Tanking bath area - how to do this with just a bathtub already there?

[Suzan]

Hi all,

Took down some old tiles in my bathroom and plasterer came round to plaster the walls with gypsum thistle bond plaster, was going to plaster myself but it would have been the first time so i thought i'd watch someone instead - i know this plaster is not good when it comes to water (from what i've heard) so, even though i won't be using it as a shower as such, i thought it best to tank the bathtub. Thing is i can't (don't want to <.<) take the bathtub out from where it is, and the plaster has dried. I bought a kit from screwfix called Mapei shower waterproofing kit, and I wanted to lay down the tape along the vertical wall joints, and preferably the bath lip but don't think i can properly get behind it...

Any advice? I've attached a picture of how it looks ATM and the stuff i'll be using - any advice would be appreciated as the plasterer said to use PVA but i've heard this isn't a good thing. My tiles are 16kg per sqm and adhesive+grout will come to 4kg per sqm (i think 20kg per sqm is the max for plaster anyway...).

Thanks!
Suzan

Here's the link to the pictures Imgur - https://imgur.com/a/TeGis

 

[Bill]

Bonding is no good for tiling onto - at least the plasterer should have skimmed it.

Call your plasterer and ask for a refund on his advice or at least his workmanship (change gender appropriately)

 

[Suzan]

Underneath there was normal plaster but because the old tiles had damaged part of it, that's why he used that plaster. I wouldn't get a refund in a million years from that guy... What options do I have?

 

[Suzan]

When taking down the old tiles, I noticed the first layer was smooth grey, then sandy plaster, then behind that was what looked like some yellow paper of some sort and then some greenish board of some sort...

 

[Suzan]

Obviously that's when he put the thistle bonding on top knowing I want to tile..

 

[Old Mod]

As Tom States, as it is, the surface you have is not suitable to be tiled.
Sounds like the wall was a bit of a mess, do you have any images of before it was bonded out?
So it’s a boarded partition wall, not brick?

 

[Suzan]

Imgur - https://imgur.com/a/KEcWm
This is before the thistle bonding he put on. He is still insisting when I message him that you can but I told him even British gypsum tell you not to. I spent 260 on that plaster job which I didn't really have so I'm upset... And the next thing I do is something I'll have to do. I'm pretty DIY savvy, just didn't take the job on as I was worried I wouldn't get it flat.

 

[Suzan]

He told me he only did one towelt with of it... If that makes any difference...