We have an old style terraced house which normally has a breast wall which accounts for the chimney; either side of this are two alcoves that are set back perhaps half a foot. The dimensions of these alcoves are about 1.5ft wide by 10ft tall.
In one half of our room, these alcoves have been bordered up to provide a surface that's level with the breast wall. This was fully wallpapered.
As we've been stripping the wallpaper off this wall, the plaster layer on one of these alcoves has crumbled off leaving us with bare plasterboard underneath. This is about 1mm deep. What can be done in this situation?