How To Install My Undertile Floor Kit

Do the prep work

Step 1: Draw your room with dimensions

Make sure you measure the size of your vanity, shower, toilet, wardrobe and other fixed elements to assist in your calculations.

Step 2: Decide on the position of the thermostat

Decide where to place the thermostat. Remember that the floor is controlled using a floor sensor, so you can place the thermostat inside a cabinet or wardrobe if you want the thermostat to be hidden. However, if the sensor fails and cannot be replaced, you won't be able to control the room temperature by changing the thermostat to air sensing, if it is placed in a cupboard.

Step 3: Make a plan on how to lay down your heating mat

Your heating mat needs to start close to the thermostat conduit location. The Devimat comes with one cold tail, which your electrician later connects, along with the floor sensor, to the back of the thermostat. The cold tail is thicker than the heating cable so it is important to have the start of the mat as close as possible to the thermostat conduit to minimise the cold tail runs inside the glue bed. Note that the join (termination) between the heating cable and cold tail must be in the glue bed, not in the conduit or wall cavity.


Case study 1: Bedroom

  • Start the mat near the thermostat.
  • Finish the mat near an unheated surface (like the built-in wardrobe) so that if you have excess cable, you can lay it down there. However, we recommend to undersize your heating mat in the first place to avoid this situation.

This picture helps you understand how to connect two long runs:

Case Study 2: Bathroom

  • The bath is a free standing bath, so it is a good idea to heat the floor around the bath.
  • The vanity is floor mounted. If the vanity was wall mounted, it would be better to heat up to the point the feet can reach (similar to the free standing bath).
  • Pay extra attention to the position of the cables near places where you are likely to stand, such as in front of the vanity, near the toilet or near the exit from the shower where you dry yourself. It is important to keep the spacing of the cables as regular as possible, making sure they are not touching each other or overlapping; otherwise, you could experience hot or cold spots.

On the following picture, you can see how to fill gaps by cutting the fiberglass mesh. You can also see how non-heated surfaces are highlighted:

Step 4: Ask your electrician to install the conduits

When your electrician comes to do the wiring for the light switches, ask him to place two 25mm rigid conduits in the wall from the thermostat location down to the floor (this conduit is not included in the Mat Kit as it should be part of the standard consumables of your electrician). One conduit is for the mat cold tail and the other is for the floor sensor. The rigid conduits will make it easy to insert the cold tail and the sensor after the walls are sheeted. Note that for larger areas (over 12 sqm) where several mats are needed, you would need as many conduits as there are mats, plus the one for the sensor.


Start the manual work!

Step 5: Connect your heating mat to the DIYSafe

You only need a small screw driver to be able to wire the heating cable to the DIYSafe alarm. Check this document for more details.

Step 6: Lay down the heating mat

This is the fun bit. Please refer to this document for more tips and tricks.

Step 7: Install the flexible black conduit and the sensor probe

This conduit is the one included with the kit (not to be confused with the cold tail conduit we previously talked about). This conduit (with sensor probe) needs to run from the thermostat down one of the 25mm conduits installed by your electrician into the floor.

On the following picture, you can see how all the cold tails goes back to the thermostat. You can also notice the DIYSafe hanging up the wall. Note that this is a very large areas, hence the need to connect multiple mats to the same thermostat:

Step 8: Install the thermostat

Note that this is the only step that you can't do by yourself, unless you have an electrical license. However, any electrician can easily connect the thermostat, let him know when he/she wires the light switches.

Step 9: Program your thermostat

Once the tiling is complete and all the wiring is done, you can start your heating system to feel it working. Programmable instructions can be found here.

Step 10: Enjoy