Dreaded egg box walls

[chris.tiling]

Been to look at a job tonight and told the customers that the paint on the walls will have to be removed prior to fully tiling their bathroom.
The walls are egg box (unskimmed double layer of p/board with card box squares before another double layer of p/board) and the paint (they say) can't be removed. They also say that neighbours have the same and have fully tiled without issue. They are happy for me to tile but I am uncomfortable without removing the paint... Any ideas on how to do so without pulling the card off the plasterboard face?
Have suggested re boarding but that means narrowing the room down as the bath only just fits without bringing it in another 25mm

 

[pete f]

cut grooves down the wall and insert timber inside of the gap against the remaining board eggshell then fix board to it

 

[chris.tiling]

Cheers Pete, but they dont want to re-board the walls as mentioned above

Any ideas on removing the paint?

 

[DHTiling]

Paint on skim and paint on paper surface is different. IMO.

Simply slurry coat and tile.

 

[The Legend; Phil Hobson RIP]

Maybe worth searching paramount boards on the forums, there have been a few threads about it. Good luck.

 

[Qwerty]

How did you get on Chris?

 

[chris.tiling]

Not done it yet Geoff - they haven't booked me in yet as wanting to organise all other trades as well plus they are currently away