Introduced in 2019, South Africa's carbon tax has imposed escalating financial penalties on corporations exceeding emission limits, costing up to six billion rand annually. This research scrutinis es Construction Project Managers' (CPMs) perceived competencies in green retrofitting against the benchmarks established by the Council for the Built Environment (CBE) and the South African Council for the Project and Construction Management Professions (SACPCMP). It develops and validates Cognitive Competency Theo ry (CCT), which posits that the effectiveness of CPMs in executing sustainable retrofitting practices is markedly influenced by the synergistic relationship between their cognitive perceptions —including self - efficacy, outcome expectations, and personal age ncy—and their professional competencies, encompassing technical, behavioural, and contextual skills. This research underlines the criticality of bridging the gap between policy and practice to achieve sustainable outcomes in construction projects, especially amidst the pressures of carbon taxation and environmental regulations. Employing qualitative methods, the study engages with thirteen experienced CPMs in green refurbishment, unveiling that while CPMs play a central role in mediating carbon tax demands and championing sustainable development, they frequently lack comprehensive understanding of their role in environmental protection and adherence to carbon tax regulations. The conclusion posits that although CPMs are vital in navigating the complexities o f green retrofitting, it is imperative to further explore the evolving role of CPMs in relation to regulatory pressures and industry standards. The CBE underscores the necessity for CPMs to possess competencies across various project development stages, ye t the industry has not yet standardi sed sustainability competencies as a mandatory requirement for CPMs in South Africa . Keywords: Carbon Tax , Cognitive Competency Theory (CCT) , Construction Project Management , Council for the Built Environment (CBE), Environmental Impact Assessment (EIA), Green Retrofitting, Lifecycle Assessment (LCA), Qualitative Methods, Regulatory Compliance, South African Council for the Project and Construction Management Professions (SACPCMP), Sustainability Competencies, Sustainable Development. PREPRINT – 16/03/2024 – VERSION 2 – CC BY -SA 4.0 DEED – SUBMITTED TO THE INTERNATIONAL JOURNAL OF SUSTAINABILITY POLICY AND PRACTICE WITH A WORD COUNT OF: 7,678 (JOURNAL ACCEPTANCE RATE – UNKNOWN % AT TIME OF SUBMISSION) – CURRENT PUBLICATION STATUS – PASSED EDITORIAL ACCE PTANCE - CURRENTLY UNDER PEER REVIEW Page 2 of 26 Front Matter and Word Count: Original Manuscript - Research Article ( 7,678 ), this submission does relate to a conference, or a special issue related to the Journal , and is the original work of the authors, this submitted version coincides with the Preprint , Version 2 . An early version of this work (Version 1) was first presented at The South African Council for the Project and Construction Management Professions international research conference and Masterclass , for which made it into one of 5 premier conference presentation slots , with Version 2 being accepted to the Twenty -first International Conference on Environmental, Cultural, Economic & Social Sustainability to be held in Miami USA on January 23 - 25, 2025 under the theme, “Sustainable Development for a Dynamic Planet: Lessons, Priorities and Solutions . Word count excludes title, author names, author affiliations, abstract keywords, abbreviations, table/figure captions, acknowledgments, front matter and