Hi, i own an first floor flat (circa 1900) and have noticed some blistering on some of the kitchen walls (internal) as well as on the hall wall (the room which shares the kitchen wall)
Hopefully the image link above works. The blisters are very dry and will crumble if poked. None of the walls feel damp. The bathroom is close by if that makes a difference.
Any ideas would be gratefully received, as well as any guidance on how and who could rectify my problem.