LAST UPDATED: 4 September 2026
If water is starting to escape from the side of your shower door, or the old clear seal has warped, split or come loose, you may need a new vertical shower door seal, sometimes simply called a side shower door seal.
A lot of clear seals look similar from the front, but they can be used in very different places. The seal between two sliding glass panels may be nothing like the one used on a closing edge, hinge side, wall edge or folding section.
At SIMBA Seals UK, when we help customers match replacement seals, we usually start with the door layout and the position of the seal. Glass thickness and the gap come next.
That is the approach used in this guide.
Do You Actually Need a Vertical Shower Door Seal?
A vertical seal normally runs along the upright edge of the glass. It may cover a gap at the side of the door, between two glass panels, or between the glass and a wall or frame.
If water is mainly escaping underneath the glass, the bottom seal is usually the first place to check instead.
If the problem is on a vertical edge, do not worry about the profile name yet. First work out where the seal is fitted.
Which Vertical Shower Door Seal Suits Each Position?
Once you know the problem is on a vertical edge, look at the gap the seal is actually dealing with.
Different positions tend to suit different profiles. The images below show the main seal shapes in each situation so you can compare them with the relevant vertical seal ranges.
Between Two Sliding Glass Panels
For two sliding glass panels, F-shape vertical seals are often a useful place to start.
A single F-shape seal can be fitted to one glass edge, with the soft fin reaching across the gap between the panels.
Where the layout allows, you can also fit one to each facing glass edge. The fins may lightly touch the opposite glass, or overlap each other.
The main things to check are simple: does the fin cover the gap, can the glass still slide freely, and does the channel suit the glass thickness?
With two seals, the fins do not need to line up exactly. They just need enough combined coverage to cover the gap between the panels.
You can compare our F & H shape shower door seals.
Where Two Glass Panels Meet When the Door Closes
If two vertical glass edges meet when the door closes, magnetic shower door seals are worth checking first.
This can happen on sliding, hinged or pivot doors. The important part is not the name of the door, but how the two glass edges meet when it closes.
If there is a magnetic seal that suits the glass thickness, gap and closing arrangement, that would usually be the first option to consider.
If the magnetic sizes or closing style do not suit, a vertical shower door seal may still work instead. Bubble, HH and H-shape profiles are some of the options.
If you still have the old seal, keep it as a reference. It does not always need to be copied exactly. If it is missing, you can still work from the current gap, glass thickness and the way the two panels meet.
Where Two Glass Panels Are Connected by Hinges
On some hinged shower doors, the handle is on one side while the opposite edge is connected by hinges to a fixed glass panel. The moving door swings around this hinge edge whenever you open or close it.
This joint may also need a vertical seal between the moving door and the fixed panel.
If the moving and fixed glass sit roughly in a 180° straight line at the hinge, bubble, HH, H-shape or a suitable frameless folding seal may all be worth considering. The final choice comes down to the actual gap and glass thickness.
If the two glass panels form a 90° corner at the hinge, and one of them needs to move, a Y-shape or bubble seal is usually a better place to start.
If the glass also meets at 90° but both panels are fixed, a corner seal is generally more suitable. This type of rigid PVC profile is intended for a fixed glass corner and does not need to flex with a moving door.
Between the Glass and a Wall or Frame
If the vertical seal sits between the glass and a wall or frame, first check whether there is a hidden magnetic strip inside the fixed track.
Some magnets sit inside an aluminium frame or channel and do not run the full height of the door.
So if you cannot feel a magnet near the top of the frame, that does not necessarily mean there is not one further down inside.
A simple way to check is to hold a small piece of magnetic strip against different parts of the frame. If you can feel clear attraction or repulsion, there is likely to be a magnetic component inside. In that case, look for a matching magnetic seal first.
If there is no sign of a magnet and the other side is simply a wall or frame, a Y-shape, bubble or another flexible vertical seal may be more suitable. Then it comes down to the glass thickness and the gap you need to cover.
Vertical Seals on Folding and Bifold Doors
With folding or bifold shower doors, it helps to separate frameless and framed designs first.
On a frameless folding door, the seal normally clips straight onto the glass edge. A purpose-made folding shower door seal is usually the first type to consider.
Where the gap between the panels is quite small, for example below about 5mm, an HH-shape profile may also suit some layouts. One limitation is that some HH profiles work better with one main folding direction, so it is worth thinking about which way you normally open the door.
Framed folding doors are different.
The seal is often hidden inside an aluminium frame or track, so the profiles you can use are limited by the track width, slot size and internal shape.
In this case, open the top cover of the folding door and look at the old seal, how it sits in the track and the approximate size of the slot. Then look for a replacement with a similar fitting arrangement.
There are usually fewer replacement options for framed folding doors because the seal has to fit the original channel or track.
Still Have the Old Seal? Look at the End Profile
If you still have the old seal, keep it for now.
Looking at the end of it is usually much more useful than looking at it from the front. You can often see whether it has a single fin, two fins, a bubble section or a magnetic strip, and whether it clips onto the glass or fits into a frame or track.
The replacement does not always need to be identical to the old seal.
The old profile is mainly useful for ruling out shapes that clearly will not fit.
If the seal is badly worn, broken or no longer available, that is not necessarily a problem. Once you know the door layout and fitting position, the glass thickness and gap can still help narrow the options down.
Check the Glass Thickness, Vertical Gap and Contact Point
Once you have a rough idea of the profile you need, check the dimensions.
For a vertical seal that clips directly onto the glass, start with the thickness of the glass itself.
The rigid channel needs to suit that thickness. If it is too loose, the seal may not stay in place properly. Too tight, and it may be difficult to fit.
Measure the bare glass where possible, without including the old seal or anything wrapped around the edge.
If you are not sure where to measure, our shower screen seal measuring guide explains it in more detail.
Next, look at the vertical gap.
Close the door and see what the flexible part of the seal needs to reach. It may be another glass panel, another seal, a wall, a frame or a magnetic profile.
What matters is whether the soft part can reach across that distance without getting in the way when the door slides, swings or closes.
Check near the top, middle and bottom rather than measuring at one point only.
A fairly even gap makes things much easier. If it changes noticeably from top to bottom, though, there is one more thing to check.
What If the Gap Is Different at the Top and Bottom?
A gap that changes from top to bottom does not automatically mean the shower door needs repairing.
Flexible vertical seals such as HH, bubble or Y-shape profiles can often accommodate some variation in the gap. If the flexible part still covers the required area all the way down without affecting the way the door opens and closes, they may still work well.
Magnetic seals are less forgiving when the gap changes significantly. The two magnetic edges need to meet reasonably consistently, so a seal that catches at one point but stays apart somewhere else may not work particularly well.
Before arranging a repair, it is worth checking whether a different flexible profile could handle the gap, or whether the profile itself can be trimmed to suit the changing space.
We have also put together some alternative sealing ideas and adjustment options in our misaligned shower door help guide.
If those approaches still leave part of the gap uncovered, or the two glass edges are clearly no longer parallel, it may then be worth looking at the door alignment and, if needed, getting someone to adjust it.
Magnetic Seal or Standard Vertical Seal: Which Should You Choose?
If both a magnetic seal and a standard vertical seal could work in the same position, we would usually look at the magnetic option first.
That is particularly true when the original magnetic seal has always closed reliably, the door works properly and a similar replacement is easy to obtain. In that situation, staying with a magnetic seal is often the simplest option and keeps the original closing arrangement.
Two frameless folding doors, for example, can also use a magnetic seal between them, provided the gap and alignment are suitable.
Magnetic seals do rely more heavily on a consistent gap and reasonably good alignment.
We also see doors where the old magnets only just catch, the top and bottom gaps are quite different, or finding the same replacement each time becomes difficult.
In that situation, there may be little benefit in insisting on another magnetic profile.
An HH, bubble, Y-shape or another flexible vertical seal may be a more practical alternative. These profiles can often cope with a little more variation in the gap and give you more choice when matching a replacement.
A simple way to think about it is this:
If the magnetic setup has always worked well and replacements are easy to find, it makes sense to stay with it.
If the magnetic closure has always been marginal, or finding a replacement is becoming difficult, a standard vertical seal may be the easier option.
When Might a New Vertical Seal Not Be Enough?
Some problems look like seal problems but may involve the door itself.
If the door is visibly leaning or dropping, the top and bottom gaps are very different, the leak is concentrated around the hinge, or the aluminium frame or channel has been damaged, replacing the PVC seal alone may not solve everything.
The same applies if a new seal makes the door noticeably harder to open or close. That can be a sign that the profile does not suit the way the door moves, rather than simply needing a longer or wider seal.
Working out whether the issue is the seal or the door structure first can save a lot of trial and error.
One Last Check Before Ordering
By this point, you do not need to remember the name of every profile.
If you know where the seal fits, how the door moves, roughly what the old profile looks like, the glass thickness and the gap it needs to cover, you already have enough information to start comparing products.
At this stage, the product photos, glass thickness and gap figures should make much more sense than they did at the beginning.
Chosen Your Seal? Fitting Comes Next
Once the profile, glass thickness and gap are sorted, you can move on to fitting.
Things such as how long to cut the seal, which way the fin should face, how to remove the old strip and how to fit the new one all belong to that next stage.
If you are ready to replace it, see our how to replace vertical shower door seal guide.
Keeping selection and fitting as two separate jobs usually makes the whole process easier to follow.
Still Not Sure Which Vertical Shower Door Seal You Need?
Some older shower doors have unusual layouts, and sometimes product photos alone are not enough to identify the right seal.
If you are still unsure, sending us a couple of photos is usually the easiest next step.
Take one clear photo of the whole shower door or screen, then another close-up of the end profile of the old seal.
If the old seal is too worn to make out, photograph the area you are trying to seal instead.
Send the photos to us on WhatsApp, together with the glass thickness and an approximate vertical gap.
The full-door photo helps us understand the layout and where the seal fits. The end-profile photo helps us see what type of seal was originally used.
The SIMBA Seals UK team can then help narrow down the replacement profiles that are more likely to suit your door.
If you already know the dimensions and layout, you can also go straight to our vertical shower door seal range and compare the options yourself.