I have a damp patch on the interior wall situated 2 metres up from floor level. The internal wall shows no other signs of damp. The house is a mid terraced house built in 1899. The rear exterior wall shows signs of salts bubbling through the cement render/masonry paint. The damp patch is situated on the interior wall between the door access to the kitchen and the ground floor window. The interior wall on which the damp patch is located on what would have originally been the external wall but the kitchen extension wall (kitchen extension single brick erected circa 1970's) incorporates this section of the exterior wall making it an interior wall and not subject to direct weathering. I don't know whether this damp patch would be classed as "rising damp" or "penetrating damp" possibly from a loose roof tile or a crack in the external wall. Is there anyone here who could advise me please on how to eradicate this damp patch? (photos attached)
its not rising damp,Cant see the pictures that well, but if its by a window there is usually an external crack causing the damp to penitrate.Or its a bridged wall tie.Fill in any cracks with a clear silicone and spraying the external wall with a silicone based solution like aquaseal .
Thanks Welsh brickie! I appreciate you're advice. I'll have a good look at the exterior wall as soon as the weather stays dry long enough. If as you say its a breached wall tie how would I rectify the problem? I'll do the exterior checks for cracks etc first.
if its not a crack any other problem you can see,Then you can hire a borescope.You drill a hole by the damp patch and insert the probe to see into the cavity. Then if it is a bridged wall tie causing the damp you will have to make a hole in the wall and knock it off.
I see, that sounds like a major bit of work. I'managed to seal the obvious cracks in the wall with clear silocone. I also resealed the window and back door too. I haven't used aqua seal yet as I wanted to give the sealant time to go off - and guess what! It's raining up in North Lancashire again! As I said in my original post the house was built in 1899, is the wall on which the damp patch has appeared likely to be rubble filled? Also the brick built 1970's kitchen extension ties into the original exterior wall so I suppose it's at that point the wall tie investigation should start?