Which shower screen seal do you need?

“Which shower door seal” and “which shower screen seal” are two of the most common seal questions people type into Google, usually after noticing a puddle on the bathroom floor or a strip of yellow plastic that no longer looks clean. Seals are cheap, push-fit and easy to replace. The hard part is buying the right one, because they are sold by glass thickness, gap size and profile, and a seal that is nearly right is no better than no seal.

This guide covers the common seal types, how to measure for one, when to replace rather than clean, and how to fit the new one.

What do shower screen seals actually do?

A frameless or semi-frameless shower screen is not sealed to the tray or the walls with silicone along every edge. There are deliberate small gaps around the glass so it can move slightly and so it never touches tile, metal or another pane, which matters for the reasons in our guide on why shower screens shatter. Seals close those gaps with something soft. They also stop a door banging against a fixed panel and cushion the glass when the door is pulled shut.

That is why seals wear out and glass does not. The seal takes the water, the limescale, the bathroom cleaner and the knocks, and after a few years it stiffens, yellows and stops closing the gap.

Which types of shower screen seal are there?

Most seals fall into a handful of profiles. Shops use slightly different names, so look at the shape rather than the label.

• Bottom seal, drip seal or deflector. Pushes onto the bottom edge of a door or panel. It has a lip that angles down and inwards so water running down the glass is turned back into the tray instead of dripping over the edge. This is the seal that stops most leaks.
• Bubble or bulb seal. A rounded hollow tube along one edge. Fitted to the closing edge of a hinged door, it squashes against the fixed panel or wall profile to close the gap and soften the closing action.
• Fin or blade seal. A flat, flexible flap instead of a bubble. Does the same job where the gap is small and even.
• Magnetic seal. Two strips, one on the door and one on the panel or frame, with magnets inside that pull the door shut and hold it closed. They are sold as a pair and come in 90 degree and 180 degree versions depending on whether the door meets the panel at a corner or in line.
• Glass to wall seal. A profile that sits in the gap between a fixed panel and a wall or tiled surface, used where the glass is held in clamps rather than a full-height channel.
• Panel to panel seal. A slim profile that bridges two fixed panels meeting in line or at a corner.

Framed enclosures are different. Their seals are usually specific to the frame profile, so for a framed door the manufacturer’s own part is the safe choice, and the model number on the frame is the first thing to find.

How do you measure for a shower screen seal?

Three measurements decide which seal you need.

1. Glass thickness

Shower glass is normally 4mm, 5mm or 6mm on framed enclosures, 6mm or 8mm on semi-frameless screens and 8mm or 10mm on frameless doors and panels. The seal grips the glass by its thickness, so this number has to be exact. Measure an exposed edge with a steel rule or callipers, or check the paperwork from when the screen was bought. Our thickness guide explains which thickness is used where.

Made-to-measure frameless screens are normally at the thick end. Lumelle Glass, for example, uses 10mm clear toughened glass with flat polished edges as standard, so a seal for one of its doors needs to be a 10mm profile, not a 6mm or 8mm one that happens to look similar.

2. The gap

Measure the gap the seal has to close: between the bottom of the door and the tray, between the door edge and the fixed panel, or between the glass and the wall. Measure at both ends and in the middle, because glass and trays are rarely perfectly parallel. Seals are made with lips and bubbles of different lengths, and a lip that is too short leaves the leak, while one that is too long drags on the tray and curls up.

If the gap on a hinged door is wider at the bottom than the top, or has grown over time, the door has probably dropped on its hinges. Adjust or tighten the hinges first, then measure. A new seal will not fix a door that is hanging crooked.

3. Length and position

Measure the edge the seal runs along, then buy a seal that is at least that long. Seals come in standard lengths and are cut down at home. Note where it goes, because a bottom seal on a door is a different profile from a side seal, even on the same door.

When should a seal be replaced rather than cleaned?

Try cleaning first. Pull the seal off, soak it in warm water with a little washing up liquid, scrub with a soft brush, and use white vinegar on any limescale. Avoid bleach and anything abrasive, which make the plastic brittle. Our cleaning guide covers the glass itself.

Replace the seal when:

• it has gone yellow or cloudy and will not come clean,
• it has hardened and no longer springs back when you press it,
• the lip or bubble is cracked, torn or has gone wavy,
• black mould has grown into the plastic rather than sitting on the surface,
• the shower leaks even though the seal looks intact, which usually means it has shrunk or stiffened and no longer closes the gap.

On a frameless screen the seals are the only parts that need replacing in normal use. The glass and good quality hinges should outlast several sets of seals.

How do you fit a new shower screen seal?

Most seals are push-fit, so there is no drilling or gluing. That is just as well, because toughened shower glass cannot be drilled, cut or altered once it is made, so everything that attaches to it after the fact has to clip on.

1. Remove the old seal and clean the glass edge thoroughly. Limescale and soap residue stop the new seal gripping.
2. Cut the new seal to length with sharp scissors or a fine saw, slightly over length at first. Cut square, and trim again once it is in place.
3. Warm the seal in a bowl of warm water for a few minutes. It becomes more flexible and slides on without kinking.
4. Push it on from one end, working along the edge. The lip on a bottom seal must face into the shower and angle downwards, so water is turned back into the tray.
5. Check the door still closes freely and that the seal does not snag on the tray, the panel or the hinges. Trim anything that catches.
6. Leave it to settle overnight before the first shower.

Do not run a bead of silicone along the inside bottom edge of the glass to stop a leak. It traps water against the glass and the tray, grows mould and is a nuisance to remove. The right bottom seal does the job without it.

Why does my shower door still leak?

If the new seal is on and water is still reaching the floor, work through these in order:

• Gap at the hinge side. Frameless hinged doors usually have a small open gap at the hinges and no seal there. A little water escaping here is normal, and the fix is the shower head position and the length of the glass, which we cover in our guide to how long a shower screen should be.
• Water running under the panel. A fixed panel usually has silicone along its outside edge where it meets the tray. If that silicone has failed, strip it out and re-seal the outside only.
• Door dropped on its hinges. Adjust the hinges so the gap is even top to bottom, then re-check the seal.

Buying checklist

Get those right and a replacement seal takes a few minutes to fit and should stop the leak for years. If the glass itself is damaged or the hinges have failed, that is a different job, and our frameless vs framed guide explains what to look for in a replacement screen.