Since the sub-floor is concrete, insulation is required for the project. Heating mat starts by the thermostat location. First row runs along the toilet (4" away from toilet ring), then five rows facing the vanity and the rest one and half row between tub and shower. Customer was advised carefully free cable from the mesh to cover the areas next to tub and shower, where heating mat cannot fit.
The best suited size of heating mat is: HTMATKIT-120-40: 20" wide x 24.4ft long and "Honeywell" thermostat.