Background: A large increase in surface growth on building façades has stimulated ongoing research on identifying colonising organisms and their impact on colonised surfaces. Aims: This paper focuses on the characterisation of initial ecological succession on building surfaces. Methods: Diverse investigations were used in an interdisciplinary approach to study early colonisation on modern building surfaces. Results: More than 200 different taxa have been identified as part of the early succession so far. Most of the diversity is contributed by algae and cyanoprokaryota, followed by fungi. Remarkably, bryophytes and lichens also make up an important part of the rich biodiversity on building surfaces. Along with the identification of the microorganisms their ecological thresholds become apparent. Façade algae may be active in a range of relative humidities from 68% to 100% and fungi from ca. 73.3% upwards. The upper temperature limits lie at 57°C for active and may surpass 100°C for the dormant stage. The lowest temperature for physiological activity of façade organisms is ca. −15°C. Surface growth on masonry develops in seasonal cycles. Conclusions: This overview covers succession, management of growth on buildings and deliberate greening of vertical building surfaces. New approaches for surface greening technologies with algae and bryophytes are on the way. The current discussions relate to whether microbial surface colonisation on buildings should be controlled or enhanced as a functional part of man-made ecosystems. Keywords: Aerophytic algae; biodiversity; initial colonisation; masonry; mould fungi.