You’ve noticed that “musty” smell, and you are wondering - Is there mould in my home? And what has caused it? Mould is a visual sign of excess moisture in your home and it grows due to various reasons. The most common cause of mould growth in your home is due to excess condensation, and many people do not realise just how much condensation can be created by normal everyday life in the home. Condensation is quite ok in your average house, but it should dry up fairly quickly or if it continues to lay stagnant mould could start to grow.