What causes mould to grow indoors?
Mould is found and in most if not all locations on Earth. The Mir Space Station was even plagued with mold growing between the glass in the windows. Indoor moulds are outdoor moulds surviving indoors. Moulds are able to survive from freezing to about 140°F. To be overly simplistic, mould growth requires the viable spore + moisture (60% or more humidity or equivalent water activity level) + food (cellulose) + stagnant air (to avoid being blown away). An indoor area does not “get mould” it has always had mould from the day it was constructed. If the conditions indoors are right, the pre-existing mould indoors will amplify.
