12 Item Architect's Guide to Designing a Wet Room

Wet rooms offer sleek design, a space-saving layout, and are easy to clean. This makes wet room bathrooms a top choice for modern households and new builds. When designing a wet room for your clients, you will want to consider aesthetics, functionality and durability, which when combined effectively can produce visually stunning and long-lasting results.

Although your clients will often have great wet room ideas, it can be difficult to balance their vision and budget with practicality. In this article, we will cover 9 areas to consider when developing your wet room design ideas. By considering these right at the beginning of the process, you will be much less likely to run into issues further down the line that throw your plans down the drain.

1. Understand the Client’s Needs

The first thing that you will need to consider when designing a wet room is what vision your client has for the space. This will inform all of your decisions moving forward, so it is vital to get a concrete idea of exactly what your client is after and agree this with them before beginning detailed planning. You will need to balance functional requirements, such as accessibility and durability, with the desire for a visually appealing space. If your client isn’t sure what they would like, then you can provide some inspiration to help get the ball rolling!

2. Select Premium Materials for Durability and Design

Once you have the design and concept nailed, it’s time to select the materials for the project. Consider using high-quality materials, as this will create a luxurious aesthetic and high durability. This can include the typical shower essentials such as high-quality floor tiles, wet room shower trays, and more. But other, less exciting items are perhaps even more important. For example, the type of waterproofing system that you use for the wet room can hugely impact the end result. You can choose between:

1. Sheet Membranes

• Pros: Consistent thickness, easy to inspect visually, strong resistance to movement and cracks.
• Use Case: Ideal for tiled wet rooms, especially with large-format tiles.
• Consideration: Requires precision cutting and overlapping during installation.

2. Liquid Waterproofing Membranes

• Pros: Seamless application, great for irregular shapes or detailing around corners.
• Use Case: Fast application in custom or complex layouts.
• Consideration: Must ensure proper thickness is achieved. Some aren’t compatible with solvent-based adhesives.

3. Foam Backer Boards with Waterproof Coating (e.g., XPS boards)

• Pros: Offers both insulation and waterproofing; lightweight; easy to cut on-site.
• Use Case: Great for custom niches, sloped wet room floors, and building over uneven substrates.
• Consideration: Must use compatible fixings and sealing tape at joints. For a belt and braces approach, consider using a liquid membrane on top of the XPS boards.

Ideally, you will want to balance the quality of the waterproofing system with the overall design that you are going for. Use high-quality parts for the floor finish, drainage systems, wall finishes and adhesives/sealants.

3. Ensure Compliance and Certification for Long-Term Quality

Compliance with UK building regulations and relevant British Standards is a non-negotiable aspect of wet room installation, especially in high-end or commercial projects. From drainage performance (BS EN 1253) to waterproofing requirements (BS 5385-1) and accessibility (Part M), each standard impacts how the space is designed and what components are suitable. Building a wet room area that fits with all these areas is not just a nice-to-have; it is a requirement!  If you’re looking to specify wet rooms for a new build with NHBC, check out their latest guidance.

Ensure that you are up to date on the latest regulations for wet room drains.  There are new BS1253 restrictions on the use of water traps less than 50mm and waterless traps.

Product certification provides added assurance. Choosing BBA-certified waterproofing systems or WRAS-approved fittings ensures the materials used are independently tested and proven to perform. It also simplifies documentation for contractors and helps streamline project timelines. Working with fully certified systems reduces uncertainty, especially when durability and longevity are critical concerns.

4. Optimise Space in Small Wet Room Layouts

The bathroom is often the forgotten room during the building process. Typically, the spare space from the build will be turned into a bathroom, which is then chosen for a wet room conversion later on. This means that space is often not at a premium, and some sacrifices may need to be made. With this in mind, it is important to consider what the key requirements are when installing a wet room.

It must work seamlessly for its users, but functionality doesn’t have to come at the cost of aesthetics. The key is to design with user experience in mind from the outset. This means optimal placement of the wet room shower area, effective zoning, and wet room floor gradients that manage water flow without visible transitions. Proper layout avoids water pooling and keeps the space usable and elegant. Incorporating a well-positioned shower screen can help control water flow without disrupting the open-plan look.

At the same time, specifying products that align with the design vision is essential. Wall-mounted linear drains, for example, offer a sleek aesthetic while enabling single-direction sloping ideal for large format tiles. Recessed shelving, concealed valves, and flush-mounted controls add both convenience and clean visual lines. When performance is embedded within the design language, you can deliver a space that feels both functional and refined.

5. Design with Longevity in Mind

In high-spec projects, longevity isn’t just a bonus, it’s a requirement. Wet rooms are exposed to daily moisture and thermal changes, making material integrity and installation quality critical. Selecting systems with a proven track record in long-term performance, such as decoupling membranes, high-compression strength boards, and corrosion-resistant stainless steel drains, ensures the space will stand the test of time.

Durability also comes down to compatibility. Using products designed to work as a system, such as comprehensive wet room drain kits, reduces the risk of failure at junctions, such as where waterproofing meets efficient water drainage or where tile adhesive interacts with membranes. Investing in quality at the specification stage helps avoid costly repairs later and reinforces your reputation for delivering future-proofed, high-performance spaces.  Once a wet room is installed, you can not easily fix it.  A quality system will last a lifetime.

6. Choose an Effective Water Drainage System

Efficient water drainage is a crucial yet often underestimated component of wet room design. The choice of wet room shower tray plays a key role in directing water efficiently toward the drain while maintaining a seamless finish. It’s not just about removing water efficiently; it also contributes to the aesthetic and influences floor tile layout.

The choice of wet room tray or drain system will influence what drainage format you can use and how water flows through the space. Linear drains, for instance, are perfect for large-format tiles and minimal grout lines, while point drains suit mosaics or spaces with envelope cuts. Choosing the right format allows for precision in both performance and finish.

Beyond style, capacity and certification are essential. A high-end wet room shower area may include a rainfall shower head or multiple outlets, so the chosen drainage solution must be capable of handling the volume of water without pooling. Ensure it complies with BS EN 1253 and consider a 50mm water seal for installations above four floors. Materials matter too! Opt for stainless steel over plastic as it will not crack.

7. Use an Effective Waterproofing System

Waterproofing is arguably the most critical element of any wet room. Failures here can lead to costly damage, reputational risk, and unhappy clients. That’s why the specification should always start with a robust, certified waterproofing system designed for wet zone conditions. Look for membranes that offer crack-bridging capabilities and are compatible with the intended floor and wall finishes, whether it’s natural stone, resin, or porcelain.

Seam detailing is just as important. Corners, junctions, and penetrations (like around drains and pipework) must be treated with precision. Using a complete system, membrane, preformed corners, sealing tape, and compatible adhesives reduces the margin for error and simplifies installation. Choosing eco-friendly, VOC-free systems also ensures your spec meets modern sustainability standards while delivering on long-term protection.

8. Install Proper Ventilation for The Shower Area

Even the best-designed shower room will suffer without proper ventilation. Moisture buildup can lead to mould, material degradation, and uncomfortable conditions. Integrating adequate airflow, whether via mechanical extractors, passive vents, or window placement, is essential to maintaining air quality and preserving finishes. In residential builds, this means specifying fans with suitable extraction rates and timers; in commercial or hotel settings, humidity sensors can add a layer of smart automation.

You should also consider how ventilation affects user comfort and the performance of other elements, such as lighting and heating. Cross-ventilation or zoned air movement can help control condensation, particularly on mirrors and glass panels. Planning for this early in the design stage for your shower enclosure ensures a space that stays crisp, clean, and comfortable, reinforcing the high-end feel your clients expect.

9. Utilise Underfloor Heating for Comfort and Drying Efficiency

Underfloor heating is a must-have in premium wet rooms, not only for user comfort but also for practical drying of surfaces post-use. Low-profile, electric underfloor heating mats can be installed beneath tile or stone finishes without adding significant build-up, helping to maintain level access. Hydronic systems may be preferable in larger developments with existing boiler infrastructure.

It’s also important to coordinate the layout of heating with drainage and waterproofing. Avoid placing heating cables too close to drains or over movement joints to reduce the risk of failure. Pairing underfloor systems with wall-mounted towel warmers or integrated mirror demisters adds functional luxury and speeds up drying, ideal in busy households or hotel settings where quick turnaround is key. Heating enhances not just experience but longevity, by helping surfaces stay dry and reducing mould risk.

Conclusion: Creating the Perfect Wet Room, Designing for the Future

Designing a wet room is a balancing act between creativity and technical precision. For architects, every decision from drain placement to positioning the shower area plays a part in creating a space that looks beautiful, performs flawlessly, and stands the test of time. With increasing client expectations for premium finishes and long-term value, success depends on working with high-quality, fully certified materials and expert support at every stage.

At WM Wetroom Materials, we’re here to help you design with confidence. We partner with top suppliers to ensure the parts that we provide are of the highest quality. Whether you’re working on a single high-end bathroom or an entire multi-residential development, we can help you deliver elegant, future-proofed wet rooms.

If you are looking for high-quality materials to get your next wet room design project going in the right direction, get in touch today.

*Important update to the NHBS Specifications

Backing surfaces for tiling should;

• Be moisture resistant, where frequent wetting occurs 

When Tiling; 

• Proprietary water-resistant grouting should be used in accordance with the manufacturer 

Grouting should be: 

• As specified in the design including mix and colour 
• Cement-based, epoxy resin or a proprietary product 
• ‘Waterproof in and around shower enclosures and where tiling can be saturated’. 

Gypsum plaster should not be used where; 

• ‘Repeated or persistent wetting may occur’