I have got the underfloor heating down and am at some point in the future going to cover with engineered wood floor. I am having some stairs made and need to tell the guys who are making the stairs what mill the floor will be so it will fit underneath . I have been to various floor places and the information differs fron 20 mill beech backing flooring and 14 mill birch backing at living floors . Does anyone have engineered flooring down on underfloor heating that can tell me what theirs feels like under foot depending on what mill they have Thank you