Condensation on walls behind pictures

[littlejo67]

We have a bedroom with an outside wall. We had it sealed and re-plastered and painted recently. We have put 2 large pictures up on the outside wall part and the backs of the pictures have warped and there seems to be a micro climate going on behind them as water is condensing behind them and running down the wall. Also the plaster has cracked all around where the original picture rail used to be - I am thinking this is due to humidity.
Is there any way of hanging pictures away from the wall so air circulates? Or any other suggestions would be gratefully received.

How long ago was it re-plastered? Why was the work done - was it because of damp issues?

Have the gutters and pointing on the outside of the wall been checked?

It was re plastered over a year ago o ly just repainted. Yes because of damp issues.
Not sure when gutters were last checked, it's concrete block and was painted a few years ago looks sound but obviously it got to close to look in detail.

Hmm - I'm no expert, but I wonder what was done to 'seal' it. Unless whatever was the cause of the damp was fixed, it could have been like putting a sticking plaster on a broken leg.

The cracking round the picture rail repair is probably plaster shrinkage. Maybe it was done in one thick coat or on one day. Fine filler or easiplast, mixed in a very small quantity and squeezed hard into the cracks with a broad filling knife, pressing so hard that the smear on the surface is transparent and can be polished off with a rag, should fix it.

Condensation behind furniture and pictures is normal for condensation. Look for any sources of humidity such as wet washing, leaking radiators, faulty gutters or windowframes, and ventilate the room daily by opening the windows. I would expect to see condensation on the windows as well.

Thank you piglet

If you rule out external sources damp you need to look at internal sources as piglet says. Internal humidity is drawn to the cold spots in the house. If air cannot circulate in these areas (behind furniture and in cupboards) then mould and mildew will grow. If you can be conscious of ventilating your house sufficiently and extracting warm wet air effectively this will help massively.