Usually yes, because bathroom openings are rarely the sizes stock doors are built to. Custom glass is cut to the walls you actually have, out of plumb and all. Accurate Glass & Mirror cuts and edges every panel in its own Lodi shop, so the door fits the room instead of the room being shimmed to fit the door.
Tiled openings are almost never square. A wall bows in the middle, tile runs a little thicker at one end than the other, the curb was floated by hand, and the ceiling is not parallel to the floor. A stock door assumes a rectangle and hands you an adjustable jamb to swallow the difference, which works right up until the difference is bigger than the jamb.
Custom fabrication starts from the opposite end. The opening gets measured at the top, the middle and the bottom, the out of square is written down, and the glass is cut to those numbers before it is tempered. Hinge and clip positions are set for where the studs and blocking actually sit rather than where a catalog assumed they would be.
Stock sizes arrive in fixed increments with a limited adjustment range, so a handful of situations put them out of reach quickly. An opening that falls between sizes. A ceiling tall enough to want a transom above the door. A neo angle or corner layout with two glass legs meeting at a post. A tub deck with a rolled rim that the glass has to land on. Any steam room, which has to run to the ceiling and seal. Push a stock unit into one of those and you get a gap at the wall, a door that binds against its jamb, or a filler strip doing work it was never meant to do.
If the alcove measures close to a common width, the walls sit within a small fraction of plumb, the tile is new and flat, and a framed look suits the room, a stock door is a fair buy and nobody at a glass shop should talk you out of it. The difference simply will not be visible.
Custom earns its keep on odd geometry, on heavy frameless glass that has to be anchored precisely, and on hardware that stays tight for the life of the bathroom rather than loosening after a few seasons. It also earns it on resale appeal, since a door that meets the tile cleanly at every edge reads as part of the room and a door with a shim gap reads as an afterthought.
Because the glass is tempered. Heat treating locks the panel into a stressed state, and any cut, drill or notch afterward shatters it into pebbles. Every edge, hinge cutout and hardware hole has to be finished before the glass goes into the oven, which is exactly why the opening is measured first and the panel is cut to those numbers.
Usually, yes. Panels are measured against the finished tile and the hardware anchors through it into the framing behind. What matters is that the tile is sound and well bonded, since a hollow spot under an anchor point will not hold a hinge carrying heavy glass. That is one reason a shop measures after the tile is set, not before.
Bring the room to the Lodi showroom on Industrial Road, where full enclosures are set up to walk through and the glass and finish wall lets you hold polished chrome next to matte black. Residential measures are free, and nothing gets cut until someone has stood in your bathroom.
