Last updated: 28 July 2026
When replacing a magnetic shower door seal, you do not need to find one that looks exactly like the old seal.
What matters more is where it fits, how the glass panels meet when the door closes, and whether the glass thickness and closing gap are suitable. If these points match, a slightly different outer shape may still work.
Is the old seal actually magnetic?
Magnetic seals are normally fitted along the closing edge of a shower door.
Close the door slowly and watch what happens as the two seals come together. If they pull towards each other and help hold the door shut, they are likely to be magnetic.
Not every seal fitted along the side of a shower door contains a magnet.
Where two sliding glass panels overlap, for example, the seal is often a water deflector with a soft fin. A seal beside a frame or track may simply act as a buffer or water barrier. A firm section inside the profile does not always mean it is magnetic.
The simplest check is to see whether the old seal needs to meet and attract another seal when the door closes. If the two sides pull together, it is usually a magnetic closing seal.
How do the glass panels meet when the door closes?
Close the shower door fully and look at the position of the two glass panels.
If they sit in one straight line, the door has a 180° closure. This is common where two doors meet in the middle, or where a moving door closes in line with a fixed glass panel.
Not all 180° magnetic seals have the same profile. On some shower doors, the glass panels do not sit in the same plane when closed. The magnetic sections therefore need to be offset so that they can meet. These doors usually need an offset seal rather than a standard 180° pair.
If the moving door closes against a fixed side panel at a right angle, this is a 90° closure.
If the two panels meet at a wider angle, it may be a 135° closure. This arrangement needs a seal made for 135° glass, rather than a 90° or 180° product.
Some products are described as a 45-degree magnetic shower door seal. Here, 45° refers to the position of the magnetic section inside the seal. It does not describe the angle between the two glass panels.
A 45° magnetic edge is commonly used for 180° or 90° closures, but not for a 135° arrangement.
Start with the closing angle, then compare the seal profile. The outer shape of the old seal on its own is not enough.
Is the old seal push-on or self-adhesive?
Most magnetic shower door seals are push-on profiles. They fit directly over an exposed glass edge and do not need tape or glue.
The channel must suit the glass thickness. When the size is correct, the seal should stay in place during normal use.
A smaller number of shower doors use self-adhesive magnetic seals. These are fixed to the surface of the glass or frame rather than pushed over the glass edge. Their performance depends more on the condition of the fitting surface and the amount of movement or impact they receive.
Do not choose a self-adhesive seal simply because it looks easier to fit. For a straightforward replacement, it is usually best to keep the same fitting method as the original seal.
Whether a push-on or self-adhesive shower door seal is suitable depends on whether the glass edge is exposed, how the old seal was fitted and whether the surface can hold an adhesive strip.
Should you measure the glass or the frame channel?
The correct measurement depends on whether the old magnetic seal clips onto the glass or fits inside a frame channel.
How to measure a frameless shower door seal
On a frameless shower door, the magnetic seal normally fits over the exposed edge of the glass.
The important measurement is the glass itself, usually 6mm, 8mm or 10mm. Do not measure the outside width of the channel on the old seal.
An older profile may have worn or changed shape. Different products can also have different outer dimensions while fitting the same glass thickness.
If the old seal is still in place and the glass thickness is difficult to check, how to measure shower door glass thickness covers the measurements that can be taken before removing it.
How to measure a framed shower door seal
A magnetic seal on a framed shower door is often pushed into an aluminium frame or track rather than clipped over the glass. In this case, the glass thickness alone is not enough to identify the right product.
For T-shaped profiles, our framed shower door magnetic strip guide explains how to check whether the fixing section suits the track and whether the magnetic edge will reach the correct closing position.
Start by removing a short piece of the old seal. Measure the section that fits into the frame and compare its cross-section, width and magnetic position.
Measuring the old insert is often easier than trying to measure a narrow channel inside the frame.
An older seal may have shrunk, worn down or changed shape. A measurement that does not exactly match a current product does not always mean that no replacement is available.
In this situation, send SIMBA:
- a clear photo of the end profile;
- a photo showing where the seal fits;
- the width of the section that pushes into the frame; and
- a front view of the shower door while it is closed.
If this is still not enough to identify the seal, we may ask you to measure the frame opening and the inside of the channel.
How should the closing gap be measured?
The closing gap is the distance between the two glass edges when the shower door is in its normal closed position. This is the space that the pair of magnetic seals need to bridge.
Close the door as you normally would. Do not push it further shut by hand.
Measure the gap near the top, middle and bottom. At the same time, check whether the two glass edges are roughly parallel. A door that sits slightly out of line can have a different gap at each point, so measuring only the top or bottom may not give the full picture.
Measure the distance between the glass edges with the door closed. Do not measure:
- the space when the door is open;
- the overall width of the old seal;
- the overlap between sliding glass panels; or
- the full width of the track.
180° sliding doors
Magnetic seals for 180° sliding doors are often described by their maximum working gap, such as 19mm or 22mm.
This does not mean the glass panels must be exactly 19mm or 22mm apart.
On many sliding shower doors, the closing position can be adjusted along the track so that the two magnetic sections meet correctly.
For example, a seal with a maximum working gap of 22mm may also work with a smaller gap, provided the doors can be positioned so that the magnetic edges meet properly.
90° shower doors
A 90° magnetic seal is normally used where a moving door closes against a fixed side panel at a right angle.
First check that the two glass panels meet at roughly 90° in their normal closed position. Then measure the gap at the points shown on the product drawing.
The measurements do not have to be exact, but they should be reasonably close to the recommended range.
Unlike sliding doors, hinged and pivot doors have a more fixed closing position, so there is much less scope to make up for a larger difference.
135° shower doors
With a 135° magnetic seal, the nearest point between the two glass panels does not tell the whole story.
Use the product drawing and compare both the inner and outer measuring points. Both measurements should be reasonably close to those shown on the drawing before the magnetic sections are likely to meet correctly.
For fixed 90° and 135° closures, the maximum working gap is only part of the check. The closing angle, measuring points and actual distance all need to match.
If the difference is too great, the seals may fit onto the glass but still fail to meet evenly when the door is closed.
Can a magnetic seal help with a slightly misaligned shower door?
Sometimes the two glass panels are still roughly parallel, but the magnetic sections do not meet evenly from top to bottom.
The top may pull together while a small gap remains at the bottom. In other cases, the door only closes fully after being pushed by hand.
A standard seal with a fully rigid PVC profile is not always the best option for this type of small misalignment.
Some magnetic seals have a softer outer covering around the magnetic section. This allows it to move slightly and follow the actual closing position more easily.
Compared with a fully rigid profile, the softer section can cope better with small differences between the top, middle and bottom of the door.
You still need to check the glass thickness, closing angle and approximate gap. A flexible section can help the magnetic faces meet, but it cannot correct a badly leaning door, worn hinges or a track that has moved.
If the glass panels are clearly out of line from top to bottom, the door itself should be adjusted first.
A flexible magnetic seal can help with a slightly misaligned shower door where the panels remain roughly parallel but the closing gap varies slightly from top to bottom.
Can a folding shower door still use a magnetic seal?
Yes, but choosing the right one is usually less straightforward than it is for a standard shower door.
On many 180° sliding doors, the closing position can be adjusted along the track. Many magnetic seals are therefore designed to work within a common maximum gap.
If the glass thickness, magnetic profile and working gap all match, they are usually easier to position correctly.
Folding doors are different.
The panel widths, hinge positions and closing action can vary from one manufacturer to another. The distance between the glass panels when the door is closed is not standard.
Because of this, the same magnetic seal may work perfectly on one folding door but sit too far away on another. In some cases, the magnetic sections may not meet at all.
If the closing gap does not suit a standard magnetic seal, there may be another solution.
Some folding doors use flexible joining seals, frame-channel seals or other alternatives to magnetic seals, depending on how the door closes.
A new seal does not need to match every outside measurement
A replacement magnetic seal does not need to have exactly the same outer profile as the old one.
Different manufacturers use different channel shapes, clear PVC sections and magnetic positions. Two seals can look different and still suit the same shower door.
The main points to match are:
- the glass thickness on both sides;
- the fitting method;
- how the glass panels meet when the door closes;
- whether the two magnetic sections line up or sit slightly offset; and
- whether the closing gap falls within the product’s working range.
The seal also needs to be long enough to cover the full glass edge. A longer length can normally be cut down, but a seal that is too short will leave part of the closing edge uncovered.
The exact width of the clear PVC, every outside measurement and the original brand are usually less important.
An older seal may also have worn, shrunk or changed shape, so its current appearance may not show the original dimensions accurately.
If the replacement fits the glass or frame correctly and both sides meet when the door closes, the outside shape does not need to be identical.
Can you replace only one side?
Magnetic shower door seals work as a pair.
Before buying, check both sides rather than looking only at the seal that is damaged or missing. The other side may also be worn, loose or no longer pulling evenly.
If you replace one side only, the new and old magnetic sections may sit in different positions or face in different directions. The profile shapes may also differ.
Both seals may fit onto the glass, but only part of the length may pull together. In some cases, they may not attract at all.
If the other side is already showing signs that the magnetic shower door seal is no longer working, replacing both sides is usually the safer option.
If you plan to keep one of the old seals, make sure it can work with the replacement.
Final checks before buying
Before choosing a product, confirm:
- whether the glass closes at 180°, 90° or 135°;
- whether the seal clips onto the glass, sticks to a surface or fits into a frame channel;
- the glass thickness, or the frame-channel size on a framed door;
- the actual gap when the door is resting in its normal closed position;
- whether the two magnetic sections line up or sit offset;
- whether you are replacing one side or both; and
- whether the seal is long enough to cover the full glass edge.
Once these points are clear, you can compare suitable products in the magnetic shower door seal range.
For framed doors, folding doors or magnetic positions that are difficult to identify, send SIMBA a clear photo of the end profile, the fitting position and the front of the shower door while it is closed.