Black mould, or Stachybotrys chartarum, grows where humidity is high and ventilation is poor. These conditions are typical in older and rental properties across Cardiff, Merthyr Tydfil and Caerphilly.​ Mould spores can trigger coughing, wheezing, allergies and asthma flare ups in adults and children. Over time, it also stains plaster, peels paint and weakens wall…

South Wales homes face a perfect storm of conditions that allow mould to thrive before winter fully arrives. As temperatures drop and the heating goes on, moisture builds up indoors faster than many properties can safely release it. Older terraces, stone cottages and solid‑wall homes often have weaker insulation and ventilation. As a result, cold…