NHBC Guidelines - Waterproofing Bathrooms and Wetrooms

Substrates for tiling bathrooms and Wet rooms

Insights from the New NHBC Technical Guide 2023.

As modern living spaces evolve, the demand for functional and aesthetically pleasing bathroom continues to rise. In particular, Wet rooms, known for their seamless design and luxurious appeal.  They offer a versatile and practical solution for bathrooms of all sizes. Here at WM we have been working to the Scandinavian bathroom waterproofing standards for many years.  As wet rooms grow in popularity, the number of claims of water damage is increasing if the wet rooms haven;t been installed correctly.  It has come a necessity to waterproof our bathrooms and showers. In light of this, the National House Building Council (NHBC) has released a revised technical guide at the end of 2023, highlighting essential practices and standards for wet areas within a bathroom. This guide serves as a crucial resource for builders, architects, and homeowners alike.

Why Waterproofing Matters

Waterproofing a wet room is not merely a recommendation; it is a necessity. Here’s why:

1. Preventing Water Damage: Water can be highly destructive if it seeps into the structure of a building. Over time, this can lead to issues such as mould growth, rotting of structural elements, and deterioration of finishes. Effective waterproofing creates a barrier that prevents water from infiltrating walls and floors, safeguarding the integrity of the building.
2. Maintaining Hygiene: Wet environments can become breeding grounds for mould and mildew if not properly managed. Waterproofing helps maintain a clean and hygienic space by preventing water from pooling and creating damp conditions where mould can thrive.
3. Enhancing Durability: A well-waterproofed wet room is more durable and requires less maintenance. By protecting the underlying structure from water damage, you extend the lifespan of the room and reduce the frequency and cost of repairs.
4. Increasing Property Value: Homes with well-designed and properly waterproofed wet rooms are more attractive to potential buyers. They offer a sense of luxury and reliability, which can significantly increase property value.

Key Takeaways from the NHBC Technical Guide 2023

The NHBC’s 2023 technical guide introduces updated standards and practices for waterproofing wet areas within bathrooms.  Here are some of the key points:

1. Bath and shower areas (not power showers)

All areas around a bath and shower will be subjected to water, therefore it is of upmost importance to ensure the substrate (pre tiling) is fit for purpose.  The substrate must not absorb water and run the risk of becoming damaged.  The NHBC gives clear guidance on suitable boarding and waterproof tanking membranes.

To ensure longevity of the bath or shower area, the surrounding walls should be made watertight.  This is not only to protect the sub structure from damage, it will also increase the life of your tiles and grout.

2. Wet rooms and Power Showers.

A wetroom removes the need for a shower tray and consists of built in slopes to a floor drain.  Typically the shower entrance is flush with the adjacent floor and finished with the same flooring ie tiles.

A power shower incorporates a pump to boost the flow rate (>12 litres/min) of the water it uses.

Both the floor and the walls are subjected to wetting each time the shower is used.  You can not rely on grout and tiles to create a waterproof barrier.  Wetrooms must be tanked. The NHBC guide provides guidance of the zones which should be tanked and the membranes which should be used.  Visit our range of  compliant wet room foundation products

Any plaster based board should not be used in a wetroom regardless of whether a waterproof membrane is installed.

WM have been providing materials and installing waterproofing membranes for over 20 years. Below is the typical zones within a bathroom recommended by WM.  Find out more about our installation service

Implementing Best Practices

Hire Qualified Professionals: Ensure that the installation of your wet room is carried out by qualified and experienced professionals. Proper training and expertise are essential for effective waterproofing.

Choose the Right Materials: Invest in high-quality waterproofing materials that meet the standards outlined in the NHBC guide.  Avoid cutting corners with cheaper, less reliable options.

Follow Manufacturer Instructions: Adhere strictly to the installation instructions provided by manufacturers of waterproofing products. This ensures that you achieve the desired level of protection.

Conclusion

Waterproofing is a critical component of designing and maintaining  bathrooms, showers and wet rooms. The NHBC’s 2023 technical guide provides invaluable insights and standards that help ensure these areas are both functional and durable. By following these guidelines, architects and builders can create beautiful, long-lasting bathrooms and wet rooms that enhance the quality and value of any home. As the industry continues to innovate, staying informed and adhering to the best practices will always be key to success.

Please visit NHBC for a full copy of their guidance.

We’re here to help. If you would like additional information or would like to discuss your wet room project,  get in touch!