The minerals and the different sediments provide nutrients that promote spores
Stone therefore gives nutrition to growth in its natural state and is even exposed to different climates. It assembles lots of dirt –that binds damp- which gives the very small black mould spores nutrition.
The mould establishes strong holds in the smallest of pore and therefore the affection is a fact. Every pore on the stone surface, every mould spore and all old growth must be removed for the affections to stop.