The severely weathered brickwork in this photo shows an extreme case of rising damp.
This is an old building. It may have been constructed without a damp proof course (DPC). If there is a DPC it is clearly defective.
The dampness will be spoiling decorations and plaster internally and could have resulted in an outbreak of wet and/or dry rot.
Early repair is needed. It will be disruptive and costly to deal with. Specialist contractors must be employed. Ensure you get a comprehensive guarantee for any such work undertaken.