Since 2015, ICBBM conference series have been held biennially at venues in Clermont-Ferrand 2015/2017 (France) and Belfast, UK 2019, the 4^th ICBBM2019 will be held from the 16^th to 18^th June 2021 (Barcelona, Spain). This conference has become established as a leading forum for Scientists across a broad range of disciplines to share their experiences on the application of Bio-Based-Building Materials (3BM).  The last conference attracted more than 260 participants from 40 countries worldwide, and 150 peer-reviewed papers were delivered.