What Is Tile Waterproofing (Tanking)?

Tile waterproofing, commonly known as tanking, is the process of applying a waterproof barrier to walls or floors before tiles are installed. Its purpose is to prevent water from penetrating into the underlying structure of the building.

Although ceramic and porcelain tiles are highly resistant to water, a tiled surface is not completely waterproof. Water can pass through grout joints, movement joints and small imperfections over time. Without a suitable waterproofing system behind the tiles, moisture can reach the substrate, potentially causing damage to walls, floors and surrounding building materials.

For this reason, waterproofing has become an essential part of many modern tiled installations, particularly in wet areas such as showers and wet rooms.

Why Is Waterproofing Needed?

Bathrooms, shower enclosures and wet rooms are exposed to regular water and moisture.

Without a waterproof barrier, prolonged exposure can lead to:

• Damp walls.
• Water damage.
• Rot in timber structures.
• Mould growth.
• Damage to plasterboard.
• Failure of adhesives.
• Costly repairs.

Waterproofing helps protect the structure long before these problems develop.

Are Tiles Waterproof?

This is one of the most common misconceptions.

Porcelain and ceramic tiles themselves are highly water resistant, but a tiled installation contains many joints where moisture can pass through.

These include:

• Grout joints.
• Movement joints.
• Pipe penetrations.
• Corners.
• Changes of direction.

The waterproof layer sits beneath the tiles, protecting the building from any moisture that reaches the substrate.

Where Is Tanking Used?

Waterproofing is commonly recommended in areas subject to frequent water exposure, including:

• Shower enclosures.
• Wet rooms.
• Bathroom floors.
• Bathroom walls.
• Steam rooms.
• Commercial changing rooms.
• Spa facilities.

The level of waterproofing required depends on how much water the area is expected to receive.

What Does a Tanking System Include?

A typical waterproofing system may include:

• Waterproof primer.
• Waterproof membrane.
• Joint reinforcement tape.
• Internal corner pieces.
• External corner pieces.
• Pipe collars.
• Drain seals where required.

These components are designed to work together as a complete system.

Does Every Bathroom Need Tanking?

Not necessarily.

Areas exposed to direct and frequent water, such as shower enclosures and wet rooms, are generally considered the highest priority for waterproofing.

Other bathroom areas may require less extensive protection depending on the construction and intended use.

Current installation guidance should always be followed.

Common Misunderstandings

Conclusion

Tile waterproofing, often referred to as tanking, is an important part of modern tile installation. Rather than relying on the tiles themselves to keep water out, a waterproof membrane protects the structure behind the tiled finish from moisture penetration.

When correctly installed as part of a complete waterproofing system, tanking helps prevent water damage, prolongs the life of the installation and contributes to a more reliable and durable bathroom.