ID-ing damp in a house that's never been properly heated.

[super98]

I'm starting a wee project in a 1900s red brick terrace that's never been centrally heated. There's been individual gas fires fitted in the rooms, but presumably the poor old boy before me just used the one in the room he was in.

On the morgage report there was "evidence of rising damp" and indeed the bottoms of several downstairs walls had stained plaster + rotten skirting boards. There is a bit of a tide line on some walls too.

Chipping some plaster off and removing skirting, the bare brick looks ok and not wet, so how am I supposed to diagnose any rising damp? Is it just condensation from being mostly unheated?

 

[super98]

Picture of one offending wall, tide line just visible a couple of feet up.

 

[jeds]

Ideally you would test with a 'speedy' carbide meter but they're expensive and I don't think you can hire them? You could try a salts test kit. That will tell you if the walls/moisture contains any soil borne salts. If no salts are detected then you know the moisture came from elsewhere - i.e. condensation. The last time I bought a kit it was about £50 ish.