When it comes to tiling in a bathroom, wet room, or kitchen, getting the waterproofing right isn’t just important — it’s essential. From protecting timber floors and plasterboard walls to ensuring a professional finish around showers and windows, your choice between tanking and waterproofing can make or break the job.
Although often used interchangeably, waterproofing and tanking are two different approaches to creating a water-resistant barrier. Whether you’re renovating a bathroom, building a wet room from scratch, or simply wondering how to tile a wall or tile a floor in a damp area, understanding the difference can help prevent costly damage down the line.
In this guide, we’ll break down:
- What tanking and waterproofing actually mean
- The key differences in purpose, process, and materials
- When to use each method for different tiling applications
- How to ensure compliance with NHBC tanking requirements and best practices
We’ll also cover the most commonly used systems – from liquid waterproofing membranes and paint-on sealants to tanking kits that include everything you need to prep, seal, and protect. So whether you’re searching “tanking kit bathroom”, “waterproofing membrane for shower walls”, or just trying to choose the best waterproofing membrane for tiles, this guide is for you.
What is Waterproofing?
Waterproofing is the process of making a surface resistant to water ingress. In the world of tiling, that usually means applying a barrier – such as a liquid waterproofing membrane, waterproofing paint, or self-adhesive waterproofing tape – to walls, floors, and corners before tiling begins.
Unlike tanking, which aims to completely “tank” or seal a space, waterproofing often focuses on critical zones such as:
- Shower walls and floors
- Bath surrounds
- Wet zones in kitchens and utility rooms
- Tiling a bathroom floor over timber or concrete
- Tiling a kitchen floor prone to spills or splashes
- Window reveals and wall corners where water can collect
These areas are especially vulnerable to leaks, damp, and mould – particularly when tiles and grout alone are wrongly assumed to be waterproof.
Common Waterproofing Methods
There are several ways to create an effective waterproofing layer before tiling:
Liquid Waterproofing Membrane
A paint-on, brushable or rollable liquid that dries to form a flexible waterproof film. Ideal for shower areas, walls, and floors – often included in a shower tanking kit or wet room tanking kit.
Waterproofing Tape
Used to reinforce joints, corners, and gaps – often self-adhesive and paired with a membrane or primer.
Waterproofing Primer
Prepares porous or dusty surfaces for better adhesion and water resistance, especially on plasterboard or cement-based boards.
Waterproofing Sealant or Paint
Specialist paint-on products designed to repel water and seal fine cracks or porous surfaces under tiles.
These systems are typically used under tiles and form a thin but strong barrier that protects everything underneath — from timber joists to tiling backer boards.
Benefits of Waterproofing
Quick and Easy to Apply – especially in small bathrooms or kitchen splashbacks
Flexible and Compatible with most tiling adhesives and substrates
Ideal for Renovations where full tanking isn’t required
Cost-effective for preventing long-term damage
Perfect for Tiling Over – once cured, waterproofing membranes can be tiled directly
What is Tanking?
Tanking is a more comprehensive method of waterproofing — where the goal is to completely seal an area to create a fully waterproof shell. Unlike general waterproofing, tanking is designed to withstand frequent, heavy exposure to water, making it ideal for wet rooms, walk-in showers, shower floors, and commercial tiling projects.
It typically involves using a tanking kit, which contains everything needed to create a watertight membrane across both walls and floors, forming a continuous barrier beneath your tiles.
Where is Tanking Used?
Tanking is commonly used in:
- Wet room installations
- Tanking a bathroom floor before tiling
- Shower tray tanking kits (especially walk-ins)
- Tiling backer boards in high-moisture areas
- Underfloor heating zones where movement and moisture are risks
- Tiling a window sill or recess in a wet zone
- Commercial tiling such as gyms, spas, and hotels
Anywhere that water is likely to pool or be splashed regularly, tanking provides an added layer of defence — particularly important when meeting modern building regulations or NHBC tanking requirements.
Types of Tanking Systems
There are different materials and systems used for tanking, including:
Liquid-Applied Tanking Membranes
These are painted or rolled onto the surface (often in two coats), creating a flexible waterproof layer that adapts to movement and thermal changes. AquaTank Neo-Flex is a perfect example of this type.
Tanking Tape
Used to reinforce corners, joints, and pipe penetrations. Look for self-adhesive options such as AquaTank SA Tape+, designed to simplify the installation process.
Tanking Primers
Improve adhesion and stability on dusty or porous substrates — an essential prep step for successful tanking.
Tanking Slurry or Cementitious Coatings
Used more often in basement tanking and external structures — not typical for tiling but useful in industrial or external waterproofing.
Tanking Membranes (Sheet Form)
Large format sheets (such as bituminous, PVC, or fleece-backed) that are adhered to surfaces. These can be more difficult to fit but are highly effective.
Benefits of Tanking
Fully Waterproof Seal – ideal for walk-in showers and full wet rooms
Crack-Bridging – protects against substrate movement
Meets Modern Building Standards – including BS EN 14891
Compatible with Tiles – can be tiled over with porcelain, ceramic, natural stone and more
Long-Term Moisture Protection – for timber, plasterboard, or screeded floors
Tanking gives you the peace of mind that everything beneath your tiles stays dry and protected, even in the most demanding wet environments.
Key Differences Between Tanking and Waterproofing
While tanking and waterproofing are often used interchangeably, they differ significantly in terms of application, performance, and suitability for different projects. Here’s a breakdown to help you (and your customers) understand when to choose one over the other.
- Purpose & Protection Level
- Tanking is designed to fully block water ingress — creating a completely waterproof barrier. It’s typically used in areas that experience frequent and prolonged exposure to water, such as wet rooms, shower enclosures, and bathroom floors.
- Waterproofing, on the other hand, aims to resist moisture rather than fully contain it. It’s suitable for tiling in bathrooms, kitchens, or splash zones — but not for full wet areas unless combined with tanking materials.
Best for full wet zones: Tanking
Best for splash zones: Waterproofing
- Application Process
- Tanking systems (like the AquaTank Kit) include a liquid waterproofing membrane, primer, and tape — applied in a specific order to create a sealed surface that’s ready to tile in as little as 2 hours.
- Waterproofing methods may include paint-on waterproofing membranes, sealants, or adhesive tapes used independently or in combination with other materials. These are typically faster to apply but less robust for high-risk areas.
Tanking = More layers, more complete protection
Waterproofing = Faster, simpler for general use
- Materials Used
- Tanking materials:
- Liquid waterproofing membranes
- Self-adhesive waterproofing tapes
- Primers
- Sheet membranes (for some commercial systems)
- Waterproofing materials:
- Waterproofing sealants and paint
- Sheet rolls for damp-proofing
- Self-adhesive waterproofing membranes for kitchens/bath splashbacks
Tanking materials form continuous waterproofing layers, while waterproofing materials tend to repel moisture rather than seal against it.
- Cost & Time Considerations
- Tanking kits cost slightly more due to the multi-step application and higher spec materials — but they offer guaranteed long-term protection and often meet regulatory standards (like NHBC tanking requirements).
- Waterproofing products are generally cheaper and quicker to apply but may require recoating or repairs sooner in high-moisture areas.
Think of tanking as an investment in long-term durability, especially where tiles are installed over timber floors or plasterboard walls.
- Maintenance & Durability
- Tanked surfaces, when properly installed, offer long-lasting protection with minimal maintenance. They resist cracking, movement, and water vapour.
- Waterproofed surfaces may need more frequent checks, especially if using waterproofing sealants, which can degrade over time or peel in poor conditions.
Tanking = Set it and forget it
Waterproofing = Great for light-use areas, but less robust
In Summary – Which Should You Use?
| Scenario | Recommended |
| Tiling a bathroom floor | Tanking kit |
| Tiling a shower wall | Tanking membrane + tape |
| Tiling kitchen floor | Waterproofing may suffice (if low risk) |
| Waterproofing under tiles in a wetroom | Tanking system |
| Waterproofing behind tiles on plasterboard | Tanking or waterproof membrane |
| Sealing around a window sill in a bathroom | Waterproofing tape or liquid tanking |
| General tiling for kitchen splashbacks | Waterproofing sealant or primer |
If in doubt — tanking offers more protection, and it’s always easier to prevent leaks than to fix them later.
Still Not Sure?
Ask yourself:
- Will water pool or run on this surface every day? → Go with tanking
- Is it a splash zone or occasional damp area? → Waterproofing may be enough
- Do I need to meet NHBC or BS EN 14891 standards? → Use a tanking system
- Is it a commercial bathroom or high-use family shower? → Always tank it
Waterproofing vs. Tanking – Which Is Right for Your Project?
While both tanking and waterproofing aim to protect tiled surfaces from water damage, they serve different purposes and should be applied accordingly.
- Tanking is the gold standard for wet zones like bathrooms, wet rooms, and showers, offering a full barrier under tiles that prevents water from ever reaching the substrate.
- Waterproofing is ideal for splash zones, kitchens, utility rooms, or low-risk areas where water exposure is minimal.
If you’re working on a wet room installation, tiling a bathroom floor, or installing tiles around a shower tray, tanking with a complete waterproofing membrane system is essential — especially when meeting NHBC guidance or BS EN 14891 standards.
Choosing the right method doesn’t just protect your tile job — it protects the entire structure behind it.
Ready to waterproof with confidence?
Explore the AquaTank Waterproofing Range – from shower tanking kits to membranes, primers, and sealing tapes, all designed to work together, dry fast, and last for years.
Frequently Asked Questions (FAQs)
What is a waterproofing membrane?
A waterproofing membrane is a layer of material (liquid or sheet) applied to surfaces like walls or floors to prevent water from penetrating through. It’s essential for protecting substrates under tiles, especially in bathrooms and wet rooms.
Where should I use waterproofing membrane under tile?
Use a waterproofing membrane beneath tiles in high-moisture areas such as shower enclosures, bath perimeters, wet room floors, and around window sills. This helps protect the surface from water ingress and tile failure.
What’s the best waterproofing membrane for a bathroom floor?
For tiled bathroom floors, a liquid waterproofing membrane like AquaTank Neo-Flex offers flexible, crack-bridging protection and is ideal for use under tiles. It’s fast-drying and easy to apply.
Do I need waterproofing for tiling in the bathroom?
Yes — especially in showers, wet rooms, or any area exposed to frequent water. Without a waterproofing layer, water can seep through grout or cracks and cause structural damage.
What is a tanking kit?
A tanking kit is a complete waterproofing system that includes a membrane, primer, and tape or sealant to create a watertight surface before tiling. It’s commonly used for bathrooms, showers, and wet rooms.
How is tanking different from waterproofing?
Tanking involves fully sealing a surface using a waterproof membrane — essentially creating a ‘tank’ that holds back water. Waterproofing is a broader term and can include lighter protection using sealants, paint, or partial membranes.
How long does tanking last?
When installed properly using high-quality products like the AquaTank Waterproofing Kit, tanking can last many years — often the life of the bathroom or wet room. Maintenance and correct application are key.
What is the best tanking kit for a wet room?
It should include a flexible membrane, self-adhesive waterproofing tape, and a primer — all ready to tile in just a few hours.
Do I need to tank behind tiles in a shower?
Yes. Tile and grout are not fully waterproof. Tanking behind shower tiles ensures water doesn’t reach the substrate, helping prevent mould, damp, and long-term damage.
How do I apply a waterproofing membrane for tiles?
Clean and prime the surface, apply self-adhesive waterproofing tape to joints and corners, then apply a liquid membrane in two coats. Allow to dry before tiling.
Can I use waterproofing membrane on walls?
Absolutely. Wall waterproofing membranes are critical in shower enclosures, around windows, or anywhere exposed to regular moisture.
Can I waterproof using paint?
Paint-on waterproofing membrane products can work well when applied correctly. Look for flexible, fast-drying options suitable for use under tile.
Do I need a waterproofing primer before applying membrane?
Yes — a bonding primer like AquaTank Pro-Tile Primer improves adhesion and ensures the membrane performs effectively, even on dusty or absorbent substrates like plasterboard or cement board.
Can I tile directly onto waterproofing membrane?
Yes — once fully dry, membranes like Neo-Flex can be tiled over using flexible tile adhesive, suitable for tiling a kitchen floor, bathroom wall, or wet room floor.
Is waterproofing necessary when tiling for a kitchen?
While not essential for every area, waterproofing under tiles in kitchen splashbacks, behind sinks, or around windows can prevent moisture damage from spills and condensation.
Should I waterproof window sills before tiling?
Yes — tiling a window sill in a bathroom or kitchen should always be preceded by waterproofing tape or membrane to protect against leaks and condensation build-up.
What’s the difference between a wet room and a walk-in shower?
A wet room is a fully tanked, open-plan bathroom with level access and drainage. A walk-in shower typically has a tray and enclosure. Wet rooms require full surface tanking, while walk-in showers may only need partial waterproofing.
How do I create a wet room that’s waterproof?
Use a full wet room tanking kit, including membrane, primer, and waterproofing tape. Ensure the floor is correctly sloped to the drain and all walls are tanked up to at least 1.2m, or higher in the shower zone.
Can I use waterproofing membrane over backer board?
Yes. Tiling backer board should always be waterproofed before tiling — especially in wet zones. Membranes like Neo-Flex are ideal for use over cement or foam boards.
What’s the best way to waterproof a floor before tiling?
Apply a bonding primer, seal joints with waterproofing tape, and roll or brush on two coats of liquid waterproofing membrane. Once dry, it’s ready to tile.
Is tanking required for underfloor heating systems?
Yes — areas with underfloor heating are prone to thermal movement. Use a flexible, crack-bridging waterproofing membrane like Neo-Flex before laying tiles.
Sourcing & Support
Where can I buy AquaTank Waterproofing products?
AquaTank is available exclusively through approved retailers across the UK and Ireland. We do not sell directly to trade. To find your local stockist, contact us here.
How do I choose the right waterproofing system?
If you’re unsure whether you need paint-on waterproofing, a full tanking kit, or self-adhesive membrane, speak to your retailer or contact the AquaTank team for guidance.