I've just moved into an old flat that has been subject to some movement
in the past. As a result, there is a fairly significant slope in one of
the rooms. I've not properly measured the slope, but it equates to a
height drop of a couple of inches over a metre or so.

I'm evaluating a couple of ways of fixing this. The most "pure" one
strikes me as being lifting the boards, packing the joists until level,
and then relaying boards.

Alternatively, someone has mentioned building a "false" floor on top of
the existing boards. Basically, adding new joists to above the boards,
then laying a new set of boards, basically giving a whole new floor.

Finally, someone suggested to me that some self-levelling floor
compound could do the job. This does strike me as an easy option, which
consequently make me very uneasy about it! Does anyone have any
experience of using this stuff to level a floor? I'll be laying carpet
on top of it eventuallly, if that makes any difference.

If anyone has been through the joys of doing this in the past, I'd be
most grateful to get some thoughts and wisdom!