Wet Room Installation

The basis of any wet room, is creating a fully waterproof environment (sometimes called 'tanking'), with a level access tiled shower tray and a floor drain. When coupled with an underfloor heating system, the room will take on the appearance and feel of a luxurious spa

Creating a wet room in your house requires some planning, but is not out of reach for a competent DIY enthusiast. The Tile Source provides a full range of solutions for the creation of your dream wet room i.e. waterproofing different types of wall and floor substrates or sensitive / vulnerable areas etc.

To plan your wet room there are a number of simple steps you need to follow:

Ensure the surfaces are stable
Locate water and power points and establish where you wish to position your Marmox wet room shower tray and floor drain (view The Tile Source available Showerlay trays sizes), checking that that the drain outlet has a sufficient fall and that there are no obstructions like metal beams in the way (Note. screeded floors will require some of the screed to be removed if you wish the finished shower to be flush with the floor)
Are you installing an underfloor heating system and if so which is the most appropriate for you wet room project? (see the Underfloor Heating advice page for a detailed description of each of the underfloor heating systems available, their benefits and suitability to different environments)
Find out the correct waterproofing technique for your wet room walls and floors (see Waterproofing Wet Room Walls and Waterproofing Wet Room Floors below)
Choose tiles for your wet room project, being careful to review their suitability i.e. porosity, wear rating, slip resistance, weight, size etc. (Check the Types of Tile advice page to find out the different properties of different types of tile and their suitability to different situations and applications)

Note. The installation process can take several days to complete so you must account for the room being out of order for this time

Planning a Wet Room Project Waterproofing Walls Waterproofing Floors

Grout Recommendations Shower Trays Drainage Underfloor Heating

Waterproofing Wet Room WALLS

How you waterproof the wall of your wet room will depend completely on the wall construction type

The Tile Source supply a variety of different task specific waterproofing products, suitable for a wide range of different substrates - and all at the very best possible prices!

Please find below a table listing the most common types of wall substrate and our recommended waterproofing solutions for each type

stud work Partition

(metal or timber frames)
Secure 10mm or 12.5mm thick tile backer boards to the stud work partition using the dry lining technique (Note. Maximum weight of tile and adhesive on tile backer board = 62Kg per m²)

Instructions

Fix tile backer boards using fifteen 1.5" SUPA PRO screws and SUPA PRO, tile backer board washers
Apply a high quality silicone sealant (such as Dow Corning 785) to the edges of the board before butting up the next board to be fitted
Ensure the edges of the boards are fully supported by the stud work partition
Seal all board joints with BAL Polyester Tape and cover with a skim coat of cement based tile adhesive (i.e. ProFix Flexible Fast Set Adhesive)
Fit angled tile backer boards closely around any extruding pipe work or shower fittings and fill any small gaps with silicone sealant, if the gaps are larger than 1.5mm however, use BAL Polyester Tape and BAL WP1 tanking coating

Plasterboard/Plywood

If the plasterboard / plywood is fixed to stud work partition walls we recommend that it is removed and replaced with tile backer board using the dry lining technique (Note. Maximum weight of tile and adhesive on tile backer board = 62Kg per m²)
See stud work partition section for dry lining fixing instructions

Alternatively Either

Use a waterproof tanking system such as BAL WP1 or Ardex WPC (note. the tile and adhesive combined weight must not exceed 19Kg per m²)

Instructions

Prime all surfaces with BAL Prime APD and allow to dry (15-30 mins)
Using a suitable brush or steel float, apply BAL WP1 waterproof coating at:
- Internal and external corners of walls/partitions
- Wall junctions with bases / upstands / columns
- At pipe penetration points / drainage channels / outlets
- Junctions of different bases / background materials
- Cracks and joints in background/base
Reinforce with BAL Polyester Tape
Apply second coat of BAL WP1 waterproof coating over the BAL Polyester Tape
Using a brush or steel float, apply BAL WP1 waterproof coating to primed walls at a max. 2mm thickness
Allow membrane to dry for min. 24 hours before tiling
When dry, the background is suitable for both ready-mixed or cementitious powder adhesives (wall adhesives only) - NO additional priming required

Note. BAL WP1 waterproof coating does NOT provide a wearing surface (i.e. cannot act as the finished surface - it must be tiled over)

OR

Fix tile backer boards through the substrate to the stud work beneath using the dry lining technique (Note. Maximum weight of tile and adhesive on tile backer board = 62Kg per m²)
See stud work partition section for dry lining fixing instructions

OR

Fix Schluter KERDI matting over the top of the plasterboard / plywood substrate.(Note. the tile and adhesive combined weight must not exceed 18Kg per m²)
See the Schluter KERDI Matting Product Information Sheet for full fixing instructions

Note. The back and edges of a plywood board must be fully sealed, and the board allowed to acclimatise to its environment for 24 hours, prior to waterproofing

Plaster, Brick & Blockwork

Secure 10mm or 12.5mm thick tile backer boards to the substrate using one of the two methods below:
(Note. Maximum weight of tile and adhesive on tile backer board = 62Kg per m²)

EITHER

Fix the boards using a flexible cement based tile adhesive (i.e. ProFix Flexible Fast Set Adhesive). After the boards have been fixed in position, drill nine 10mm holes through the board and hammer a 60mm spanker into each, for additional security

OR

Fix the boards through the substrate to the studwork beneath using the dry lining technique
See Studwork partition section for dry lining fixing instructions

Render

There are three different ways of appropriately waterproofing a rendered substrate for a wet room installation.

Note. ALWAYS ensure the rendered surface is sound, clean and more than 2 weeks old, prior to applying your waterproofing techniques

EITHER

Fix Schluter KERDI Matting to the rendered substrate
(note. the tile and adhesive combined weight must not exceed 38Kg per m²)

See the Schluter KERDI Matting Product Information Sheet for full fixing instructions

OR

Use a waterproof tanking system such as BAL WP1 waterproof coating or Ardex WPC
(note. the tile and adhesive combined weight must not exceed 39Kg per m²)

See Plasterboard / Plywood section for waterproof tanking instructions

OR

Fix tile backer boards through the substrate to the studwork beneath using the dry lining technique
(Note. Maximum weight of tile and adhesive on tile backer board = 62Kg per m²)

See Studwork partition section for dry lining fixing instructions

Existing Tiles

Ensure the surface is free from grease, dust, dirt etc and that the weight of the new tiles, waterproofing, the old tiles and all the adhesive will not exceed the weight permitted for the underlying surface (plaster 20kg, plasterboard 32kg, render 40kg and tile backer board up to 62kg)

It is also essential to ensure all existing tiles are properly secure/bonded - replace any tiles that are not securely fixed and ensure the surface is completely level. If a large proportion of the tiles are broken or not effectively bonded, you might consider stripping the tiles back to the substrate and then waterproofing the background substrate (the method of waterproofing the background substrate is dependent on its type i.e. brick / blockwork, studwork partions - see other sections for relevant waterproofing technique)

If the tiles are sufficiently level and bonded; fix Schluter KERDI Matting to the existing tiled surface
(note. the tile and adhesive combined weight must not exceed 38Kg per m²)

See the Schluter KERDI Matting Product Information Sheet for full fixing instructions

Planning a Wet Room Project Waterproofing Walls Waterproofing Floors

Grout Recommendations Shower Trays Drainage Underfloor Heating

Waterproofing Wet Room FLOORS

Waterproof your wet room floor with complete confidence. How you waterproof the floor of your wet room will depend on the floor construction and what type of underfloor heating system you will use. You will also need to consider the finished floor level and how the shower tray, drains and floor relate to each other.

Every project is unique, so everyone has different priorities resulting in different solutions. See The Tile Source choice of preferred waterproofing solutions; Genesis G-Mat, tile backer board and Schluter DITRA Matting, each with distinguishing characteristics and technology, appropriate for a variety of different applications (all waterproofing solutions and fixing instructions detailed below) - find the right system for your project. ALL the products listed are available from stock and at the best possible prices!

Note. You should have already checked that your shower drain and shower tray will fit and work (step 2 in planning your wet room) and before choosing a suitable waterproofing solution, you will also need to consider your finished floor height.

Getting your Levels Right

The finished floor height will determined by:

Type of tile (10-20mm)
Type of adhesive (3-5mm)
The possible inclusion and type of underfloor heating system (cable = 5mm, matting = 4mm)
The possible inclusion and size of tile backer board for heat insulation & waterproofing purposes, (available in 6mm, 10mm, 12.5mm or 20mm depths)

Note. In new-builds, the finished floor height can be considered in advance and incorporated into the design, so that the finished floor is flush with the external flooring. In renovation projects, however, the extent to which the floor level is altered is highly significant i.e. a large step up into the room may not be suitable. Consider, does the door swing inwards?

Waterproofing Solutions and Fixing Instructions

It is likely the floor of the proposed wet room will be either screeded (concrete) or timber based; both will need waterproofing. Ensure your timber based flooring is fixed and rigid, screw down any loose floorboards, taking into consideration water pipes below.

Genesis G-Mat

G-Mat is a thin waterproofing membrane and decoupling system (i.e. movement in the floor will not be transferred through the tiles; ideal for use on timber substrates) - with an installation height of only 3mm. Made from high-density polyethylene, it is completely impervious to water, and resistant to rotting and reactive substances (i.e. solvents, alkalis and oils).

Uses

Sealing in very damp/wet areas - prevents the entry of water into the substrate (ideal for use in wet rooms, bathrooms, changing rooms and swimming pool surrounds)
Sealing in outdoor areas - water/frost resistant and able to withstand temperature fluctuations without affecting the tiled covering (ideal for use on balconies and patios)
Laying tiles on timber substrates - decouples the covering from the substrate, allowing the timber substrate to expand and contract in reaction to temperature or humidity changes without affecting the tiled covering
Laying tiles over underfloor heating systems - decouples the covering from the substrate, allowing heated screeds to expand and contract without affecting the tiled covering
Bridging cracks in the substrate - allows tiles to be laid on damaged, 'cracked' substrates and old floor coverings (ideal for use in renovations and laying tile on tile)
Laying tiles on fresh substrates - allows reverse vapour pressure equalisation, making it possible to lay tiles on substrates which are not yet fully dry (particularly useful for laying tiles on anhydrite floating screed, without special treatment and adhesive)

NOT SUITABLE FOR USE ON WALLS

Fixing Instructions:

Ensure surfaces are flat, clean, dry, sound and free from contamination
Cut the G-Mat rolls to the required lengths (G-Mat comes as a 1m width roll)
Apply a flexible thin bed adhesive to the substrate (look at the adhesive advice page to find the recommended adhesive for your substrate)
Comb the adhesive bed to the required thickness (look at the adhesive advice page to find the recommended trowel type for your substrate) - ensure all the ribs run in the same direction
Lay the G-Mat over the adhesive, with the woven carrier fleece facing downwards, and gentle mallet/hammer flat (the mats must be laid before the adhesive forms a skin - if a skin does form, simply remove the adhesive and apply a fresh layer)
Note. Access crawl boards should be used to prevent damage to the mats during installation
Seal all joints (mat to wall, mat to mat, all corners and around piping etc.) using waterproofing tape
Once the mat adhesive has hardened (follow the manufacturers recommended drying times, found on the product packaging) tiles can then be laid directly onto the mat using a thin bed tile adhesive

Note. G-Mats must NOT bridge movement joints in the sub floor. The integrity of the joints must be maintained through the mat to the tile bed.

Tile Backer Board

Tile backer boards are waterproof, heat and sound insulation boards. They are made from extruded polystyrene, covered with a close woven fibreglass mesh embedded in a cement polymer mortar. The boards are lightweight and easy to cut to size / shape, allowing for a quick and easy installation process.

Uses

Sealing internal areas subject to very wet/damp conditions - fully waterproof to prevent water passing through the boards and into the substrate (ideal for use in wet rooms, bath rooms, kitchens and showers)
Heat insulator - decreases the level of heat escaping through the boards into the substrate, allowing a greater proportion of heat upwards into the room (a cost effective solution ideal for use with underfloor heating systems)
Load bearing - allows heavier wall tiles to be fixed (holds a tile weight of 62 kg/m², double that of plasterboard and many other tile backer boards)
Sound insulator - reduces the transfer of sound waves through the boards (ideal for use in music / rehearsal rooms, recording studios)
Bridging cracks in the substrate - allows tiles to be laid on damaged, uneven, 'cracked' substrates and old wall or floor coverings (ideal for use in renovations and laying tile on tile)

NOT SUITABLE FOR USE EXTERNALLY OR AS A DECOUPLING MEMBRANE. TILES NO SMALLER THAN 50 x 50MM SHOULD BE USED ON MARMOX FLOORING APPLICATIONS

Fixing Instructions:

Ensure all existing finishes (i.e. varnish, wax, paint) are removed and that the substrate is level, clean, sound and dry/fully cured (follow the manufacturers recommended drying/cure times, located on the product packaging)
Apply a tile adhesive to the substrate (look at the adhesive advice page to find the recommended adhesive for your substrate). Note. You must NOT use a solvent based adhesive
Comb the adhesive bed to the required thickness - ensure all the ribs run in the same direction
Note. Any depressions in the substrate should be taken up with the thickness of the adhesive
Starting in one corner of the room, lay the boards in a staggered (brick bond) pattern
Cut the boards, where applicable, to fit the room dimensions and butt the boards against each other
Note. Leave a 5mm gap between the boards and the wall
When using Marmox boards over a timber substrate it is advisable fix the boards using fifteen SUPA PRO screws and SUPA PRO tile backer board washers (The screw lengths should be a maximum of the Marmox board thickness and the thickness of the timber floor)
Seal the 5mm gap between the boards and wall using waterproofing tape
Allow the tile adhesive to dry (follow the manufacturers recommended drying times, located on the product packaging)
Seal all board joints with waterproofing tape or fibreglass reinforcing tape scrim

Note. Marmox tile backer boards must NOT bridge movement joints in the sub floor. The integrity of the joints must be maintained through the board to the tile bed.

Schluter DITRA Matting

Schluter DITRA matting is used as a waterproofing membrane and uncoupling system. It is therefore ideal for timber substrates, as it prevents the movement in the timber floor from being transferred through to the tiled surface.

Uses

Schluter DITRA matting is a thin waterproofing membrane and decoupling system (i.e. movement in the floor will not be transferred through the tiles; ideal for use on timber substrates) - with an installation height of only 4mm. Made from high-density polyethylene, it is completely impervious to water, and resistant to rotting and reactive substances (i.e. solvents, alkalis and oils).

Fixing Instructions:

Ensure the substrate is free of bond inhibiting components, is load bearing, and even (must be levelled prior to the application of Schluter DITRA)
Cut the Schluter DITRA to size
Apply a bonding adhesive to the substrate using a 3x3mm or 4x4mm notched trowel (the type of bonding adhesive used depends on the type of substrate - check out The Tile Source Adhesive Advice Page more information regarding the different types of adhesive available and their compatibility with different substrates)
Embed the anchoring fleece (on the underside of Schluter DITRA in the adhesive) into the adhesive, stretching the DITRA as it is laid
Work the DITRA into the adhesive using a float or screed trowel to ensure it is fully bonded to the adhesive
Ensure the mats are straight and butted to one another (NOT overlapping and NO gaps)
Seal; the joins in the matting, the joint with the Marmox Showerlay tray and the joint between the floor and wall with Schluter KERDI KEBA waterproofing tape fixed with KERDI COLL adhesive. For quick and efficient corner seals use KERDI KERECK preformed external and internal angles with KERDI COLL adhesive
Remove any moisture that may have gathered in the indentations of the studs before applying the thin-bed tile adhesive
Tiles can be set immediately after the Schluter DITRA matting is installed

Note. All new screeds need to be dry and fully cured before commencing tiling (typically 4 weeks)

Planning a Wet Room Project Waterproofing Walls Waterproofing Floors

Grout Recommendations Shower Trays Drainage Underfloor Heating

Grout Recommendations

In a wet room installation the use of polymer modified grouts are advised. The Tile Source offers a wide selection of polymer modified grouts from leading brands BAL, Ardex and Bostik. Polymer modified grouts are more water resistant and resilient to the force of water that some power showers can generate. If your wet room receives a lot of continued use or if your water supply is slightly acidic you may wish to consider epoxy grouts.

Check out the Tile Source Grout Advice Page for more information on the different types of grout available and their different uses.

Planning a Wet Room Project Waterproofing Walls Waterproofing Floors

Grout Recommendations Shower Trays Drainage Underfloor Heating

Shower Trays

A wet room shower tray is a waterproof and fully load-bearing, floor level preformed tray, which is pre-laid to falls to ensure efficient drainage. A shower tray can be laid directly onto existing wooden or concrete floors, however if the desired shower area is to be level access, the shower tray can either be cut into the floor and reinforced beneath, or, the surrounding area raised using Tile Backer Boards. Alternatively the shower tray base could be higher than the rest of the floor and a raised step formed around the tray.

The Tile Source wet room tray range has a selection of different low cost Marmox Showerlay shower trays in a variety of shapes and sizes, with centre and offset drain outlets, to accommodate all shower area layouts and subfloor construction types.

Marmox Showerlays are made with a fully waterproof closed cell polystyrene core, covered (front and back) with a close woven fibreglass mesh embedded in a cement polymer mortar for added strength. See a list of their key features and applications below.

Key Features

Floor level - easy access
Pre-formed slope to drain
Cost effective
Available with offset or central drainage
Available in a wide range of different shapes and sizes
Easy to cut to size / shape - can cut to fit on site
Lightweight and easy to handle
Ready to receive a tile/mosaic finish
Load bearing - sufficiently robust to be tiled with mosaics as small as 50 x 50mm
Suitable for internal use ONLY
Suitable for use on timber or concrete floors

Note. A Marmox Showerlay, walk-in shower tray, is ideally suited for use with a Marmox Dallmer drain and Marmox tile backer boards - a complete combination, for creating your dream wet room finish

Fixing instructions

Click here to download detailed instructions for fixing wet room shower trays to both timber and concrete substrates

Planning a Wet Room Project Waterproofing Walls Waterproofing Floors

Grout Recommendations Shower Trays Drainage Underfloor Heating

Drainage

It is necessary to consider the floor depth of your room in order to determine what type of floor drain is suitable for your project. The Tile Source offers two types of drain design, from leading experts Dallmer; a horizontal outlet design and a vertical outlet design. The horizontal outlet has a slim profile, at just 83mm depth below the shower tray. It maximises space usage to accommodate buildings with a smaller floor depth level - ideal for renovation projects.

The Dallmer Marmox Shower Drain has been specially developed to perfectly fit to the Marmox Showerlay Tray (also supplied by The Tile Source) for a complete wet room design.

The Dallmer Drain Includes

DN50 connector with adaptor (50mm external dimension/43mm internal dimension) for 2" British Standard pipe. Solvent weld fitting. (Note. Not suitable for fixing with non British Standard/EU piping or polypropylene drainage)
Extension frames for thicker tiles
137mm stainless steel drain plate
Removable trap

The Dallmer Drain has an exceptional discharge rate of 0.5 litres per second as per EU EN274 test with a 3 degree fall on a 2m outlet pipe

Planning a Wet Room Project Waterproofing Walls Waterproofing Floors

Grout Recommendations Shower Trays Drainage Underfloor Heating

Underfloor heating

A wet room would not be complete without an underfloor heating system. The luxury of walking on warm tiles has to be felt to be believed! Plus, it has the added advantage in a wet room, of helping to keep the floor dry.

Magnum Electric Underfloor Heating have three solutions available:

Magnum enerCable, this can only be installed in a new screed and is not suitable for timber floors or old screeds. It will not raise the floor height and is particularly cost effective. It will require an electrician and the placing of a thermostat on the wall and a sensor in the screed. If using enerCable you must use the Schluter DITRA matting and KERDI waterproofing system.
Magnum enerMat, this would be installed on top of the waterproofing and would raise the floor by 5mm. It will require an electrician and the placing of a thermostat on the wall and a sensor in the floor.
Magnum enerFoil, this very safe low voltage system would be installed on top of the floor waterproofing and would raise the floor by less than 1mm. No sensor or thermostat would be required, however it is run off a transformer that would need to be nearby (for example in a wardrobe) and it would require a three pin socket

Check out our Underfloor Heating Advice Page for a comprehensive list of ALL the different types of underfloor heating systems available from leading brands Devi, Magnum and Schluter. Find out the key features and properties of the different systems and their suitability to a range of different substrates, environments and applications. Plus, check out our underfloor heating insulation recommendations and underfloor heating accessories.

If you have any further queries regarding wet room installations, please give us a call on 0845 051 5145

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