Damp hiding suggestions please!

[Zachl]

For facts sake:
Foam will not wick water near as much as gypsum based adhesive

That does not mean you can foam a board on and problem solved
I think @Dollar is on the money (no pun intent)

Battening an uneven wall is not much harder than battening an even wall just a case of packing it out where needed which is extra faff but not really extra work - it can be quite satisfying?

If render on outside has sbr in it then water can’t escape externally and if you batten and DPM/VCL inside the water can’t go inside wards either your wall would become like a massive tampon and when they are full they leak somewhere.

Thanks mate

 

[Zachl]

Can't believe you are still asking us to conspire to deliberately hide a big defect and defraud a housebuyer.

If it is as bad as you say then it will cost so much to fix that the insurance company if not the new owner will come after you in the courts.
Then your lawyer will try to say you're a poor innocent and relied upon advice from this forum.

Bet you're fun at parties

 

[Scot22]

I'm with Brimstone. Don't do anything that you would not like doing to a property you were buying. You appear to want to deceive a buyer.

This is not a case of caveat emptor.