Our house has a gas boiler that feeds the radiators in the basement and underfloor heating on the first and second floors in two heating circuits. I have a converted office room (about 18 m2) in the basement (the basement is 50% underground). A radiator is installed here. The room gets warm, but the floor (tiled) remains quite cold. My question is: Is it possible (or does it make sense) to install a warm floor here? Or are there other ideas for cold floors in the basement?
Subsequent milling is always a possibility if the screed is >4 cm and the screed is suitable. Much more important, especially in a basement, is whether the floor is sufficiently insulated from the ground. Alternatively, you could consider an electric heating system under the flooring as a support. Replacing tile with carpet or PVC, etc. would also help.
There is ultra-thin insulation material, and you can lay parquet on it.
If you still need something, you can build an infrared module on the ceiling, for example; then it will heat the floor. I think that would eliminate the need for a radiator, which also consumes energy.
Expanding the underfloor heating system is definitely a big and expensive undertaking, and if you can't insulate it from below, the energy also goes down the pipe.