How to Replace Your Shower Screen Bottom Seal: A Simple Guide

Last updated: 2025-12-23

The Ultimate Guide to Replacing Your Shower Screen Seal (UK DIY)

Replacing your shower screen bottom seal is one of the easiest DIY fixes that can save you from water damage and endless cleaning. In this guide, SIMBA will show you how to swap your old, moldy strip for a fresh replacement shower screen seal in 6 simple steps.

How do I replace a shower screen seal? To ensure a watertight fit, remove the old seal by pulling downwards (don't slide), scrub the glass edge to remove limescale, measure the gap accurately, and press the new high-grip seal onto the glass from one corner to the other. Do not use glue.

Tools You’ll Need

Before you start, gather these essential items:

  • Marker pen & Tape measure (Measure twice, cut once!)
  • Garden Secateurs (The secret tool for a clean, professional cut)
  • New SIMBA shower screen seal
  • Cleaning supplies (Vinegar or limescale remover)
Tools for replacing shower seal

Step-by-Step Installation Guide

Step 1: Out With the Old

Open the door fully. Pinch the U-channel and pull straight down. You'll hear a nice little 'pop' as it lets go.

Remove old shower seal
⚠️ A Quick Tip: Don’t try this with the door closed—you won’t have enough vertical space to pull the seal away from the glass.

Pro Tip: Do not slide it off horizontally. This can scratch the glass surface and creates a mess if the seal is old and brittle. Pull straight down.

Do not slide shower seal

Once removed, clear away the grime. It’s the perfect time to choose a replacement shower screen bottom seal to restore that "like-new" look.

Step 2: The Deep Clean

Once the seal is off, you’ll likely see built-up limescale and soap scum. Don't skip the scrub! A clean glass edge ensures your new watertight seal "bites" onto the glass perfectly.

Clean shower glass edge

Dealing with stubborn hard water marks? Watch our quick cleaning tip:

SIMBA Tip: Don't settle for cheap, flimsy strips. Our premium shower screen bottom seals are engineered to stay clear and mold-resistant for much longer.

Step 3: Measure Twice, Cut Once

Most replacement seals (like our 950mm ones) are longer than needed. Trim it to size based on the entire gap that needs sealing, not just the glass door itself.

Check our guide: How to measure glass thickness accurately

Measure shower gap Account for door brackets

Important: Ensure you have the right fit for your glass thickness (usually 4mm, 6mm or 8mm). Browse our full range of thickness-specific seals here.

Step 4: Trimming with Ease

For a professional finish, use garden secateurs rather than a knife. It prevents the PVC from cracking and gives a clean, straight edge. See our full cutting guide here.

Cutting shower seal

Hinge Tip: If the seal hits a metal bracket, just trim off the U-channel in that section and leave the soft fins to maintain the water barrier.

Step 5: Install Your New Seal

Start from the inner side (closest to the hinge/wall). This creates a tight barrier from the inside out for maximum protection.

Install from wall side

⚠️ The Golden Rule: Never slide the seal on. Clip it onto one corner and press upwards bit-by-bit using the palm of your hand. Our high-grip seals are designed to click firmly into place without any messy glue or silicone.

Press on seal step by step

Step 6: Fitting Your Shower Threshold Seal

🎁 A Quick Bonus: When you buy any SIMBA bottom seal, we’ll include a transparent D510 Threshold Seal (worth £14) absolutely free.

Free gift threshold seal

Why use both? The bottom seal is your primary shield, and the threshold is your final line of defence. Together, they create a watertight "dam" that keeps your floor bone-dry.

The #1 Mistake: Leaving Gaps!

One of our customers sent us this photo (below). They left a small gap at the corner, and water escaped instantly. Your threshold must be pushed tightly (FLUSH) against the wall tiles.

Incorrect installation gap

❌ Wrong: Small gap at corner causes leaks

Correct installation flush

✅ Correct: Flush against the wall

Top Tip: If old silicone is blocking the corner, scrape it away with a utility knife so the threshold sits flat against the wall and the tray.

Clean corner silicone

Pro Installation Rules:

  • Peel as you go: Do not remove all the backing tape at once. Press it down inch-by-inch.
  • The 10-Hour Rule: Once fitted, do not use the shower for at least 10 hours to allow the adhesive to cure.
Apply threshold seal

What if the D510 is too wide?

If your shower tray frame is very narrow, choose one of these "pro-fit" alternatives:

The curved rule: If you have a curved screen, you must select the PV29 as it's the only one flexible enough to follow the curve.

🎁 Bonus for PV29 Orders: We’ll include our V312S1235F Universal Seal as a free backup!

No More Leaks!

Seal it right today and say goodbye to soggy bathroom floors. Grab your professional SIMBA seal and enjoy a bone-dry home.

Shop 30,000-Use Tested Seals →

This article was edited by Laura.

Author: Laura Liu

Laura joined SIMBA in 2017. As a seasoned seal expert, she specializes in crafting informative content about sealing solutions and market trends to ensure SIMBA customers get the best value worldwide.

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