Attach Plasterboard to old Tiles

[Mudbream]

Hi,

I'm new here and about to embark on my first big DIY project - redoing the bathroom!
I am wanting to put plasterboard over the old tiles in the bathroom and then I'll be re-tiling over it.
There is a small ledge of about 20mm halfway up the wall where the plasterboard will be able to rest against.
What is the best way to attach the plasterboard to the wall so that it will be fixed firmly enough to hold tiles or a large mirror?
The area being done is approximately 1800mm x 900mm.
Also, does the plasterboard need to be treated to ensure that it will be waterproof?
Any advice here would be great!

Thanks,
Mudbream

 

[masona]

No need to put plasterboard up, have a read here

 

[Mudbream]

Ah sorry. The reason I want to put plasterboard first before tiling is that there is this ledge halfway up the wall. So the bottom half of the wall is about 20mm further out than the top half. I want the entire wall to be flat.
I have no idea why there is this ledge, but I don't want it, which is why I want to put plasterboard first as this, along with the tiles, should get the walls almost even.

So I will need to put up plasterboard first - unless someone has a better idea of how this should be done?

Thanks

 

[masona]

I would use the dot n dab adhesive method, and when fixing the mirror make sure you use longer screw for the rawlplug in the back wall area so the mirror fixings is not hanging on the plasterboard.