Damp skim plaster on block wall

[dunner]

Hi all,
this is my first post , so forgive me if i waffle a bit .have spent hours on this site taking invaluable advice already to fit new shower tray & tile 3 sides ..but : i removed old tray in ensuite which was in corner between block wall & studwall .damp had set in & patch of skim plaster on block wall has crumbled away,rest of skimmed wall is ok . i believe its not great to tile onto skim plaster anyway so i need to prep block wall for tiling . i plan to tank shower walls with KERDI .whats the best way to prep this block wall for tiling?? should i remove all skim from wall , then dot & dab ordinary plasterboard & tank??if so whats best way to remove skim ..or should i use wood battens to fix new plasterboard to or should i repair skim,if so how ??
ta very much in advance .

 

[White Room]

What tiles are you fixing to the wall

 

[beanz]

How flat are the walls? I'd probably only strip the plaster back if the tiles are gonna be heavy (over 9mm thick). If the walls are flat and the only problem is the flaky plaster in the corner, i'd get all that off and fill with rapid set. If the walls are all over the shop, it might be worth the hassle of stripping the plaster off and boarding out with aqua panel, giving the tanking kit a miss.

 

[dunner]

thanks for d help lads , great site .
job's in my house & i haven't picked tiles out yet nor checked level of block wall & i have bought kerdi already, if i have to remove the skim coat , any better ways than banging wall with hammer ??

 

[White Room]

You say skim coat but on block walls there will be a undercoat as well???