A door kit covers the moving door and its frame edge: hinges, latch and keeper, stop or bumper, pull and usually a coat hook. It is scoped to one leaf.

What it almost never includes is the structural ironmongery holding the cubicle up. Pilaster shoes, headrails and headrail brackets, alcove clips and panel-to-panel brackets are ordered against the partition layout rather than the door count, because a run of six cubicles needs seven pilasters but six doors.

Fixings are the other common omission. Some kits ship with machine screws sized for one panel thickness and none for the wall, so the anchors that suit the wall substrate have to be specified separately.

Three dimensions decide it: the door thickness, the pilaster thickness and the hole centres already drilled into both. A kit whose latch body is cut for a 20 mm door will not close properly on a 25 mm one, and a hinge with different centres means drilling fresh holes through a laminate face.

Mounting style matters as much. Floor-anchored, overhead-braced, ceiling-hung and floor-to-ceiling systems load their hardware differently, and hinges made for a braced cubicle assume something is restraining the pilaster overhead.

Where the original system cannot be identified, measuring the existing hole pattern and door thickness before ordering is faster than returning a kit, because the holes are the part that cannot be undone.

For cam and gravity hinges, yes. Those hinges are cut so the door parks in one direction when released, and a left-hand cam fitted to a right-hand door will swing the wrong way or fail to hold the open position at all.

Many modern kits sidestep this with reversible or universal hinges that can be flipped or re-pinned on site, which is why a single kit reference can cover both hands. The latch and keeper are usually symmetrical and less fussy.

Handing is read from outside the cubicle looking at the door. Getting it wrong is recoverable with universal hardware and expensive without it, so it is worth confirming before the order rather than on the day.

Only for a single cubicle. Kits are sold per door, so a four-cubicle washroom needs four, and an accessible cubicle usually needs a different one again because its door is wider and often outward-opening.

Quantities also diverge from the door count for everything structural. A run of cubicles has one more pilaster than it has doors, and a run against two walls needs alcove hardware at each end.

Ordering one spare kit for a large installation is common practice. Cubicle hardware is drilled to a pattern, and a single damaged latch found mid-fit otherwise stops the cubicle being handed over.

Because the panel is already drilled. Cubicle panels are compact laminate, solid grade laminate or faced board, machined at the factory, and every hole through the face is permanent and visible.

A replacement part with the same silhouette but different centres forces new holes beside the old ones. The old holes then have to be plugged, and on a dark or patterned laminate a plug rarely disappears.

This is why like-for-like replacement is specified from the hole pattern rather than from a photograph, and why a kit that matches an existing system is worth more than a cheaper one that nearly does.

It can, but the mismatch shows. Satin stainless, polished stainless, matt black and anodised aluminium sit next to each other on a single door, and a new latch in a different finish reads as a repair rather than part of the design.

There is a practical dimension too. Finishes differ in how they cope with chlorinated cleaners and repeated wiping, so mixing them puts parts with different maintenance needs on the same door.

Where a full match is not available, keeping the mismatch consistent helps: replacing every latch in the washroom rather than one gives a deliberate result instead of a patched one.

The alloy and the fasteners. A kit intended for a shower block or a pool surround uses austenitic stainless in the 304 or 316 range throughout, including the screws, rather than a stainless face over a zinc-plated core.

Look for solid rather than plated components, nylon or acetal bushes at the pivots instead of bare steel, and captive fasteners that will not be dropped into standing water during service.

Chloride exposure is the deciding factor rather than humidity alone. Pool atmospheres and heavily chlorinated cleaning regimes attack the lower grades, which is why the specification for a leisure centre differs from an office.