Problem during prep for re-grouting

[asinine]

Not sure if I should be posting this in the plastering forum or here apologies if its in the wrong place.

My problem is that I had a leak from the plug in my shower which I sorted but whilst doing this found another leak coming down from between the shower basin and the plasterboard.

The previous owner of the house was obviously a cowboy! Rather than fixing the grout they had used sealant to seal it. Anyway I decided to regrout the shower to stop the leak and at the bottom of the shower where the leak was as I was removing the grout the tiles started to come off. Only six along the bottom. The rest of the tiles are still on solid above these and to the sides and the plasterboard is dry above this area.

I have cleaned the tiles up. What I'm thinking of doing is letting the plasterboard dry out which is damp but not crumbling and reapplying them.

My questions are is this the thing to do? I really can't afford to re-tile the shower

If it is do I need to prime the plasterboard to make it water proof? And what with etc etc.

Also a wee question about hte re-grouting. Does it all have to be removed? ie to good and bad stuff?

Thanks for the help guys.

[tictic]

The plasterboard won't dry out...it's knackered,...strip and redo..me thinks...or take the tiles off till about 1m above floor/bath level and see how the p/board is ...if ok then patch in with a cement backer board.