Wet rooms have seen a surge in popularity as more homeowners and designers embrace their sleek, contemporary style and space-saving practicality. Unlike traditional bathrooms, a wet room removes the need for a separate shower enclosure, instead incorporating a fully waterproofed open-plan shower area seamlessly into the rest of the bathroom. This not only creates a minimalist aesthetic but also offers ease of access, effortless cleaning, and an efficient use of space.
At the heart of every successful wet room installation lies an effective drainage and waterproofing system. Without these essential components, even the most beautiful tiled wet room could be at risk of water damage, damp, or mould growth. From floor gradients to tanking systems and waste outlets, the drainage and waterproofing elements work together to keep your wet room safe, stylish, and long-lasting.
In this blog post, we’ll take you through the essential facts and considerations around wet room drainage systems, answering common questions and sharing professional insights to help you achieve the best results. Whether you’re a homeowner planning a bathroom renovation or a retailer helping customers choose the right products, this guide is designed to give you confidence in wet room design and installation.
How Do Wetrooms Work?
A successful wetroom installation relies on the precise coordination of three critical elements: floor gradient, efficient drainage, and comprehensive waterproofing. Each plays a vital role in ensuring the space functions correctly, remains safe, and stands the test of time.
- Floor Gradient
The gradient, or slope, of the wetroom floor is designed to direct water efficiently towards the drainage point. This subtle slope is typically built into the floor during preparation and must be consistent across the entire showering area. Without an adequate gradient, water can pool and stagnate, leading to potential issues such as damp patches, mould growth, and even long-term structural damage beneath the tiles.
- Drainage System
A well-planned drainage system is equally important. Wetrooms do not use traditional shower trays, so they rely on either a linear or square drain fitted directly into the floor. These drains must be capable of handling the flow rate of modern showers, especially in family bathrooms or high-use spaces. Choosing high-quality, fast-flow drains and installing them at the lowest point of the floor slope helps keep the wetroom dry and hygienic between uses.
- Waterproofing
Because wetrooms are fully open and exposed to direct water, waterproofing is non-negotiable. Both floors and walls must be completely sealed using a tanking system, such as Quantum’s AquaTank kit and installed over a moisture-resistant substrate such as Baseboard tile backer boards and pre-formed shower trays. This dual-layer system protects the building structure from leaks and moisture ingress, giving homeowners and installers complete peace of mind.
Many wetroom designs also incorporate glass screens to prevent splashing into the dry areas of the bathroom. These screens help contain the shower spray while maintaining a minimalistic, open-plan appearance enhancing both practicality and style.
How Is a Wetroom Waterproofed?
Waterproofing is one of the most essential elements of any wetroom installation, and one that must never be overlooked. Since wetrooms are designed as open-plan spaces where water flows directly onto the floor, it’s critical that the entire area is fully sealed against moisture to avoid long-term damage like mould, rot, or leaks into neighbouring rooms.
Without a robust waterproofing system, even small amounts of water can penetrate the subfloor or wall cavities, leading to expensive structural issues. The risk is especially high in homes with wooden substrates, older properties, or upper-floor bathrooms. A reliable waterproofing solution protects against all of these risks, while providing peace of mind to both installers and homeowners.
At Quantum Group, we recommend starting your wetroom with a solid, moisture-resistant backer board, and that’s exactly what our Baseboard range is designed for. These lightweight yet strong boards provide a dimensionally stable substrate, making them ideal for both floor and wall tiling in wet zones. Manufactured from extruded polystyrene with a reinforced cementitious coating, Baseboards are resistant to water, rot, mould, and thermal changes.
Not only do they eliminate the need for plywood or plasterboard (which can degrade when wet), but they also offer outstanding load-bearing strength and thermal insulation. Baseboard is available in a wide range of thicknesses and sizes, and is easily cut to fit your space, with the range also including pre-formed shower trays with a range of drainage options. It’s the perfect choice for shower enclosures, wetroom floors, and bathroom walls, providing an ideal surface for the next stage of waterproofing.
In cases where the wetroom floor is already stable, level, and load-bearing, StructaMat waterproof movement mattings can serve as an effective alternative to Baseboard backer boards, providing both crack-bridging protection and waterproofing in a single layer beneath the tiles.
Once your surface is stable and secure, the next step is waterproofing. This is where our AquaTank Tanking Kit excels. Designed to treat up to 10m², this complete kit includes everything needed to seal joints, corners, and surfaces before tiling, ensuring a fully watertight barrier across your wetroom.
The kit contains:
- AquaTank Pro-Tile Primer – Enhances adhesion on all backgrounds.
- Neo-Flex Membrane – A ready-to-use flexible waterproof coating.
- SA Tape+ – Butyl-backed sealing tape for joints and pipe penetrations.
- Brushes & full instructions – Everything needed for fast, effective installation.
AquaTank is suitable for both timber and concrete floors, compatible with underfloor heating, and ideal for use beneath porcelain, ceramic, or stone tiles. With fast drying times and easy application, it’s a favourite among professional tilers and is trusted in domestic and commercial projects across the UK and Ireland.
Want to see how they work? Watch our AquaTank installation video and our Baseboard installation video.
By combining Baseboard and AquaTank, you create a powerful, long-lasting waterproofing system that protects the structure of your home and sets the foundation for a flawless tile finish.
Can a Wetroom Be Installed on Wooden and Concrete Floors?
Yes, wetrooms can be successfully installed on both timber and concrete subfloor, but each surface comes with its own set of considerations, and getting the preparation right is essential for long-term performance.
Timber floors, commonly found in upper-storey bathrooms, can absolutely support a wetroom installation when prepared correctly. The first step involves creating a stable, level surface by reinforcing the joists and installing a rigid substrate. This is where Baseboard backer boards excel, as these lightweight yet durable construction boards offer excellent rigidity, dimensional stability, and are moisture- and mould-resistant, making them ideal for creating a secure base over timber.
Concrete floors are naturally more stable, making them an excellent foundation for wetroom installations. However, they often require modification to accommodate drainage components. This might include chasing out (cutting into) the concrete to allow space for a vertical or horizontal drain and the necessary waste pipes.
Once your drainage is in place, it’s essential to apply a layer of Baseboard over the concrete to provide a smooth and absorbent surface for tile adhesive. This step also improves thermal insulation and waterproofing performance. Again, the AquaTank system should be used to create a continuous watertight seal across the entire floor and up the walls, especially in shower zones or high-splash areas.
Can Any Bathroom Be Converted into a Wetroom?
Yes, virtually any bathroom can be transformed into a wetroom, whether it’s a large family bathroom or a compact ensuite. There are no fixed constraints on the size of the shower area, making wetrooms a flexible and space-efficient solution even for small properties or awkwardly shaped layouts. For bathrooms incorporating a toilet and basin alongside the shower area, we recommend a minimum room size of approximately 1.5m x 1m to allow for effective layout and drainage.
When planning a conversion, however, it’s essential to assess the structural condition of the floor, ceiling heights, and pipework access. Proper preparation is critical, especially when retrofitting into older buildings or upstairs bathrooms with timber floors. This includes selecting the right type of tile backer boards, tanking kits and potentially decoupling solutions such as our StructaMat waterproof matting, depending on the substrate.
Above all, proper installation of the wetroom drain is crucial. It must be capable of handling the shower’s water flow while sitting flush with the floor for a seamless finish. Hiring a professional plumber or wetroom specialist is strongly advised, as incorrect falls, drain positioning, or sealing can lead to costly issues such as water leaks, floor rot, or mould growth.
Which Drains Are Available for My Wetroom?
Choosing the right drainage solution is a key component in any successful wetroom installation. The type, position, and capacity of the drain must work harmoniously with your chosen shower tray, waterproofing system, and overall bathroom layout to ensure water is efficiently removed from the space.
In most wetroom designs, drainage is integrated directly into the floor using either a square or linear drain. These can be installed with a vertical or horizontal outlet depending on the available floor void and existing pipework. Horizontal drains are typically the standard choice, while vertical drains are ideal in situations where there are obstacles directly beneath the floor or in older buildings with restricted plumbing routes.
Regular maintenance is essential for any wetroom drainage system. Hair, soap scum, and debris can accumulate over time, so drains should be cleaned frequently to prevent blockages and ensure smooth, uninterrupted water flow.
What Tiles Can I Use in My Wetroom?
One of the key benefits of wetroom design is the ability to create a seamless, fully tiled finish across both floors and walls, but tile selection is crucial. Fortunately, with today’s wide variety of tile styles and formats, there’s something to suit every taste and budget.
Whether you’re aiming for a sleek, spa-like atmosphere with large-format tiles, or a more textured, detailed finish using small mosaics, the design options are nearly endless. However, when selecting tiles for your wetroom floor, slip resistance is non-negotiable. Wet floors can be hazardous, so always opt for tiles with a high slip-resistance rating (typically R11 or higher) to enhance safety.
We recommend avoiding natural stone in wetroom areas, as it tends to be porous and requires regular sealing and maintenance. Instead, opt for porcelain or ceramic tiles, which offer excellent durability, minimal upkeep, and a wide range of designs, from stone and marble effects to wood-look finishes.
Take a look at the Navarro Tiles collection, which includes a carefully curated range of ceramic and porcelain options ideal for wetrooms. With matte finishes, slip-resistant textures, and on-trend colours, Navarro Tiles are a trusted choice for both residential and commercial wetroom projects.
Why Isn’t My Wetroom Draining Properly?
If your wetroom is experiencing poor drainage, the issue is almost always linked to flaws in the original design or installation. It’s why using experienced installers and investing in high-quality drainage components is so critical to long-term performance.
Here are the most common causes of drainage issues in wetrooms:
- Incorrect Floor Gradient: The wetroom floor must slope evenly (typically at a gradient of 1.5–2%) to ensure water flows directly toward the drain. An insufficient or uneven slope can cause puddling and water ingress.
- Inadequate Drainage Capacity: Showers with high water output require fast-flow drains. If the drainage system can’t keep up, water will quickly accumulate on the surface.
- Clogged or Poor-Quality Drains: Drains can become blocked with hair, soap, and debris, particularly if there’s no accessible trap for cleaning. Investing in a removable waste trap can make ongoing maintenance significantly easier.
In large wetrooms or high-use areas, additional drainage may be necessary. This could involve installing a secondary drain or using a pumped waste system to assist with water removal — particularly in rooms where the plumbing is located far from the stack or has minimal fall.
Let’s Build Better Wetrooms Together
At Quantum Group, we understand the challenges that come with wetroom installations. That’s why our Baseboard linear drain trays, high-quality waste pipes, and StructaMat waterproof decoupling membranes are all engineered for reliable performance and easy integration.
Our products are trusted by professionals across the UK and Ireland, and we’re committed to helping our customers create wetrooms that look great, perform flawlessly, and last for years to come.
At Quantum Group, we specialise in professional-grade wetroom waterproofing and drainage systems, including:
- Baseboard pre-formed shower trays and tile backer boards
- AquaTank tanking kits for complete waterproof protection
- StructaMat waterproof matting systems for added flexibility and movement control
All our products are available on a wholesale basis to retailers throughout the UK and Ireland with next-day delivery available. Need help choosing the right components for your next wetroom project? Get in touch with our team today for expert advice, technical support, or product recommendations.