If the floor height is not important, then deviflex heating cables can be used. The typical centre to centre spacing is 100mm, ensuring that cold zones on the floor surface are avoided. The floor height will be around 15 to 25mm with a sand/cement screed.
When deviflex heating cables are to be installed, Devex Systems recommends the use of devifast fixing strips. The devifast strips are designed so that a cable spacing of 100mm can easily be achieved. The minimum bending diameter for a heating cable is 6 times the cable diameter.
It is also possible to attach the cables directly to light wire mesh with a diameter of 1mm and a mesh size of 50x50mm. The mesh sits on the sub floor structure and is covered during the screed process.
Another alternative is to glue the cables to the floor with a glue gun. If a thermostat with a floor sensor is used, the sensor must be protected by a plastic conduit with a minimum diameter of 10mm. The larger the diameter of the conduit, the easier it is to feed the sensor cable through it. The conduit has to be sealed at the end so that the concrete or moisture does not enter it.
If the cable or heating mat is laid on an existing wooden floor, it is necessary to ensure that the construction is stable even under heavy load. If a screed is to be installed on an existing wooden floor, a damp-proof membrane should be used in accordance with the BCA requirements.