Creating a reliable waterproofing layer is fundamental to the long-term success of any wet room or bathroom renovation. At The Wet Room Store, we’re proud to introduce our Premium ISO Waterproof Membrane Rolls, engineered to deliver professional-grade performance with ease of application.

In this post, we’ll walk you through the why, when, and how of using waterproof membranes, outline the risks of skipping this step, highlight the benefits, and address a few common questions you might have.

 

Why Use a Waterproof Membrane?

Waterproof membranes are barrier systems designed to prevent water from penetrating through tiles and substrates. Bathrooms and wet rooms are exposed to constant moisture, and even the smallest leaks can cause:

• Structural damage to subfloors and walls
• Mould and mildew growth
• Costly repairs and remediation
• Failure of expensive tile work

Membranes act as a seamless protective layer, ensuring your surfaces remain watertight while preserving the aesthetic integrity of your space.

 

When Should You Use a Membrane?

Waterproof membranes aren’t just for high-end projects—they’re essential protection in any space where water meets structure. Here are the most common (and crucial) scenarios where you should always install one:

Wet Rooms:

Membranes are non-negotiable in wet rooms. The floor and lower wall sections are subject to continuous spray, runoff, and humidity. A membrane creates a sealed tank that prevents water from penetrating the substructure.

Bathrooms with Showers or Baths:

Even if the area is tiled, water can sneak through grout lines and silicone joints. Apply a membrane around and beneath showers, bathtubs, and sinks—especially at junctions and corners where leaks are most likely to develop.

Splash Zones & Tanking Areas:

Any surface exposed to frequent splashing, pooling, or high humidity should be tanked. This includes walls surrounding showers and baths, and the floor area directly outside them.

Before Tiling Onto Vulnerable Substrates:

If you're tiling over plasterboard, plywood, MDF, or cement backer boards, a membrane is critical. These materials are moisture-sensitive and can quickly degrade without proper waterproofing.

How to Use Our ISO Waterproof Membrane Rolls

Here’s a step-by-step guide:

1. Surface Preparation

• Ensure the substrate is clean, dry, and free from dust or debris.
• Fill any cracks or gaps.

2. Priming (Optional but Recommended)

• Apply a suitable primer for better adhesion.

3. Laying the Membrane

• Cut the membrane roll to size using scissors or a knife.
• Apply a thin layer of flexible tile adhesive (cementitious or ready-mixed, depending on the substrate).
• Press the membrane firmly into the adhesive using a roller or smoothing trowel to remove any air bubbles.

4. Sealing the Joints

• Overlap membrane joints by at least 50mm.
• Use ISO Sealing Tape or our Premium Internal/External Corner Pieces at corners and edges.
• Ensure complete coverage and seal continuity.

5. Tiling

• Once the membrane is dry and securely bonded, tiling can begin directly on top using flexible adhesive.

 

Risks of Not Using a Waterproof Membrane:

Many homeowners skip this crucial step, thinking tiles and grout are enough to resist water. They’re not. Risks include:

• Grout Cracks: Allow water ingress, leading to hidden damage.
• Rotting Floorboards: Especially in timber floor constructions.
• Adhesive Failure: Damp can degrade tile adhesive over time.
• Costly Insurance Claims: Many insurers may not cover water damage due to improper waterproofing.

Investing in a proper waterproofing system is essential to prevent these issues and protect your home from expensive repairs.

 

Benefits of Using a Waterproof Membrane:

✔ Premium-Grade: Made from high-quality materials with high water resistance

✔ Flexible & Crack-Bridging: Prevents cracking even on slightly unstable substrates

✔ Quick & Easy to Install: Can be cut and applied with minimal tools

✔ Tiling Ready: No curing or waiting time—start tiling the same day

✔ Compatible with Underfloor Heating: Allows safe and efficient heat transfer

 

Who Should Use It?

• DIY Homeowners: Individuals looking to undertake home improvement projects themselves will find this solution ideal. It offers a professional-grade quality while being designed for easy installation, allowing homeowners to achieve impressive results without requiring expert skills.
• Professional Installers: This solution is also perfect for seasoned professionals in the field who require reliable performance and efficiency. With guaranteed results, it helps installers save time on projects, ensuring they can meet client demands and maintain high standards of quality.

 

Waterproofing is essential; it provides crucial protection for your investment. Our new ISO waterproof membrane rolls, along with accessories like tapes, corners, and sealing kits, offer a comprehensive solution for anyone committed to high-quality wet room and bathroom installations.