Damp. Seems too high for rising damp?

[RrogerD]

I've had the wall skimmed, but it's not drying out (see pics below). It's been about 3 weeks now. In fact it appears to be getting worse.
Can't say I'd noticed any damp issues prior. No smell of damp in the building etc. The paint was a bit poor but wasn't falling off and the plaster was fine.
Any thoughts anyone?

 

[jacko555]

What's on the other side of the wall

 

[RrogerD]

What's on the other side of the wall

Good point! It's a party wall.
Immediately behind is the kitchen area of the adjoining property. They're in a state of upheaval with building works themselves. I've spoken to the chap but assures me that they don't have a leak. I'm beginning to think it may be something....

 

[^woody^]

Is it a cavity or solid wall?

Even that back wall below the window is still damp, which is odd. Are you ventilating the room constantly and/or heating it?

 

[CBW]

Rising damp will rise approx 1m. Is it me or is the floor damp? Is there any moisture on the cable for the sockets?

 

[RrogerD]

Is it a cavity or solid wall?

Even that back wall below the window is still damp, which is odd. Are you ventilating the room constantly and/or heating it?

Sorry forgot to say, the bit below the window was skimmed only a couple of days ago so still drying out.

As to the party wall, I suspect solid. They are 1800's properties although mine is a conversion in the 1980's from I understand it, a garage. The party walls either side are bonded and skimmed whilst the internal walls are studding / blockwork.

 

[RrogerD]

Rising damp will rise approx 1m. Is it me or is the floor damp? Is there any moisture on the cable for the sockets?

No the floor is dry. The bit to the right, in the corner of the second photo I think is where the plasterer has knocked over his cup. He was there today finishing of the reveals in the window and other works.

No moisture on the cable and sockets. I'll double-check again tomorrow though

 

[CBW]

Might be worth checking that small roof section as well.

 

[tony1851]

Salts?

 

[RrogerD]

Salts?

What do you mean? I've stuck a damp meter into it and unfortunately it shoots right off the scale.
Do you mean that it is absorbing moisture from the atmosphere?

 

[tony1851]

What do you mean? I've stuck a damp meter into it and unfortunately it shoots right off the scale.
Do you mean that it is absorbing moisture from the atmosphere?

Google 'hygroscopic salts'.
These can be drawn up into the wall in the absence of a dpc (they can be from the ground beneath or the bricks themselves). They can form just below the wall surface, and attract moisture to them (eg from cooking/washing etc) and appear as a damp patch.
Not saying it is that, but worth considering.
When most older houses are renovated, usual practice is to plaster with a first coat of salt-resistant plaster.

 

[RrogerD]

Google 'hygroscopic salts'.
These can be drawn up into the wall in the absence of a dpc (they can be from the ground beneath or the bricks themselves). They can form just below the wall surface, and attract moisture to them (eg from cooking/washing etc) and appear as a damp patch.
Not saying it is that, but worth considering.
When most older houses are renovated, usual practice is to plaster with a first coat of salt-resistant plaster.

Interesting. I'll look into that one. Thanks

 

[tell80]

Looks like its rising damp on both walls. why dont you remove the both skirtings and look for a membrane coming from below the concrete floor that should show behind the skirting boards? If you have rising damp on a solid party wallthen the neighbour must have it on his side of the party wall too.
Theres a better way of doing things but you would firsthave to knock off the plaster back to bricks.
Is that a dormer above left?

 

[JohnD]

you have a substantial damp patch, all along one party wall, seemingly in one room only, and starting at floor level.

It looks to me like a plumbing leak.

The damp patch is hill-shaped so the source is probably near the top of the hill.

Why would "rising damp" be on only one wall?

I note that the neighbour's kitchen is on the other side of the wall.

 

[mrrusty]

I think Tony may be right. I've seen it before in old walls. The bricks/plaster are salt loaded from old combustion products reactions from when we burnt more coal. Wet trades draw the salts which are hygroscopic from the existing wall, and also the lower wall is the coldest part so most likely to have a condensation risk.

If you cannot find a leak anywhere, this is a possibility. I have had some success around a hearth by painting with damp-seal paint prior to wall finish, not to keep the damp in the wall, but to keep the humidity in the room away from the salts. As to "rising damp", we can agree to disagree about that...