Jessica Nicholls Author:



When it comes to waterproofing, installing OTL wet room systems is like water off a duck’s back. Are you confident that you’re detailing the correct...

Continue Reading
Blog Post Keeping water under control

When it comes to waterproofing, installing OTL wet room systems is like water off a duck’s back.

Are you confident that you’re detailing the correct waterproofing systems into your projects? Bathroom design is undergoing a revolution and modular wet rooms and pod bathrooms are now an increasingly popular feature of many construction projects. From hotels to luxury apartment blocks, student accommodation to care homes, the emphasis is on slotting in ready-made systems that offer the ultimate tranquil environment once completed. These projects require exacting standards, particularly when it comes to effective waterproofing. For over 15 years, On The Level has provided trade wet room expertise to architects, designers and building contractors, ensuring these modular spaces are totally sealed, effectively and securely.

As showers begin to take centre stage in open plan bathrooms and wet rooms, there are major implications for all aspects of design and construction. Barriers continue to be removed to allow for greater freedom of movement and as the space is opened up and wet areas get larger, it is more important than ever that the waterproofing remains highly effective.

This waterproofing procedure is referred to as tanking. The emphasis is on protecting the immediate showering space and the wider area against leaks and moisture migration.

Tiles, adhesives and grouts alone cannot be relied upon to provide effective waterproofing as they are permeable. They must be supported by a waterproof layer covering the entire splash zone of the room which acts as a barrier to prevent water escaping and causing long term structural damage.

Concerns around effective tanking led to the adoption through building regulation of the British Standard BS5385 Part 4. The standard, introduced in 2004, stipulated that all tiling in wet areas should have a fully sealed, watertight membrane beneath. The membrane must cover the entire floor, together with walls in the wet zone and splash zone. The bottom of all walls also need to be covered, turning up from the floor to a minimum of 100mm.


This tanking system not only acts as a physical barrier, but also flexible one which allows for inevitable structural expansion and contraction. In addition, a compatible sealing tape should be incorporated into the membrane at movement junctions.

There are two main types of tanking systems to choose from. The first is a pre-made sheet membrane which is attached to the wall or floor with adhesive. The second involves a paint-on liquid membrane system, which is either supplied ready-to-use or as a powder and liquid to be mixed together.

The benefits of the latter method include greater flexibility in accommodating changes in temperature and movement. It also has higher weight bearing properties than a sheet membrane, perfect for high traffic areas.

On The Level offers customers a flexible liquid rubber tanking system, available in three different kits, specially developed to eliminate the problem of wet room leaks. It comes in the form of a solvent-free, silicone-compatible sealing compound.

It can be applied to wood, plasterboard, MDF, concrete screed and most commonly used construction boards. It works alongside natural movement within the room and will not become brittle with age. It is also suitable to be used with all forms of underfloor heating, both electric and water.

As well as the primer and sealing tape, the three kits include tanking mats and sleeves to seal around pipes and gullies. The solution provides coverage for approximately 8 square metres. When used in collaboration with On The Level’s comprehensive flooring system, the tanking kits make life far easier for contractors wishing to install modular wet rooms.

Formers can be easily installed wherever required and come with the reassurance of a lifetime guarantee. They are manufactured to exacting standards using sustainably sourced birch plywood, one of the most dimensionally stable ply woods. With laminations bonded together using a phenolic resin, they bring inherent toughness and dependability to wet room construction.

With more than 50 stock size formers available for next working day delivery, On The Level cater for all types of floors and provide a bespoke service for more challenging projects. These custom wet room orders can be delivered in 5 to 7 working days.

On The Level formers are manufactured within their premises in Leighton Buzzard, hand finished, and packaged ready for despatch, as are the tanking systems and channels.

Each product comes with full installation instructions, saving significant time and resources on site, and the 24mm ply can easily be cut and trimmed if necessary for any minor improvements.

It is therefore little wonder that On The Level are the first choice in wet room flooring for some of the UK’s leading construction companies. For the ultimate in flexibility, quality and reliability, our products can be relied upon to deliver and with the addition of the specialist tanking system, offer complete peace of mind. It really is water off a duck’s back!


Got any questions or want to discuss your wet room or shower requirements with us? Contact us on [email protected].