Hi guys, I just finished peeling off all the wallpaper and gum from the walls in this bedroom. House is an old 1950's built, with concrete brick on the outside and mud brick in the inside. Can any of you tell me what is the orange thing that is peeling off the wall? it is the undercoat? It was under the gum and some of it came off but some stayed.In the other side of the room you can see that there is less of that orange paint and more of the white one which is the same layer but in different colour. What were they trying to do when they put the wallpaper? In one of the pictures you can see the brick, what kind of plaster or render is this? Can I use a normal filler to cover it? I have read that old plasters are made of a different materials and the new ones won't stick? What is the best course of action for me to fix this before I paint?