Insulating concrete floor with limited height

[Doggit]

You haven't mentioned which top covering you're going to use. If it's with tiles, then no good without the UFH, as it's intended to stop the heat going downwards - and tiles damned cold with it, and really effing cold without it. If with wood, then it's fine without UFH.

Edit. Just noticed the previous posts. You'd need to use SLC or ply if you go for Vinyl, but if you go for post #14, then you don't need the membrane, as the old tiles tell you the floors okay.

 

[Gossamer]

You haven't mentioned which top covering you're going to use. If it's with tiles, then no good without the UFH, as it's intended to stop the heat going downwards - and tiles damned cold with it, and really effing cold without it. If with wood, then it's fine without UFH.

Edit. Just noticed the previous posts. You'd need to use SLC or ply if you go for Vinyl, but if you go for post #14, then you don't need the membrane, as the old tiles tell you the floors okay.

Was thinking tiles but yes they would be cold. A good quality wood floor might be good but I've got old sanded floors elsewhere so it might look a bit kack.

Has occurred to me that the original floor must have been screed for a reason. Perhaps a levels issue with the bathroom which was probably a coal store originally. Or maybe the original slab cracked. Makes me wary of breaking up the new slab tbh.

 

[Doggit]

I'd suspect it was more likely a difference in the height, but if the old slab were found to have cracked, then you'd just go a bit lower before rebuilding it. No real biggie, so I wouldn't worry about it.

You can get "new" distressed looking wooden floors to match believe it or not, and at least a wooden floating floor is a DIY job, or can you tile.