The Green Chemistry Project (CERC) involves a significant transformation of the Pâtes et Papiers (1927) and Otto Maas (1964) Pavilions at McGill University, as well as the replacement of their electromechanical systems, to create state-of-the-art laboratories and offices for green chemistry researcher and their team. A significant project component was rehabilitating the building envelope and adding a mechanical extension to the Mills Wing of the Pâtes et Papiers Pavilion, situated in a tight inner courtyard of the McGill campus. The complexity lay in the restricted layout of the site and the need to maintain circulation during the construction works. A phased plan was developed to ensure the university pavilions remained operational throughout the construction. Comprehensive asbestos removal work was required. The project aims to obtain LEED Silver certification.