[RCTA3]

I live in middle east, dubai to be exact. Im trying to fix my wall from moisture damage. I scraped most of the peeling part of the paint and white plaster with water discoloration. But there was somewhat a 3rd layer which is like a sand in texture. I tried poke it and its about more than an inch thick before the concrete.
Now, id like to repair it so i bought a plaster and paint. Any tips on application? Because i am having doubt that the plaster i have wont stick on the sandy matrial on the wall

 

[mark sr]

I've always primed exposed brown coat when I was worried about adhesion. I should note I'm a painter, not a plaster guy and whenever I'm roped into repairing plaster I use Durabond instead of plaster - because I know setting compounds and don't have experience applying plaster.

 

[ClarenceBauer]

I don't know what products are available in the Middle East but if the Plaster product states that it is a Gypsum or Lime based product it will adhere to the sandy brown coat.