What is a common sign of mold growth in a building?

Visible stains or discoloration on walls and ceilings are indeed a common sign of mold growth in a building. This occurs because as mold develops, it can produce pigments that lead to dark or strange-colored patches on surfaces. These discolored areas often appear in places with high humidity, such as bathrooms or kitchens, and can indicate not only the presence of mold but also the potential for ongoing water issues.

While other factors like unusual odors or dust accumulation can be associated with various issues in a building, they are not as specific or universally recognized indicators of mold as visible stains are. Overheated walls may suggest insulation or HVAC problems but do not directly point to mold presence. Therefore, noticing any visible discoloration should prompt further investigation for potential moisture problems and mold remediation.