I want to instal a 14mm engineered oak floating floor in my lounge with electric UFH below. The existing floor (concrete, and reasonably flat) is approx 55mm below the adjoining room so would like to bring it up, close to that level, with Insulation. Can I simply use 25/30mm of high density insulation, followed by a membrane, UFH and 14mm engineered oak, or will I need to use less insulation (10mm) with 18mm floorboard, followed by membrane, 5mm sound insulation, UFH, 14mm engineered oak?