I have two linked issues so I hope this thread is started in the most relevant topic area.   I have a terraced house built approximately 1890 which has evidence of damp in the Party Walls (it is mid terrace). There is also some damp present in non-Party Wall areas but they are not relevant to this thread. The damp is not horrendous and appears to be restricted to about 400mm upwards with evidence of salts causing "blistering" of the paint finish. I have had the property "surveyed" by a