You might just need a quick vertical shower door seal strip replacement.
Over time, these slim plastic strips can harden, crack, or simply fall off — leaving water to escape every time you shower.
In this guide, we’ll walk you through when, why and how to replace your vertical seal strip — so your bathroom stays clean and dry.
This article also applies to magnetic shower seals, which are vertical shower seals.
What Is a Vertical Shower Door Seal?
A vertical shower door seal — also known as a side shower door seal — is that plastic strip (usually made from PVC) you’ll find running along the side edge of your shower glass.
To stop water from leaking through the gap between your door and the wall or another panel.
Magnetic seal strips
These come with built-in magnets and are ideal for double glass doors that meet in the middle.
They provide a strong seal and a sleek finish, but usually cost a bit more.
Non-magnetic seal strips
These don’t use magnets. Instead, they rely on soft fins that press against another glass panel or wall to keep water in. They’re great for wider gaps and are more budget-friendly.
Both types of shower seals work well — it just depends on your shower door style and the size of the gap you need to seal.
Common setups include frameless glass doors, sliding doors, and double-opening doors.
When Should You Replace Your Vertical Shower Door Seal Strip?
If your shower door is dripping water from the sides or you're noticing puddles forming after each shower, chances are your vertical seal strip is worn out.
Look for signs like yellowing, cracking, peeling off, or not fitting snugly against the glass.
Most strips need replacing every couple of years, especially in busy bathrooms.
A fresh vertical shower door seal strip replacement not only helps stop leaks but also gives your shower a cleaner, more finished look.
3. How to Replace a Vertical Shower Door Seal Strip (Step-by-Step Guide)
Doing a vertical shower door seal strip replacement might sound tricky, but don’t worry — with the right tools and a little patience, it’s totally doable.
We’ve also included a full installation video at the bottom of this page.
And if you’re still unsure about the seal’s direction, check out our popular guide: Shower Screen Seal: Which Way Round Should It Go?
What You’ll Need:
- A new vertical shower door seal
- Tape measure
- Garden shears
- Clean cloth, water or alcohol spray
Related reads:
Step 1: Open the Glass Door and Remove the Old Seal
If your old seal is yellowing, mouldy, or falling off — good news, it’ll come off easily. Just peel it away gently from top to bottom.
Step 2: Clean the Glass Edge
Use alcohol or clean water and a cloth to wipe down the edge of the glass. This step helps your new seal stick better and last longer.
Step 3: Measure and Cut the New Seal
Use your tape measure to check the glass height, then cut your new seal to the right length.
Need cutting tips? Check out our article: 《 How To Cut Shower Door Seal Easy?》
Step 4: Fit the New Vertical Seal Strip
Here’s where it gets interesting — and we’ll share a pro tip from SIMBA that most people don’t talk about:
a. Use one hand to steady the glass, and hold the new seal in your other hand.
b. Start by hooking one edge of the seal onto the glass. Let the hardness of the glass gently stretch open the U-shaped channel — this makes it easier to slide the seal on smoothly.
This little trick makes a big difference — and you won’t find it on other how-to guides!
At SIMBA, we love sharing these insider tips to make your install smoother.
c. Once that corner is in, slowly work your way down, pressing the seal in bit by bit from top to bottom.
⚠️ Don’t use a hairdryer or heat gun to soften the vertical seal — it might damage the u-shaped rigid channel and lead to poor sealing later.
Our vertical seals are designed with clamping force — we even test this in our quality control process (you can check it out on our testing page).
d. Done? Let’s do a quick check:
How Do You Know the Seal Is Properly Fitted?
Try pulling it gently. If it takes more than 50N of force (that’s roughly the strength of a firm tug) to pull it off, you’ve got a good fit.
If it slides off too easily, the seal might be too loose — it’s best to replace it with one that fits better to avoid water leaks.
Watch the Vertical Shower Door Seal Replacement Video
Now that you’ve read the steps, it’s time to watch it in action. Scroll down to check out our quick installation video and see how simple it can be.
Where to Buy Reliable Vertical Shower Door Seal Strips?
To pick the right vertical shower door seal, you’ll need to know two things:
✔ Your glass thickness
✔ The gap size you’re trying to seal
We’ve covered all the must-know details in our Shower Seal Buying Guide, including expert tips and things most people overlook.
At SIMBA, we offer a wide range of side shower door seal strips in different lengths and fin designs — ideal for frameless, sliding, or double-door shower setups.
Each product includes clear installation direction labels and step-by-step video guides, so you can install it with confidence — no guesswork required.
To save you time, here are some of our most popular side seals we recommend:
8mm Glass H Shape Vertical Seal Gap 4-21mm SIM-0013a
This SIM-0013a seal has a 26mm soft fin, designed to seal gaps between 4mm and 21mm.
The longer fin gives you extra flexibility and helps it stay in contact with uneven floors — ideal for sliding glass doors.
- Catalog Number: SIM-0013a
- Glass: For 8mm Glass
- Seal the gaps: Seals 4–21mm gaps | 26mm soft fin
- Mounting position: Vertical
- Material: PVC
- Color: Clear
- Returnable: 30 Days
- Warranty: 10 months
- Pre-Applied Tape: No tape or glue required
- Installation: Push-in (refer to video for details)
- Can be trimmed to desired length
- View QC Quality Tests
6mm H Shape Vertical Shower Door Seal Gap 2-19mm SIM-0013
This SIM-0013 seal has a 24mm soft fin, designed to seal gaps between 2mm and 19mm.
The longer fin gives you extra flexibility and helps it stay in contact with uneven floors — ideal for sliding glass doors.
- Catalog Number: SIM-0013
- Glass: For 6mm Glass
- Seal the gaps: Seals 2–19mm gaps | 24mm soft fin
- Mounting position: Vertical
- Material: PVC
- Color: Clear
- Returnable: 30 Days
- Warranty: 10 months
- Pre-Applied Tape: No tape or glue required
- Installation: Push-in (refer to video for details)
- Can be trimmed to desired length
- View QC Quality Tests
6mm Glass Vertical Shower Door Bulb Seal Gap 3-7mm | SIM-0014
This SIM-0014 seal comes with an 8mm round bulb fin at the top, making it ideal for sealing vertical gaps between 3mm and 7mm.
It's best used on the side of straight glass doors — not at the bottom. Using it at the base may cause water to collect inside the bubble, leading to mould over time.
- Catalog Number: SIM-0014
- Glass: For 6-8mm Glass
- Seal the gaps: Seals 3–7mm gaps | 8mm bulb fin
- Mounting position: Vertical
- Material: PVC
- Color: Clear
- Returnable: 30 Days
- Warranty: 10 months
- Pre-Applied Tape: No tape or glue required
- Installation: Push-in (refer to video for details)
- Can be trimmed to desired length
- View QC Quality Tests
Final Thoughts: Small Fix, Big Upgrade
Don't wait until your bathroom turns into a puddle. A quick vertical shower door seal strip replacement can save you from bigger problems down the line — like mould, slippery floors, or water damage.
It’s fast, affordable, and makes your shower feel brand new.
Check out our vertical product listings or chat with our support team to find the right fit for your shower.