Separate the different moisture sources
Rain, ground moisture, a leaking pipe and condensation need different responses. Identify the source before choosing a repair. Painting over a mark without resolving its cause leaves the new finish exposed to the same conditions. Consider weather and how the home is used during inspection.
External junctions matter
Provide a planned route for water to leave the building. Coordinate roof drainage, terraces, window junctions and ground drainage. Pay attention to material transitions and fixings. Details that will become inaccessible should be clearly resolved before they are covered.
Coordinate insulation and ventilation
Cold surfaces can collect condensation. Coordinate insulation continuity and window details with heating and ventilation. Tighter windows reduce incidental air leakage, so plan how fresh air will enter. A conventional split air conditioner does not necessarily provide an outdoor-air supply.
Check before final finishes
Inspect junctions and check drainage and building services. Allow wet construction layers to dry as their system requires. Photographs of concealed work and clear operating instructions are more useful than promises that one material will solve everything.