Although mold can be easily cleaned on hard surfaces, once it has attached itself to a porous surface, it grows “roots”. It can slowly burrow into wood or drywall, so even though you may have visibly removed it from a surface, the mold is still there and will reappear shortly after because it wasn’t eliminated completely. Mold can even grow beneath wallpaper and paint, flooring, wood, fabric, paper or insulation; if it’s damp or wet it is the perfect environment for mold to grow!