Wet room set 8x Backer Boards + 5 m² Underfloor Heating

See parts included Technical specification

Backer boards insulation kit with electric underfloor heating set. If you want to use electric underfloor heating on a wooden floor, you must first cover it with backer boards. The boards will guarantee a sturdy, even surface that will adequately insulate the floor and reflect the heat inside the room. After using the boards, you can safely stick the mats and cover them with tiles.

£415.54 £461.71 -10%
Tax included


Underfloor heating insulation kit contains of 5 m² (50cm x 10m) heating mat and 8 cement coated building boards (600 x 1200 x 6 mm) – Used for creating a waterproof surface suitable for fixing tiles. These two products make an easy to install set in any bathroom that can be your main or additional heating system.

The Sunfloor heating system can be used in selected area (for ex. just under the shower) or in the entire room. In either case it heats up the floor quickly. It is compatible with our Showerlay XPS boards and drains. Thanks to the XPS boards insulating properties the shower floor heating is very effective and cost efficient. 

The mat can be cut and laid in various ways. Just make sure to cover with it only usable are, not under furniture and appliances. 

Cement coated building boards – Used for creating a waterproof surface suitable for fixing wall and floor tiles. Manufactured to the highest specification, Imperboard is the benchmark for stable, impervious and durable tiling boards. There are many areas of application including uses in showers, steam rooms and swimming pools. Versatile – Suitable for use on metal and timber stud work, or on existing floors and walls to cover unstable and uneven surfaces. 

Imperboard is made from a high-performance waterproof extruded polystyrene, coated with a glass fiber mesh and polymer cement mortar.

If you buy this product you will receive (parts included):

  • Heating mat with connecting wire,
  • Thermostat,
  • 8x Tile Backer Boards (600 x 1200 x 6 mm)
  • Floor sensor,
  • Flexible sensor tube,
  • Inspection card,
  • Installation instructions.

If you need different amount of boards or heating mats please contact us.

Board coverage
5,76 m²
20 mm
600 x 1200 mm
Compressive Strength
300 kN/m2
Resistance to soft body Impact load
3 x 120 Nm
Working Temperature Range
-50 to +75 c
Fire behaviour
Class E
36 kg/m3
Pack quantity
8 pieces
Pack coverage
5,76 m²

Dear Client

This heating product is manufactured from high quality, durable materials. To guarantee that your product functions optimally there are a few points of attention which are described in the Installation Instructions. We can only offer you the full guarantee if the system is correctly installed in accordance with these Installation Instructions. Carefully read the instructions prior to installation, do not forget the centre page when doing so, and ensure that you have the correct tools and materials. The electrical installation must be carried out by a qualified electrician in accordance with current local regulations.

1. Check: Check the contents of the box before starting. A complete set consists of:

  • Heating mat with connecting wire
  • nspection card
  • Thermostat incl. floorsensor
  • A flexible sensor tube
  • Installation instructions

2. Measurements:

Product Size Power Amp Ohm
SUNFLOOR Mat 1 m² 50 cm x 2 m 150 Watt 0.7 353
SUNFLOOR Mat 1,5 m² 50 cm x 3 m 225 Watt 1.0 235
SUNFLOOR Mat 2 m² 50 cm x 4 m 300 Watt 1.3 176
SUNFLOOR Mat 2,5 m² 50 cm x 5 m 375 Watt 1.6 141
SUNFLOOR Mat 3 m² 50 cm x 6 m 450 Watt 2.0 117
SUNFLOOR Mat 3,5 m² 50 cm x 7 m 525 Watt 2,3 100
SUNFLOOR Mat 4 m² 50 cm x 8 m 600 Watt 2.6 88
SUNFLOOR Mat 4,5 m² 50 cm x 9 m 675 Watt 2.9 78
SUNFLOOR Mat 5 m² 50 cm x 10 m 750 Watt 3.3 71
SUNFLOOR Mat 6 m² 50 cm x 12 m 900 Watt 3.9 59
SUNFLOOR Mat 7 m² 50 cm x 14 m 1050 Watt 4,6 50
SUNFLOOR Mat 8 m² 50 cm x 16 m 1200 Watt 5.2 44
SUNFLOOR Mat 9 m² 50 cm x 18 m 1350 Watt 5,9 39
SUNFLOOR Mat 10 m² 50 cm x 20 m 1500 Watt 6.5 35

3. Points of attention:

Check before hand if the heating mat is the right size for the floor area to be heated and that there is sufficient electrical capacity (Amps.) available. Before installing the mat, the resistance reading should be taken and noted down on the inspection card in the center of this manual. (See point 7).

The connector cable can be extended or shortened, there must always be at least 0.5 meter of connecting wire left. The heating cable, attached to the glass fibre net, cannot be cut. The mats cannot be laid over each other and the heating cables may never cross each other! The cable junction (SPLICE) is the transition of the resistance cable (heating section of the mat) to the power cable (cold connection) is just within the heating mat and is marked.

A distance from the wall of 10 to 20 cm should generally be adhered to. The Heating mat may never be installed under fixed objects like wall units, kitchen units, baths, or showers and must be able to give off its warmth unimpeded. The Heating mat may only be incorporated into the free floor areas. As bathrooms consist mostly of a small free floor area the mat can only be installed as supplementary heating. Please contact your local supplier for information about use as main heating.

All installations must be wired through a suitably rated MCB or RCCD when applicable. All installations in wet areas must be wired through a dedicated  RCCD in line with the thermostat. All connections must be made by an approved electrician in accordance with current local regulations. The Heating mat is 3 to 4 mm thick and must be incorporated in a flexible adhesive or casting mortar suitable for floor heating. Check the manufacturers data.
The Heating mat has 1 connecting cable 3.5 meters in length (Twin Conductor) and has an end seal (loop) at the end of the mat. The end seal CANNOT be broken. The connector cable can be shortened, there must always be at least 0.5 meter of connecting wire left. The power supply must never be connected during installation. If multiple mats are installed in a space, they must be wired in parallel and a suitably rated junction box may be incorporated so that only one power cable runs to the thermostat. Maximum capacity of the thermostat is 16 Amperes. If combined area exceeds 23m², a Contactor will have to be fitted. The thermostat may only be installed by a qualified electrician. The sensorcable can be extended or shortened. The sensor must be installed in the middle of a cable loop for optimal temperature registration. Ensure that the sensor is installed well clear (min. 50 cm) of (hidden) radiator and water pipes, drains and electrical wiring. The sensor must always remain IN the sensor tube. Fit cap to end of the sensor tube. If the sensor ever needs to be replaced it can then easily be removed.
The Heating mat is primarily designed for installation on concrete floors. If laying on a wooden floor, all floors must be sheeted with a cement faced board which is compatible with heated floor systems. Or sheet the floor with 15mm WBP or Marine plywood, fix with screws at 200mm centres and then skim with 2-3mm of flexible tile adhesive and allow to dry, then proceed as installation for concrete base.

4. Necessary materials:

  • A SUNFLOOR Mat System.
  • Flexible tile adhesive or Self levelling compound and flexible grout suitable for floor heating.
  • Flexible cement and cement gun for expansion joints along the walls.
  • Approx. 2m flexible electrical conduit (16mm)
  • (Plastic) adhesive comb with approx. 6mm teeth.
  • Electrical back box (min 35mm deep, prefer-ably 50mm).
  • Earthed power connection.
  • A multimeter to test the mat after each installation activity.
  • various tools.

5. Preparations:

Determine where the thermostat must  be placed, place a standard electrical back box with a minimum depth of 35mm, preferably at a height of 1.40 m for ease of operation. Grind/cut the necessary grooves and mount the junction box and electrical conduit. 2 conduits have to be installed; One for the sensor and the other for the power cable from mat. Do not run the power cable and sensor cable through the same conduit. Cut a groove in the floor for the floor sensor pipe (2 cm deep).

TAKE CARE: Never place the sensor in the vicinity of a (hidden) radiator pipe! Never install it passing under a heating cable!

Ensure that the surface where the mat is worked on is flat, clean, and free of dust and grease. In larger spaces, expansion joints along the wall may have to be used.

Sunfloor underfloor heating installation

6. Resistance readings

Before installing the Heating mat, the resistance reading should be taken and noted down on the inspection card in the center of this manual. The reading should be taken during the installation and on final completion. These readings should be as per the technical information (Point 2). Take measurements both between the resistance wires and between the resistance wire and the earth cladding.

Keep this inspection card in the meter cupboard in a visible place! This forms part of your guarantee.

7. Measuring out the mat:

Allow for a distance from the wall of 20 to 30 cm when rolling out the matting in larger areas. This does not apply to glazed walls where extra heating is required. If the SUNFLOOR Mat is to long, the mat can be cut into a long length and laid round the periphery of the mat. The loose cables must be looped at least 5 cm from each other. They may not touch or cross each other. Retest the mat when it has been laid.

8. Tile cement method:

Unroll the heating mat with the heating cable down so that only the glass fibre netting is visible.

  • Position the mat as described in Point 7.
  • Take the resistance readings.
  • Pull the end of the connecting cable through the electrical piping to the thermostat.
  • Apply the first layer of Flexible tile adhesive
  • 0,4 cm to 0,6 cm thick and approx. 55 cm wide.
  • Roll the mat out over the tile cement with the cable facing downwards.
  • Softly push the mat down with a wooden spatula or gloves and spread the tile cement that oozes through the mat.
  • Smooth it over and allow it to dry.
  • Take the resistance readings of the mat again.
  • Then apply a second solid layer of flexible tile adhesive taking care to avoid air bubbles and use a plastic tile cement comb to avoid damaging the mat. (DO NOT SPOT TILE!).
  • Press down the tile with a light sliding motion.

Sunfloor underfloor heating installation

10. Self-Levelling method:

Unroll the heating mat with the heating cable facing upwards.

  • Position the mat as described in Point 8.
  • Pull the end of the connecting cable through the electrical piping to the thermostat.
  • Take the resistance readings.
  • First read the instructions of the self-levelling mortar, check that the product is suitable for floor heating and follow the instructions of the manufacturer to the letter.
  • The self-levelling effect must usually be assisted somewhat using a squeegee. Observe the drying time before applying the floor covering.
  • Take the resistance readings of the mat again.
  • Then apply a solid layer of flexible tile adhesive taking care to avoid air bubbles and use a plastic tile cement comb to avoid damaging the heating mat. (DO NOT SPOT TILE!). Press down the tile with a light sliding motion.

TAKE CARE: Do not apply more than 1 self levelling layer. Please follow manufacturers instructions. 

11. Connecting the thermostat:

Installation needs to be done by a qualified electrician in accordance with all current wiring and building regulations. Before installation or re-installation of the thermostat always isolate the power to the thermostat.

To install and set up the thermostat, please use the manual that is included with the thermostat.

13. Using the system for the first time:

Depending on the drying time specified for the Flexible adhesive or self-levelling compound, however not sooner than 21 days after installation due to the natural expulsion of moisture from the floor.

Turning on the system sooner can damage the floor.

Documents available below are available to everybody for free to download. They can be open in high quality on your computer and be printed for further use.

Sunfloor Heating Mat manual WiFi Thermostat manual

ufh mat
Complete Underfloor Heating Kit
It is possible to include a complete Underfloor Heating Kit to your order. All you need to do is to choose the required size. Additional package, with heating mat, appropriate thermostat, sensor and instructions will be dispatched together with the other goods.

To calculate required mat size you need to get square coverage of the floor and exclude any permanent / fixed fixtures from them. It is also recommended to buy slightly smaller mat than calculated size - you can shape it but cannot cut the cables, therefore too large mat could not be installed.

SUNFLOOR Underfloor Heating
The SUNFLOOR Electric Heating Mat is a unique type of floor heating mat. The system has been designed to be used on an existing tiled floor or an existing finished floor, so that floor heating can still be installed there. The mat is approximately 4 mm thick and can be included in a layer of adhesive without any demolishing or grinding. The mat fits virtually underneath the surface. This decreases the heating time of the floor, that also makes this system suitable for rooms that are not permanently occupied including bathrooms, studies, playrooms, etc.

Heating mat
Underfloor heating mat set consists of all necessary parts for installation. One Thermostat is needed for every 23 m² of heating mat. It is included as optional, to allow ordering mat for custom areas, for example if you need 13 m² of mat total, you should buy 10 m² with one of the thermostats set as include and 3 m² with thermostat not included. In case you require less mat coverage than possible to buy from our product pictures, for example 14.5 m² you should always round low with your purchase and buy 14 m² as the mat is impossible to cut. It can be shaped but not shortened to size.

  • 2.5 meter 3-core supply cable
  • Fully encased in an aluminium earthed sheath
  • Unique blind connection between the heating and the connection cable
  • Chrome/Nickel resistance wire
  • PTFE (Teflon) insulation
  • PVC protective sheath
  • 10 -11 watt per meter resistance wire, 230 Volt
  • Cable diameter approximately 4 mm
  • Complies with current NEN standards for installation in completely wet rooms
Smart Sunlaser Thermostat
The C16Wi-Fi is an intuitive programmable thermostat used to control the electrical floor heating system or water heating system. It will keep home comfortable temp whilst minimizing energy use. Install the app on your smartphone to control the heating system remotely with the WiFi thermostat.


  • Voltage: 85 – 265 Vac 50/60 Hz
  • Standby power: <1 W / 2 W (WiFi version)
  • Max load: 16 A (electric heating) / 3 A (water heating)
  • Frame: IP21
  • Color: White / Black
No reviews
What are your office opening hours ?Are you open on an Saturday please ?


We are not working during weekends, sometimes we do reply to emails and phone calls.

You can visit our Rotherham warehouse from Monday to Friday, 9am - 6 pm.

Let me know if you have any questions about our products or service.

Kind regards

Adam 017 0927 3601

Do you sell the tanking liquid separately?


Yes, tanking liquid is available separately, however it's less cost efficient. Waterproofing kit is available at comparable price and contains materials that you will probably need to use anyway.

There's special category in our store: Tanking liquid.

I am happy to assist if you have any further questions.

Kin regards

David 020 7193 0953

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