How messy is plastering?

OddjobKIA

go and find NELLY he normaly hangs out in the arms

cargo

What is the sand for?

Just a thought as I have not heard this before and you never stop learning.

No it will not affect the ceiling as there is a lintel running across the front which forms the wall above the bay upto the ceiling.

If it is already plasterboard cut the board back to where it is firm and repair,best cutting back to a joist but you will have a bit of a job on bays as the joists are usually a bit of an after thought & tend to be a bit loose as some were pinned to the top of the original wooden bay windows and would have been moved therefore loose if upvc as been fitted.

Anyway just cut back to where firm and google on how to repair plasterboard patch without needing the joist.

This describes the method I grew up with.
but can be done with timber and screws nowadays.


http://www.ultimatehandyman.co.uk/PLAST_REPAIRING_HOLES_IN_PLASTERBOARD.htm

Supernova

OK thanks.

Actually, I think the plasterboard is fairly firm either side of a 1' by 1.5' patch so hopefully it is patchable. It sagged a bit from the weight of the water leak that caused the damage in the first place.

Any idea on costs for the work in London?

I was told plasterers would be £150 a day and that the patch would take half a day at most.

Or is it really DIYable?

Cheers