Heating Film installs directly under a floating floor and is compatible with a variety of underlayment options. Simply lay out your underlayment and then position Heating Film above the underlayment. You can also install ThermoFilm under an MDF layer.Heating Film mats are then wired in parallel to a floor heating thermostat. The number of mats and layout of the room will affect the exact process of how to wire the heating mats together. Please see the Installation Manual for explicit directions or call us anytime for assistance.