Factors involved in the colonisation of building facades by algae and cyanobacteria in France

Algae and cyanobacteria are colonisers of building facades. A multivariate analysis of data gathered during a sampling campaign around France proved that precipitation, hygrometry, thermal amplitude, distance from the sea and proximity to vegetation were environmental parameters influencing this colonisation. Other influencing factors could be attributed to the nature of the facade coating, mineral substrata being more frequently colonised, and to the architecture, favouring in some cases the formation of damp conditions and thus the colonisation of the building envelope.