Square DrainTanking is the most important part of any wet room installation and it’s crucial that high quality waterproofing products and systems are used to ensure optimum performance and longevity. At CCL Wetrooms, thanks to over 30 years’experience in wet room design, manufacture and specification, we specialise in the supply and installation of highly effective waterproofing systems. Our knowledge ensures the most effective waterproofing systems are used throughout domestic and commercial wet room projects.

Our expert guide below explores the basics of wet room tanking and the core elements and processes involved to ensure a fantastic finish that will stand the test of time.

Wet Room Tanking Product Materials

The humid conditions of a wet room means that specially designed tanking systems are needed to ensure an effective waterproofing solution. Choosing a specialist provider can give you peace of mind that your chosen tanking products meet the exacting standards of a wet room and are designed with the following crucial elements:

  • Flexibility– Wet room floors are susceptible to a certain amount of movement between the tiles and the substrate, so waterproofing products and systems need to be flexible with effective de-coupling properties to prevent any cracks and avoid tensions.
  • Temperature – Tanking products must be able to cope with the wide variations of temperature that occur in a wet room. This is particularly important if underfloor heating is installed.

Wet Room Tanking Systems

RIW Screedsafe – System for Concrete Floors

RIW Screedsafe
The types of wet room tanking systems required for your wet room will depend on the flooring it is being installed on. For concrete floors, a simple 1mm thick membrane is sufficient for preventing leaks and our RIW Screedsafe is a self-adhesive product that is quick and easy to apply. The membrane itself consists of a 1mm thick rubber modified bitumen waterproof layer, incorporating a woven fabric on one face. This membrane should be installed across the entire wet room floor to ensure optimum waterproofing and has been designed so that you can tile immediately after installation. RIW Screedsafe comes with a lifetime guarantee.

RIW Tilesafe – System for Timber Floors

RIW Tilesafe
For timber floors, a thicker membrane is required to prevent leaks and incorporate decoupling properties. At 2mm thick, our RIW Tilesafe is a highly effective tanking system that features a rubberised bitumen layer incorporated with a woven glass fibre mesh on one side. This too is self-adhesive and can be tiled immediately after installation. We recommend installing the RIW Tilesafe across the entire wet room floor in small wet rooms and at least one metre beyond the shower area in all directions for larger wet rooms. Unlike other waterproofing systems, RIW Tilesafe acts as an acoustic barrier, improving the sound impact insulation properties of a wet room by 11db. Like the RIW Screedsafe, RIW Tilesafe also comes with a lifetime guarantee.

RIW FWM (Flexible Wall Membrane)Wet room Constuction Cross Section

For the walls, an additional tanking system is needed. RIW FWM (Flexible Wall Membrane) is a ready-to-use flexible liquid membrane that should be applied using a brush or short pile roller, to provide a protective, waterproof layer of at least 1mm thick. Reinforcing tape should also be used to reinforce all junctions and flat joints on walls and corners within the shower area.

Wet Room Tanking Process


First and foremost, you must ensure the wet room space is dry, clean and dust free and that you carefully prime the area. Priming is essential for both absorbent and non-absorbent floors, as it seals the foundations of a wet prior to the application of tanking products.

Reinforcing Tape

Next you will need to apply the reinforcing tape to provide added strength for your waterproof membrane in your wet room. This should be applied over all major joints, the edges of the drain, wall corners, soap recesses and any areas where the wall/wall and floorjunctions meet. If there are any electrics or pipes in the way, they too should be carefully sealed with the tape.

Waterproof Membrane Application

The primer must be dry by the time you start applying your tanking products.

Starting in the shower area, apply the RIW Tilesafe membrane to the entire floor area. (For larger wet rooms on timber floors, the membrane should be applied to the floor area finishing a minimum of 1 metre outside the shower area in all directions). Additional RIW Reinforcing tape should be applied to all wall junctions, soap recesses etc within the shower area. RIW FWM (Flexible Wall Membrane) should then be applied to the wetroom walls to ensure a waterproof wall surface prior to tiling. Once the tanking and drainage systems have been installed, the wetroom is ready to be tiled.

Has this wet room tanking guide been helpful? If you have any questions regarding our products, or would like more advice on how to tank a wet room, feel free to get in touch with one of our wet room experts.

For more wetroom technical information check out our technical section.