How to Choose the Right Shower Door Bottom Seal

Choosing the right shower door bottom seal depends on more than glass thickness. The gap beneath the door, the shape of the seal and how the door closes all affect which replacement will fit.

We've helped customers whose new seals grip the glass but still leak, drag against the shower tray or leave a gap at one end. A seal that looks right in a product photo isn't always the right fit.

This page brings together our practical guides to shower door bottom seals, covering measurements, seal types, fin lengths, fitting and common problems. Pick the topic that matches your door and follow the relevant guide for more detail.

Already know your glass thickness and bottom gap? You can browse our replacement shower door bottom seals.

First, What Problem Are You Trying to Fix?

Most people do not begin with a technical seal name. They begin with a problem.

Use the table below to find the most useful next step.

If none of these quite matches your situation, continue with the buying steps below.

Step 1: Check Whether You Need a Bottom Seal

Water on the bathroom floor doesn't always mean the bottom seal needs replacing. It may be running down from a hinge, side gap or frame joint before reaching the bottom corner.

Dry the area and check where the water first appears. Water escaping directly beneath the glass may point to a missing, worn or unsuitable bottom seal.

A leak starting at the hinge, side edge or tray joint may need a different solution. Our guide to shower door leaks at the bottom explains why and what to check before ordering a replacement.

Step 2: Measure the Glass Thickness

The seal needs to grip the glass securely. Common shower glass thicknesses include 4mm, 6mm, 8mm and 10mm, and a seal designed for one size may not fit another properly.

Measure the bare glass rather than the old plastic seal, which may have changed shape over time. Our guide to measuring a shower screen seal explains how to check the thickness before choosing a replacement.

Step 3: Measure the Gap Under the Door

The bottom gap is the space between the lower edge of the glass and the shower tray or bath rim. It helps determine how far the seal's fin needs to extend.

Check the gap at both ends and in the middle with the door closed. A fin that's too short may leave an opening, while one that's too long can fold or drag against the tray.

Where the gap varies noticeably, choosing the longest fin isn't necessarily the answer.

Choosing a Bottom Seal for Different Shower Doors

Start with the way your shower door opens. Two doors can have the same glass thickness and bottom gap but need quite different seals. A hinged door may have plenty of room for a fin underneath, while a sliding door could have a track or guide block in the way.

Hinged and Pivot Shower Doors

For a glass door that swings open, a push-on bottom seal is often a good starting point. Depending on the gap, you might need a single fin, twin fins or a profile with a drip deflector to guide water back into the shower.

Have a look at how the fin sits when the door is closed. It needs to cover the gap without being pushed too firmly against the tray.

We've seen customers fit a fin that's much longer than the gap beneath their door. It bends against the tray and can leave a small opening near the hinge, letting water through.

Door movement and the space around the hinge also matter when choosing seals for a hinged shower door, particularly where the bottom and side seals meet.

Sliding Shower Doors

Sliding doors can be a little trickier around the bottom edge. Rollers, tracks and guide blocks sometimes leave very little room for a downward-facing fin.

A bottom seal with a side-facing fin may be more suitable for some designs. Adhesive seals are another option where there's a suitable surface and enough clearance. Check that nothing catches as the door slides.

The seals between overlapping glass panels and where the doors close do different jobs. Knowing which seal goes where on a sliding shower door can save you ordering a replacement for the wrong part of the door.

Curved Bath Screens

A seal can grip the glass securely and still leave a gap if it doesn't follow the curve of a bath screen.

Some straight seals are too rigid to bend neatly around the lower edge. They may lift in places, even if the glass thickness is correct.

With a P-shaped bath screen, check the curve as well as the glass thickness and the gap above the bath rim. Not every curved screen takes the same bottom seal.

Folding and Framed Shower Doors

Before ordering a replacement for a folding or framed door, have a look at how the old seal is held in place.

Some frameless folding doors use push-on seals along the bottom of the glass. The fin still needs room to move when the panels fold.

Framed doors can be quite different. The seal may slide into a metal channel or use a shaped fixing edge rather than grip the glass directly. Glass thickness alone won't tell you which one fits.

Our guide to folding shower door seals also covers the seals between folding panels and inside the frame, which can look quite different from a standard bottom seal.

Very Small Bottom Gaps and Unusual Seal Shapes

Some shower doors sit so close to the tray that there's barely room for a fin underneath. A deep seal may drag across the tray and make the door difficult to open or close.

A slimmer profile or side-facing fin may be worth considering. Some doors also rely on a threshold strip to help keep water inside. There's the fitting space to think about too, especially when there's not enough room to push a new seal onto the glass.

You might also find that your old seal has a rounded bulb instead of a flat fin.

Bulb seals are often used along vertical edges where two surfaces press together. Some designs can be used at the bottom, but a bulb pressed constantly against the tray may cause friction, make the door harder to move or leave gaps elsewhere. We've covered the problems with fitting bulb seals along the bottom of a shower door separately.

If you're still unsure what type you have, a clear photo of the end of the old seal is usually more useful than trying to match it by appearance alone.

Common Buying Mistakes to Avoid

It's easy to order a seal that looks right in a photo but doesn't quite fit your door.

The usual problems are choosing by the shape of an old, worn seal, buying the wrong channel size or picking a fin that's too long for the gap. Some seals also need room to move around hinges, tracks or brackets.

Fit the New Seal the Correct Way Round

Once you have the right seal, fitting direction still matters.

Clean the bottom edge of the glass before installing the new strip. Limescale, old soap and residue can stop the channel from gripping properly.

Push the seal on evenly along the full width of the door. It should sit straight, without twisting or bulging.

If the seal has a drip rail, the water-deflecting lip normally needs to face back into the shower tray.

If you are unsure, read which way round a shower screen seal should go before cutting the seal to its final length.

If this is your first time replacing one, see our step-by-step guide on how to replace a shower door bottom seal before fitting the new strip.

Why Seal Quality Matters

Two clear shower door seals can look almost identical when new. The difference often becomes noticeable after regular use.

A bottom seal is exposed to water, daily movement, limescale and cleaning products. Cheaper materials may turn yellow, become brittle or lose their flexibility sooner, leaving the seal looking worn and less able to keep water inside the shower.

A well-made seal should hold its shape, stay flexible and resist premature yellowing and cracking. That means a longer useful life, fewer replacements and a cleaner-looking shower door.

The material and construction both make a difference. We've covered what to look for in our shower seal strip quality guide.

Ready to Choose a Replacement?

By this point, you should have a better idea of which type of bottom seal your door needs.

Have your glass thickness and bottom gap measurements handy. In our shower door bottom seals collection, you can compare different profiles and check the recommended glass thickness and gap range for each one.

Look closely at the end profile, especially the direction and length of the fin. A seal that fits the glass still needs enough room to work properly when the door closes.

Not sure which one matches your old seal? Send us a clear photo of its end, along with your measurements. We'd rather help you check before you order than have you buy another seal that doesn't fit.