Condensation is the most misunderstood humidity problem in modern Maltese buildings. Unlike rising damp, which comes from the ground, condensation is generated inside the building — by occupants breathing, cooking, showering and drying clothes. In traditional Maltese buildings with thick limestone walls and natural ventilation, this moisture could escape through the walls and open windows. But modern concrete apartments are airtight, and when finished with impermeable paints and renders, the moisture has nowhere to go. It accumulates on the coldest surfaces — typically north-facing walls, window reveals, and thermal bridges where concrete columns meet external walls. When surface temperature drops below the dew point, water vapour condenses into liquid water. This creates the perfect environment for black mould (Stachybotrys chartarum and Aspergillus species), which produces mycotoxins linked to respiratory problems, allergies and chronic fatigue. The solution is not simply cleaning the mould — it will return within weeks. The only lasting fix is a combination of proper ventilation and breathable wall finishes that allow moisture to pass through harmlessly.