Hi I had damage occur to a bedroom wall as some water came through a window. The window has now been fixed so I’d like to restore the wall. The water caused some damage to a section of the paint as well as a thin (1 or 2 mm) white smooth layer underneath the paint which sits on top of the render. The white layer has fallen off in some sections. I think it is plaster which is smoothing out the rougher render underneath. I would like to repair the white layer so that it sits flush with the rest of the wall ready for painting. I was wondering what the white layer is and how I should go about it?

