuous the full length of the stairs, is what turns a stumble into a recovery instead of a fall.
For any stairs used by the public or tenants, a functioning continuous graspable handrail is one of the highest-value safety features there is, and one of the most commonly deficient.
The management takeaway
Stairs are a documented, foreseeable hazard, which means unaddressed stair defects are exactly the kind of thing that turns an injury into liability. On the properties I manage, stairs get specific attention in inspections: measure for consistent risers, confirm handrails are continuous, graspable, and properly mounted, and add lighting where visibility is poor. A defect found and fixed is cheap; a defect known and ignored is the worst position to be in, the same principle that governs any common-area hazard a landlord or HOA is responsible for. And because visibility compounds geometry, good lighting on steps and paths is part of the same safety picture.
Frequently asked questions
Why do people trip on one specific step? Usually because that step’s riser height differs from the others, even slightly. Your body climbs stairs on autopilot expecting uniform steps, so an inconsistent riser, often a rebuilt or settled one, is where the foot lands wrong and the fall happens.
What makes a handrail actually safe? It must be continuous the full length of the stairs, including the top and bottom steps, mounted at a usable height, and graspable, a profile you can close your hand around. A rail that stops short or is too wide to grip cannot arrest a fall.
Are old, steep stairs illegal? Not necessarily; stairs built to earlier codes are often allowed to remain. But they are measurably more fall-prone than stairs meeting current riser and tread standards, so they warrant extra safety attention like good handrails and lighting, especially on rental or common property.