A damp patch on a wall is a symptom, and painting over it before the actual source of moisture is resolved is close to guaranteed to bring the stain straight back through the new paint. Fixing the cause has to come before any decorating conversation.
Identifying and resolving the underlying cause — a leak, a failed damp course, condensation, or something else entirely — is a job for the relevant trade or a qualified surveyor, not a decorator. We will flag suspected causes but do not present ourselves as the diagnosis.
Affected plaster needs to dry out fully, which can take considerably longer than it looks like it should from the surface. Salts left behind by the moisture often need neutralising or the affected area needs replastering before decoration, since paint alone will not stop salt staining reappearing.
Even on genuinely dry plaster, residual staining can bleed through several coats of ordinary emulsion. A dedicated stain-blocking primer stops that migration and gives the finish coats a clean, even base to sit on.
We would advise against it — it almost always reappears through the new paint within weeks, and it delays finding the real cause.
That confirmation needs to come from whoever diagnosed and treated it, or from monitoring the area over time before we decorate over it.
In most cases yes, provided the underlying moisture problem is genuinely resolved. It cannot compensate for an ongoing leak or damp source.
Confirm the damp source has been resolved and we will assess the plaster before recommending redecoration.
Damp-affected plaster can be decorated once the source is fixed and the wall has properly dried out, not before.
Speak to a Hampshire commercial decorating contractor that turns up, communicates clearly and delivers a finish that lasts.
