TheScullster wrote in message ...
To get my bath to fit, I have channelled into the plasterboard itself on
one
wall.
I am concerned about ingress of water in the event of a leak and total
destruction of the plaster board.
How should this be sealed before tiling?
The chanelling shouldn't make any difference. Plasterboard has no water
resistance and can't be sealed in any meaningful sense of the word.
You have to rely on the tiling for that.