How to Measure Shower Screen Seal?

Let’s face it — measuring a shower screen seal can feel tricky.

Is it the gap you measure? The thickness? The glass?

We get this question all the time.

It’s way easier than it sounds.

No fancy tools. No plumber needed.

In this quick guide, we’ll show you how to measure your shower screen seal properly — so you get the right fit the first time.

Let’s get started.

 

 

What do you need to get started?

You don’t need much — just a few simple tools:

• A tape measure or ruler
• A pen and paper (to jot down the numbers)
• A torch (if your bathroom lighting isn’t great)
• Your old seal (if you have it — useful for comparison)

 

 

What Type of Seal Do You Need?

Let’s be honest — most people buy the wrong shower seal simply because they’re not sure which type they need. Sound familiar?

You're not alone.

First, a quick reminder: What is a shower door sweep?

It’s that little strip of plastic or rubber that stops water from leaking out of your shower. Simple, but super important.

Now let’s break down the common types of frameless shower door seals you’ll find:

 

a. Bottom Seal

Fits along the bottom edge of the glass.

Keeps water from dripping onto your floor.

 

b. Vertical Seal

Runs up the side of the glass, usually where it meets a wall or another glass panel.

 

c. Magnetic Seal

Used on double doors. The magnets pull the doors together to form a tight seal.

 

d.Sliding Door Seal (F-Type Seal)

Found between two sliding glass panels. Fills the gap and stops leaks.

 

 

How to Measure for a Shower Door Bottom Seal

Once you know which part of the shower needs sealing, it’s time to measure the gap — that’s how you’ll pick the right size.

The bottom seal is one of the most commonly replaced parts.

If water’s leaking under your shower door, chances are it’s time for a new one.

Follow these simple steps to get it right:

 

1. Measure Your Glass Thickness

Measure the thickness of your shower screen.

Common options: 4mm / 6mm / 8mm / 10mm.

Why it matters: Pick the wrong one, and your seal will fall off or won’t go on.

To stay in place properly, the seal needs to grip the glass with enough friction — ideally over 50N. That’s the minimum required to keep it secure without slipping off.

Want proof? Check out how SIMBA products perform in our shower door seal quality testing— we test for grip, fit, and long-term durability.

2. Measure Your Gap Size

Measure the distance between the bottom of the glass and the highest point of your shower tray or threshold seal.

Getting the Right Height Matters

Too tall? Water leaks.

Too short? The edge folds.

Always double-check your measurements before you buy — it makes all the difference.

Please note: The bottom seal needs to be used in conjunction with the  threshold seals to ensure a perfect seal.

 

 

3.Measure Your Length of Shower Glass

Always buy a shower door seal longer than your glass length, just in case. You can trim it down at home (don’t worry, we’ve got a handy How to Cut a Shower Screen Seal guide to help!).

Since manual measurements aren’t always spot-on, it’s a good idea to trim your shower screen seal strip just slightly longer than the gap between the door and the shower tray or bath — no more than 5mm extra.

This helps create a tight seal.

Example:

2. Measure For Side Seals

Measure the widest point of the gap between the door and the wall or fixed panel.

How To Measure Vertical Seal for Sliding Doors

Sliding doors work differently, so the seal is installed between overlapping panels or between glass and wall.

You’ll need to measure:

1. Glass Thickness

As usual.

 

2.Overlap Gap

Measure the clearance between the sliding door and the fixed panel or wall.

Pro tip Measure Shower Screen Seal

1. If the gap is too small to measure accurately, try slipping a credit card or coin into it, then measure that instead.
2. If your glass door isn’t sitting perfectly straight (maybe the wall’s a bit wonky or the glass was installed at an angle), the gaps at the bottom and sides might not be uniform. To avoid any unwanted drips, Please take the maximum clearance - better safe than wet!

 

Not Sure What to Do?

Here’s the easiest “cheat method” we always recommend to customers:

Take a photo of your shower glass edge with the old seal still on (if possible),
Include the measurements you took.

Then send everything to our friendly support team:

Email: info@showerdoorseal.uk
WhatsApp: +44 0735 2644 608

We’ll help match you with the right seal – no more endless searching or second guessing.

 

 

Got Your Measurements? What’s Next?

Once you’ve got the gap size, glass thickness, and installation style sorted — you’re ready to shop!

We stock a wide range of shower seals made specifically for UK-standard screens, and we’ll ship them straight to your doorstep.

Click here to browse our full range of shower door seals

Need more help?

Read our complete guide on how to choose the right seal – avoid common mistakes and save time

 

 

 

Final Note: Don’t Let a Tiny Seal Ruin Your Shower

A small seal strip might not look like much,

but it can be the difference between a clean bathroom… and a soggy, mouldy mess.

Now you know how to measure, avoid the pitfalls, and pick the right one.

Still unsure? Snap a photo and let us sort it for you.

Ready? Let’s find the perfect shower seal for your screen.

 

 

This article was edited by Laura.

Author: Laura  Liu Laura joined SIMBA in January 2017 and has since become an integral part of the team. As a seasoned content manager and seal expert, she oversees website optimization and specializes in crafting informative and engaging content about sealing solutions. Her deep knowledge of shower seal technology and market trends ensures SIMBA stays ahead in providing value to customers worldwide. Facebook｜ Linkedin