Underfloor heating on wooden beam ceiling

Hello "ShawN46". Basically, such a structure is conceivable, but you have no height to spare! 10mm are 10mm, and the thermal insulation effect of a 10mm thick wood fiberboard is so insignificant that the height should be used more sensibly. The thermal insulation in an unheated basement must absolutely be applied to the underside of the ceiling!! What you have temporarily exposed there is known as a "Preußische Kappendecke" and was a commonly chosen ceiling variant in the 1930s. Quite load-bearing, but due to the iron beams structurally an insane thermal bridge. I still had "in my ear" that underfloor heating was to be installed? To cut it short here: Currently, I have taken over the planning of the floor structure for 2 large projects of up to 6,700 sqm floor area each, with respectively limited load-bearing capacity of the ceiling constructions in Frankfurt and Berlin. Maybe I can give you one or two tips if you tell me the requirements your floor must meet. Here, in addition to the load-bearing capacity (kg/m²) of the ceiling, the overall available height and the type of floor covering are also required. Regards: KlaRa