Mortar is organic because it contains resins, which supplies nutrients to
mould spores. The spores become established and the affection grows.
The affection is furthered by dirt and damp that is bound to the surface pores and which gives even more nutrients to the mould.
Constantly recurring mould will be problem as long as the surface contains spores and traces of mould. Sterilization of the mould –which disinfects of the surface- results in that all affection is killed off within 24 hours and that recurring affections becomes impossible for a minimum of four years.