Wall plastered over after a roof leak, leak has been fixed but watermarks still in ceiling

Same should have been done to the ceiling, it could just be existing water soaking through while drying out, it could be a leak without looking it's really impossible to say, what it is, what should never have been done is covered over before being allowed to dry properly. Good luck Alex

Water marks on a recently plastered ceiling could indicate that there is still a leak coming through. However, it's also possible that the water stains were caused by the previous leak and are simply showing through the new plaster. To determine the cause of the water marks, it's important to inspect the area carefully. If the leak has been completely fixed and there is no evidence of water coming through, then the water marks may be cosmetic and can be painted over with a stain-blocking primer and a coat of paint. However, if there is any doubt about whether the leak has been fully repaired, it's important to investigate further before proceeding with any decorating work. If there is any sign of water or moisture on the ceiling, it's important to identify the source of the leak and address it promptly. This may involve further repairs to the roof or other areas of the building to prevent any further water damage. before decorating, it's important to inspect the area carefully to determine the cause of the water marks. If the leak has been fully fixed, the water marks can be stained block and painted over. However, if there is any doubt about the leak, it's important to investigate further and address the source of the problem before proceeding with any decorating work.

If you still got water Mark's after having new ceiling I'd say you still got bit of leak

Hello,I always tell my customers to leave any interior work for at least 8 weeks,just to make sure there is no water ingress occurring in same area,a lot also depends on what kind of repair you've had done on flat roof,dependant on what materials are used will determine how good the repair was,repairs can last for years if done correctly,but if the roofer has just done a quick repair that's where your problem stems from,my advice find out what repair youve had done and take it from there,you say you had a new flat roof done,did the roofer do it correctly?find a decent company to take photos and report back to you,hope this helps best regards mike higher roofing specialist