A thin heating mat — thermostat, power cable, heat-trace wire and adhesive mesh — is laid directly over your waterproofing, bedded under a thin (~10mm) screed for even heat transfer, then tiled straight over the top. Every mat is tested before and after installation so nothing gets covered up unchecked. Running costs stay low thanks to a 6-segment programmable thermostat and a modest ~150W per m² draw.