Shower Seal Fit Fit by the numbers

Shower Door Glossary

Every term a seal listing, install manual, or glass shop can throw at you — defined in plain English with the numbers that matter. Terms link into the full guides where one exists.

Sweep (door sweep) full guide →
The flexible strip — usually clear PVC — along the bottom edge of a shower door that closes the gap to the curb or threshold. Most carry one or two fins plus a drip deflector, and it is the most frequently replaced shower door part (typically every 2–5 years).
Drip rail full guide →
A rigid horizontal profile (aluminum or polycarbonate) on the outside face of the door bottom that catches water sheeting down the glass and directs it back into the shower. Many carry a replaceable tapered vinyl insert.
Wipe / drip fin
The soft angled blade on a sweep or seal that lightly contacts the threshold or adjacent glass. It installs pointing into the shower so water pressure presses it tighter; size it about 1/8–1/4″ taller than the measured gap.
Bulb seal full guide →
A seal with a hollow round cross-section that compresses against a wall or jamb to close variable gaps. Used vertically on hinge and wall sides; not recommended under the door bottom, where it drags and traps limescale.
H-seal (h-jamb) full guide →
An H-shaped profile that slides over one glass edge and presents a sealing flange to a neighboring panel — the standard answer for 180° glass-to-glass gaps of about 3/16–1/2″.
F-seal
A profile shaped like the letter F used where sliding bypass panels overlap: one leg grips the glass edge while the flange wipes the passing panel.
Jamb (wall / strike)
The vertical member at the side of a door opening. The wall jamb is the aluminum vertical fixed to the wall (usually with about ±1″ of adjustment); the strike jamb is what the door closes against, often carrying latch vinyl or a magnet strip.
Header-free (open-top) enclosure
A frameless design with no top rail. Industry guidance requires a 1/2″ fixed panel no wider than 22″, heavy L-brackets matching the hinge count, and a door under 30″ wide — and advises against hinging off 90° return panels.
Support bar
A slim tube bracing a tall frameless fixed panel to the wall or ceiling — the minimal alternative to a full header.
Curb
The raised step the enclosure sits on. US code (IRC P2709.1) puts the finished curb top 2–9″ above the drain; installers slope it about 1/4″ per foot inward, which is why bottom gaps differ end to end.
Threshold / water dam full guide →
The horizontal member or strip at floor level under the door — an aluminum track on framed kits, or a surface-mounted dam strip that raises the sill so a standard sweep can reach.
Weep hole
Small (~1/8″) drain openings on the inside face of a framed bottom track that let trapped water drain back into the shower. Clogged or caulked-over weep holes are a leading cause of "mystery" slider leaks — never seal them.
Bottom track full guide →
The channel on the curb or tub rim of framed sliders that locates the panels. It carries no door weight, is bedded in silicone underneath, and is cut about 1/4″ short of the opening for jamb fit-up.
Bypass door full guide →
A two-panel sliding system whose panels pass each other on parallel tracks, carrying 4–8 rollers, a center bottom guide, and vertical overlap seals.
Roller (runner) full guide →
The wheeled carriage that hangs a sliding panel from the header. Wheel diameter (commonly 3/4″ or 7/8″), edge profile, and bracket style identify the replacement; service life runs about 5–8 years.
Anti-jump clip
Hardware inside the header that stops rollers lifting out of the track. A common adjustment: run the screw to contact, then back it off half a turn so panels glide but cannot derail.
Bottom guide full guide →
The small plastic fitting on the curb centerline that keeps bypass panels aligned without carrying weight. A missing guide lets doors swing and derail.
Glazing vinyl
The vinyl strip packed between glass and metal frame extrusions on framed doors. Replaceable when panels rattle or leak inside the frame.
Wedge gasket
The hard strip tapped into a U-channel's outer face to lock glass mechanically in dry-glaze systems, paired with a soft L-gasket inside — no structural silicone needed in the channel.
Setting block
Small vinyl blocks (commonly 1/8″ thick) placed under glass in channels and clamps — at least two per panel — to support the weight and set the reveal.
Glass clamp
A screw-fixed metal fitting that captures a fixed panel edge between gasketed faces. One clamp suffices up to roughly 12″-wide panels; gaskets keep metal off glass.
Magnetic profile full guide →
A co-extruded PVC seal with an embedded flexible ferrite magnet strip, made in 180°, 135° and 90° closing geometries for 4–12 mm glass. Always replaced in polarity-matched pairs; the PVC fails long before the magnet does.
Dual durometer (co-extrusion)
Manufacturing a seal from two hardnesses in one pass: a rigid carrier that snaps onto the glass fused to a soft sealing lip. "Durometer" is the Shore hardness rating — flexible seal PVC runs about Shore A 70–80.
Plasticizer
The additive that keeps PVC flexible. Heat, UV and harsh cleaners leach it out over time, which is why old sweeps shrink, yellow and turn brittle — chemical aging that no cleaner reverses.
Polycarbonate
The rigid, glass-clear plastic used for seal carriers, jamb profiles and drip rail bodies. Stiffer and far more yellowing-resistant than PVC; cut it with a fine-tooth saw — scoring and snapping shatters it.
Tempered glass
Safety glass heat-treated above ~600 °C and quenched, about 4× stronger than annealed glass. US law (CPSC 16 CFR 1201 / ANSI Z97.1) requires it in shower doors; it shatters into small blunt granules and cannot be cut or drilled after tempering.
Heat-soak test (HST)
Factory screening (EN 14179: 290 °C for at least 2 hours) that forces panels with unstable nickel-sulfide inclusions to fail before installation — eliminating about 95% of spontaneous-breakage risk.
Out of plumb
A wall or panel that is not perfectly vertical. Kits tolerate limited out-of-plumb (commonly 3/8–1/2″ via adjustable jambs); beyond that, seals compress unevenly and doors drift open or will not latch.
Transom full guide →
The fixed or operable vent panel above a steam-shower door. Opening it after a session dries the cabin and protects the gaskets and grout from standing humidity.
Low-iron glass
Reduced-iron "ultra-clear" float glass without the green edge tint of standard glass — common on high-end frameless enclosures. Seals fit it exactly as they fit standard glass of the same thickness.