Floating wooden floor over concrete terrazzo tiles

[Rosemouse]

Hello! I have an early 19th century stone house in France, and it has a nice, well-ventilated cave with stone walls and dirt floor which sits below the kitchen and living room. The living room has oak boards which are reasonably warm, but when the house was extended in the 1930's, the owner installed concrete terrazzo tiles in the kitchen - and that floor is FREEZING. Although the terrazzo tiles are part of the character - there was a fantastically beautiful staircase added at the same time, a second storey was put on, and other marbled concrete tiles line the entrance way - the terrazzo tiles in the kitchen are pretty ugly and look like school flooring.
What would be the constraints of potentially installing an insulated floating wood floor over the kitchen floor and making it a step up from the loungeroom - with which it will eventually be open plan. The part of the house is not touching the ground - there is a well-ventilated and dry cellar beneath this level. But is there anything I should consider about heat/cold exchange or humidity? Beneath the concrete the ceiling of the cellar has been done traditionally in mud and straw whorled plaster - twisted around small oak rods and fitted between beams which would have originally been wood but in the 1930's were replaced by steel girders (owner at this stage was an airplane mechanic for the nearby American airbase and was completely at home using all the latest materials!).
I am still in a steep learning curve with this house and would be delighted if anyone could offer any advice as to how to make this floor warmer and less ugly - my other option I guess at great expense would be to remove all the concrete terrazzo and replace with either traditional terracotta tiles or wood planks.
Thank you for reading this far!

 

[aockenden]

I’d be a little wary of putting a wood floor on-top of cold, solid, cement tiled surface even despite the ventilated cellar directly below… sounds like a recipe for trapped condensation. Especially as this is a kitchen where humidity / internal moisture levels will generally be higher. That ventilation in the cellar beneath the kitchen won’t help to evaporate condensation that has been trapped between the top-face of the cold cement tiles and the wooden flooring.

I think the risk of trapping condensation would be reduced if the flooring was old school gappy style butted edges without tongue and groove or half-lapped joints to close off the gaps. Those gaps would provide lots of escape outlets for condensation back upwards into the kitchen, but modern people tend to hate that gappy look…

What do the existing concrete tiles sit on top of currently?