Damp around socket

Removing the emulsion etc layers and painting the affected area with limewash sometimes works. The limewash is porous and permits evaporation, whereas emulsion tends to trap the damp.

Yes I did exactly the same many years ago when rewiring the kitchen of our first house... ended up with all the plastered-over cable chases coming back to haunt me the following winter!

Copious amounts of stain-block paint seemed to work pretty well for a couple of years at least - can't tell you how long for as we moved. Surveyor never apparently picked up anything untoward, anyway!

David

Question? With what material did you bed in the socket and make good around it - plaster-wise? If (not saying it was!) by any chance you used a gypsum plaster that would be your explanation. Cure? take it out again, improve depth a few mm, paint Febbond SBR and while still wet and tacky put on a thin slurry of, say, 1:1 cement fine sand with Sika No 1 and Febbond in it allow to set and put in patress. Use same mix on any surrounding missing plaster. Only put finish plaster on the out mm or less! Chris PS the reason that the wall behind may still have been wet it that it takes many years for it to dry out and if the mortar is still hygroscopic it will never dry out BUT the purpose of the DPC is to stop more salts from being deposited and to prevent more water rising. So you have two possible sources of water in the rising damp of the wall a) actual water rising that HAS been stopped b) cyclical water from the atmosphere going to and from mortar that is contaminated which will never dry out Most people don't use silicone these days - there are better products and some of them even work!

Of course it will not match your decor, and will flake off as well.

Inject the wall behind or point it with a sealer that soaks in..

and use expanding foam around any cables coming in from way back.

Matt emulsion is very porous and permits evaporation. However, prolonged exposure to excessive moisture will eventually soften the paint and it will come away from the plaster particularly if the first coat wasn't well thinned in order to bind with the plaster surface.

Some of the kitchen/bathroom paints are not porous though, and deliberately so to prevent condensation penetrating and to make them wipe clean without staining.

About £25 for 5 litres last time I looked

and while

But to a lesser extent than limewash

Lime is better to some degree on that point, as it doesnt rely on a water soluble glue.

NT