"rrh" wrote in message
...
I'm a bit confussed, but can't you just pack the 20mm with broken slate
tiles? I raise part of our floor that way. Jack up the joist with a
car
jack, put in the slate shimm and relax the jack.

Scott


Sure I could, but the point is that the wall around the fireplace area
hasn't just settled downwards a bit, it has developed a noticeable lean
out
of vertical. If I just pack onto the top of it, I'm worried that it will
collapse (at some future point when the floor is well and truly covered
with
expensive tiles...).

Ahh, now I have re-read your post and looked at the picture it has all
become clear. I would build a wall next to it as you suggest ie on the
side away from the camera. Use a few large breeze blocks so that the job is
quick and cheap - remember to put in a DPC. You don't have to be neat on
with the cement either, and it might be worth treating the wood too while
you're there.

Scott