The concrete's organic qualities come from the ingredients sand, stone,
water and cement. These nutrients enable the mould's spores to establish
themselves on the concrete.
Dirt in the concretes pores also contains nutrition and binds damp, which furthers faster affection.
The mould's spores create strong holds in the concretes surface and recur as long as there are any spores left in the surface pores. Sterilization of all spores and all affections and disinfection of the concretes surface is necessary –to prevent and to stop all recurring affections.