A concerned homeowner wanted to know the early signs of mould growth. At the initial stages of growth, mould may not be visible to the unaided eye. However, prevailing indoor conditions are a good indicator of potential mould growth. If the building has excess moisture due to roof or pipe leaks, flooding or condensation one would expect visible mould growth to appear on the damp surfaces at some point.

Musty or earthy odour could suggest there was some hidden microbial growth behind and underneath surfaces, such as carpets, wallpaper, cabinets, and walls. Visible mould growth may appear hairy or as slimy coloured patches that increase in size as the mould grows. It is difficult to tell the type of mould growing on a surface on the basis of colour. It is erroneously thought that visible black mould growth is Stachybotrys. There are many other indoor moulds that appear black or grey. The best way to know the type of mould growing indoors is to send a sample to a reputable laboratory for testing. For details on how one can take and send a sample to a laboratory click Mould in Your House.