A levelling assembly. The pilaster sits on threaded studs or an adjustable bracket anchored into the floor slab, and those threads are turned to bring the upright plumb and the door line level before anything else is fixed.

The shoe is a cover, not a structural part. It slides down over the assembly once levelling is complete and is held by a grub screw, a spring clip or friction.

That is why a loose shoe is worth investigating rather than simply pushing back up: it is the access panel to the adjustment that controls whether the door latches, and a shoe that will not stay put often means the anchor below has moved.

Because it sits in the wettest, most chemically aggressive centimetre of the room. Mop water carrying detergent pools at the base of every upright, floor scrubbers drive it against the metal, and it dries slowly in a corner.

Chlorinated and acidic washroom cleaners are the real problem rather than water. Chlorides attack the passive layer on stainless steel, and repeated wetting and drying concentrates them exactly where the shoe meets the floor.

Specifying a higher stainless grade at the shoe than elsewhere in the cubicle is common and sensible, as is sealing the shoe to the floor so water cannot sit inside it unseen.

Enough to cover normal floor tolerance, typically a few tens of millimetres from the shortest to the tallest setting, with the shoe sized to hide the range.

That range is consumed quickly on a floor laid to fall, which washrooms often are. Across a run of cubicles the difference between the highest and lowest anchor point can approach the whole adjustment.

Where the fall is greater than the shoe can conceal, taller shoes are available, and the alternative is packing the anchor rather than stretching the levelling studs to their limit, which leaves the thread barely engaged.

Usually yes, if it is a two-piece or split pattern. Those wrap around the pilaster and clip or screw together, so a corroded shoe can be cut away and a new one closed around the upright in place.

A one-piece shoe has to pass over the end of the pilaster, which means lifting the panel off its anchors. On a braced run that also means releasing the headrail, so a single shoe turns into a partial strip-out.

Checking which type is fitted before quoting the work avoids a large difference in labour, and split shoes are frequently specified on refurbishments for exactly this reason.

Very little by design, though it does brace the base against casual knocks and keeps a foot or a cleaning machine off the anchor bolts.

The load path runs from the panel through the levelling studs into the floor anchor, and the shoe is outside that path. A missing shoe does not weaken the cubicle in the short term.

Over time it does, indirectly. Without the cover, water and detergent reach the anchor and the thread, and a corroded anchor is a structural problem even though the shoe that would have prevented it was not.

Most commonly a grub screw bearing on the upright, sometimes a spring clip inside the shoe, and on some systems a friction fit alone. All three rely on the shoe being the right internal size for the pilaster thickness.

That is the dimension to check when ordering. A shoe made for a 20 mm pilaster will not close around a 25 mm one, and one made for a thicker upright rattles on a thinner one however tight the grub screw.

Where the grub screw has been over-tightened it dimples the pilaster face, so a replacement shoe usually wants a fresh position rather than the old witness mark.

No, and that is one of the reasons ceiling-hung systems are chosen. With no upright reaching the floor there is no floor junction to cover, and no anchor sitting in mop water.

The whole floor is then clear for machine cleaning, which is why this arrangement is favoured in food production, healthcare and any washroom cleaned with a scrubber-drier.

The trade-off moves upward: the ceiling structure has to carry the full load of the partition, so the saving on floor hardware is paid for in the soffit supports.