The floor removed. Now, what remains it the most problematic part - under that cupboard there are water- and sewer pipes, both sealed inside a block of concrete. I will keep most of that concrete, but I need to see if there is a gap in between the concrete and the wall. It would be easier to do that if I'd disconnect the water, but that would mean some trouble for my daily life. So I will try to figure out a way to work near the water- and sewer connections while they are operational. (The thing is; the water is connected to the tap which is mounted on the sink top of the cupboard. Destroying the entire cupboard would require disconnecting the tap, and that can't be done while there is pressure inside the water pipeline... Well, I will go have a sauna bath and think about this tomorrow.)