The damp that appears in properties tends to be quite severe as it has taken quite some time to break through and cause this internally, with this said it will not disappear overnight. Every property in the UK with concrete guttering will have experienced different levels of damp internally.
Homeowners may catch the damp in the early stages and have the concrete guttering replaced others will have experienced it for a while and tried temporary measures, but the damp will come through more aggressively.
These two very different scenarios will also vary the amount of time it will take for the damp to disappear. The stains will be left so redecorating is inevitable however if you attempt to decorate too early then the chances of the damp reappearing even only slightly is still there.
We average at Adeft allowing around 2-3 months for the walls to dry out before redecorating, this will stop any waste of money redecorating too early.