The iconic Robert Brown Building within the grounds of the Royal Botanic Gardens is amongst a cluster of heritage buildings and former home to the NSW Hebarium. Built in the 1970’s the building was functional in purpose, housing RBG’s collection of 1.4million plant specimens. Following the relocation of the National Herbarium an opportunity was presented to repurpose the building and transform the design and aesthetics to an inviting environment for the future. The building has become the new home of the Research Centre for Ecosystem Resilience (ReCer). The works comprised the remediation of contaminated materials, façade remedial works, services upgrades, access upgrades were required to building entry points together with internal refurbishment works comprising high end exhibition and event and laboratory spaces. Heritage aspects of the building were also required to be considered in completing the refurbishment. The works had to be completed while partial occupation of the building existed including the library space housing 200+ year old books and documents, communications hub for the entire Botanic Gardens precinct and specimen preserving refrigerated rooms. External access was also restricted being in the busy Art Gallery/ Botanic Gardens precinct which resulted in severe restrictions to the movement and size of construction plant and materials. The nature of the site and its significant collection of flora and fauna had to be considered in all aspects of the construction resulting in modified methodology for many activities. The sequencing of the work was critical to ensure stability of the existing structure as well as worker and public safety during the construction phase. The overall quality of the works were high and Renascent had effectively managed the constraints imposed by this constrained site.