Wet Rooms

“A bathroom in which the shower is open or set behind a single wall, its floor area being flush with the floor of the rest of the room and the water draining away through an outlet set into the floor”.

If the floor of a bathroom is to perform the function of a large shower tray it must be waterproof, capable of directing water to a drainage point and resist movement and settlement without compromising the function of the room as a bathroom.  For a wet room to work efficiently and resist leaks the correct construction methods and tanking products must be combined; one will not work without the other.

Planning a wet room

Consider how the wet room will be used; either solely as a shower room or as a bathroom which will include a wet showering area. If the intention is to create a dedicated shower room, points to consider will include the position of the shower head, drain point location, plumbing, wall and floor coverings and heating.

If the wet area is to be part of a bathroom, the additional functions of the room must also be considered.  A shower creates large quantities of air borne water in the form of spray and this moisture must be contained in order to prevent items such as towels and toilet rolls from becoming damp.  Although a fixed section of glass, often referred to as a walk-in enclosure, will prevent water splashing across the bathroom floor it will not contain air borne spray and if adequate ventilation is not possible, it may be necessary to give consideration to a full shower enclosure.  Condensation will also be an issue if the room is not adequately ventilated.

A shower should not be positioned near to doors or windows and must allow waste water to be easily drained.  The entire floor in a wet room must fall towards the floor drain but if the wet shower area forms only part of a larger room, only the shower area will require a gradient towards the drain. The drainage must be capable of clearing a greater volume of water than the shower is capable of supplying and the pipe work from the drain should be as large and as straight as possible to aid flow and reduce the possibility of blockages.  It may not be possible to route the waste pipe between the floor joists and solid floors may need to be excavated.  Consider taking advice from a qualified professional before starting the project.

Heating and ventilation will also need to be considered carefully. Moisture created should be controlled with adequate heating and ventilation or the room will remain damp, which can cause mould and create unpleasant odours.  Air extraction will remove air borne moisture and combined with under floor heating will dry wet areas and prevent condensation. Under floor heating can be extend into the shower area, but the compatibility of the heating and tanking systems should be checked with the respective manufacturers.

Constructing a wet room

Constructing a wet room is a project which should be considered and planned carefully.  Each element of wet room construction is equally important and ensuring that the room is completely water proof will be of little use if the waste water does not drain away efficiently.  Creating a wet room can be expensive and is not a project where corners can be cut to save money. The bathroom or shower room will need to be stripped back to the bare walls and floor structure.

The floor is the most important aspect of a wet room. It is responsible for carrying water to the drain via a gradient, must be water proof and the construction strong enough to resist movement. The gradient is created with screed or a former on a solid floor and with a former for a suspend floor.

The purpose of the gradient is to channel water to the drain which will be situated at the lowest point of the floor. Suspended floors will require floor boards to be replaced with marine or WBP ply wood (water and boil proof) and a floor former fitted to the showering area. The gradient is only required within the shower and drying area of a bathroom with a shower screen but the tanking should be applied to the floor of the entire room.


Before laying the floor, all the sub-floor drainage and plumbing must be completed.  Once the floor is laid and tiled it is normally very difficult to access the pipe work and it is therefore advisable to use as few joints as possible in the waste and water feed pipes and keep the pipe runs to a minimum. Use the largest waste pipe that the shower waste will allow and ensure that it is capable of draining more water than the shower can supply. A good high flow shower waste should be capable of removing approximately 50 litres of water per minute.

Wet decks

Wet decks or floor formers are commonly manufactured from birch ply wood, abs plastic or a solid surface material such as Hi-Macs.  Wet decks are produced in a range of sizes with the correct fall and drain hole machined into the upper surface and are often supplied in a kit which will include a compatible drain and tanking system.  Most types of wet floor formers are suitable for use on suspended and solid floors. The method of fixing requires the wet former to be fitted to the floor or floor joists before the final screed or over boarding is laid which creates an even surface for tiling.


Tanking is the term applied to the process of making a wet room floor totally waterproof.  This is normally achieved using a specialist propriety product and is undertaken after the completion of all construction, plumbing and drainage but before under-floor heating is installed.

The two most common methods for tanking wet rooms are waterproof matting systems and liquid membrane systems.  Matting systems use a membrane that is applied to the floor using fast set adhesive whilst liquid systems are applied with a brush or roller in conjunction with self-adhesive tape applied to the joints between the floor and walls.  Self-adhesive pads are applied to the areas around the waste outlet and where water supply pipes protrude from the wall.  Tanking is applied to the entire floor and walls within the shower area and can also be applied to a height of between 100 or 200mm up the walls in the remaining areas outside the shower.  If an under-floor heating system is being used in the wet room, it is important to check that it is compatible with the tanking system.

Comprehensive wet room kits are available from specialist manufactures that include a wet room floor former in either standard or a bespoke size, the waste, waste grate, tanking membrane, jointing tape and comprehensive instructions.  Some shower enclosure manufacturers now offer wet room kits and construction materials suitable for both domestic and professional installations.

Wall and floor cladding

Tanked walls and floors can be clad with the same materials commonly used in a bathroom including tiles, stone, glass cladding and solid surface materials.  Vinyl floors, frequently found in level access suited bathrooms for less abled users or medical and care applications are also suitable. Check the compatibility of any adhesives with the tanking supplier before applying wall and floor coverings.

Wet room shower screens

The simple uncluttered appearance of a wet room is complimented by a minimal shower enclosure such as a semi-frameless or frameless glass design.  Shower enclosure brands that supply wet room kits will also offer a choice of suitable wet room screens and shower enclosures.  For the ultimate wet shower room, a frameless glass shower enclosure will enhance the minimal appearance and feeling of space whilst adding a touch of luxury.  A wet room providing only the function of a shower may not require any form of shower screen depending on the size of the area and volume of water supplied by the shower head.

When choosing a shower enclosure, consideration must be given to whether a single glass wet room screen or walk-in panel will adequately contain enough of the moisture created by the shower.  If excess moisture is likely to be a problem, a bespoke shower door fitted to the end of the wet room screen or even a full shower enclosure may be the only way to control the problem.  A full enclosure with an air extract system has the advantage of properly containing spray and air borne moisture.


A properly constructed wet room is a specialist project and should only be undertaken by experienced shower technicians or by competent individuals following thorough research.  Wet room kits offered by specialist wet room companies and shower enclosure manufacturers worth considering and comprehensive instructions including videos, are readily available from manufacturer’s web sites.

Whilst the cost of a wet room kit can be easily ascertained, the costs arising from extensive room remodeling are much more difficult to quantify.  Labour and material costs will be dependent upon the type, construction and age of the property, the size of the room and the intended used of the room as either full bathroom or just a wet shower room.

Based on a room with a total floor area of 6 sq. metres, a complete wet room construction kit excluding the shower screen or enclosure can be purchased for under £1000. Solid floors which require a screeded gradient to be created or larger shower areas may cost substantially more.  A further provision for construction materials other than the wet floor former, tanking and floor drain must also be included in the budget.

Creating a successful wet room is a construction project that should only be under taken after careful consideration and thorough research.  If the wet room is intended to be a DIY project, take advice from the manufacturers of wet room kits and understand the requirements and costs.  Always take up references and inspect previous projects before selecting a specialist company to create a wet room.  If simple, but important guidelines are followed, there is no reason why a modern, stylish and practical wet room cannot be created in most houses.