Vysa-Mat Classic heating mats rated 150W/sq m to 200W/sq m are normally required for use under tiles to be laid on top of concrete sub-floors to compensate for the heat flow into the concrete.
Even if Vysa-Pron thermal insulation is installed, (which we thoroughly recommend to minimise heat loss into the sub-floor), we would still recommend at least 150W/sq m rating and there is no disadvantage from installing heating mats rated 200W/sq m.
First check that the concrete sub-floor is sound and free from cracks, holes and projections. Repair the sub-floor as appropriate / necessary before proceeding.
Don’t forget to cut a channel into the floor for the 10 mm diameter flexible conduit for the floor sensor. The channel should be deep enough for the tube to finish sub-flush to the surface.
Insert the floor sensor into the 10 mm diameter flexible conduit and check that the red plug used to seal the conduit is in place to prevent ingress of adhesive or cement.
Install the flexible conduit into the channel cut in the floor and secure the remainder to the wall and wall mounting box for the thermostat.
Fill the channel in the floor with a 1:3 mixture of cement : sand or use a concrete leveller compound to make the floor smooth and level again.
Prime the floor with diluted Vysa-Bond PVA Adhesive, Sealer and Primer and allow to dry properly before continuing the installation.