A friend of mine has a flat built around 1990 I guess. It was built with electrical ceiling heating (don't ask me what they were thinking of). He's had gas central heating put in and ditched the ceiling heating. The problem he has is that his living room is always too cold in the winter. It's quite a large room, and at a quick glance I would guess that the rad is inadequate for the heat loss. He could just upgrade the rad. But the real problem seems to me that the concrete floor of this room is probably not properly insulated. He complains that the floor always seems cold in winter.
The room is on the first floor, but underneath it is just an outdoor space used for car parking which is completely open to the elements. I don't know what insulation they put in when they built it, but I reckon some celotex screwed to the underside (ie the "ceiling" of the parking area) would be a help. Any thoughts on this? What should he screw over the celotex - there's no chance of rain hitting it directly, so would normal plaster board do, or is there some sort of exterior version?