Help needed for internal wall

[snomys]

Hi

I recently stripped off my bathroom wall tiles, and the wall behind is in quite bad condition. A lot of craters, loose and crumbly bits and so forth.

I want to repair this, but I am unsure whether I should use a one coat plaster mix, or put a sand and cement base layer and a top coat on top of that.

The wall feels a little damp, cold, its an exterior wall on the other side, and inside, parts of the existing plaster is damp and can be picked away, there are parts which expose the underlying brickwork, which again feel a little damp.

I watched Tommys secrets on youtube, and he demos how to plaster a blockwall, but I think the mix used is just sand and cement.
https://www.youtube.com/watch?v=7cRGKh-UNxQ

Would this be stronger and have a great life than just adding a coat of plaster once again?

Can I add in some water-proofer additive of something so when the stream in the bathroom settles on this wall, it doesnt soak in.

Any advice greatly appreciated.

Thanks

 

[roy c]

Before you do anything ,identify where the damp is coming from and rectify it.!!

 

[snomys]

The wall is where a shower used to be, the wall was not properly tanked and would have been absorbing water for some time from the showers. This was completely unknown to me until I removed the tiles because I noticed alot of mould forming on the silicone and grout.

The previous workmen have simply used adhesive to stick plasterboard onto the wall, then tile onto the plasterboard. For a wetroom I know this is not enough. I have got the dehumidifier in there going non stop and dont intend on doing any rendering until the wall has dried out a fair bit.

 

[ree]

As above.

If this is a concern then why not take the trouble to post some pics of the bathroom interior and the outside wall surface?