Zinsser watertite for penetrating damp

[enzo808]

We've had some plastering and general renovation done at our house but noticed the plaster under the bay window of living room doesn't seem to be drying. The plastering was done almost 2 months ago in mid/late Jan.

Please find attached picture, as you'll notice there is some salt efflorescence on the surface.

Not sure if zinsser bin or watertite would do the trick before applying emulsion paint?
Have asked some damp experts to assess but in meantime thought I'd check online for people's opinion and experience. The pointing on the external stone wall seems intact so not sure if it's the window.

Thanks in advance

 

[Wayners]

Should it have been lime plaster?

That's not right having damp like that. Don't think it's condensation.

Put summer fan on to move air about may help but something is wrong there

No. Nothing will cover that. Don't apply anything