This paper explores the barriers facing Knowledge Management (KM) practices in the South African construction sector, with particular focus on the extension of KM beyond the boundaries of an organisation. Despite the sector's recognition as a key driver for socio-economic sustainability, problems have arisen in extending KM practices beyond organisational boundaries. Using an online questionnaire survey distributed among South African construction professionals, this research identifies barriers such as lack of KM training and managerial support, insufficient time allocated for KM activities, and the complexities of the construction sector, a lack of training, inadequate time for KM activities, resistance to knowledge sharing and the complexity of a multi-organisational and highly diverse construction sector. Contrary to expectations, aspects such as language diversity and job security concerns did not pose significant challenges. The study also reveals a positive attitude towards KM and a willingness to extend KM strategies. Recommendations include investing in KM training, fostering long-term partnerships for knowledge sharing, and ensuring the continuity of project teams. Potential areas for future research are not limited to exploring KM strategies utilised by South African organisations and examining the challenges small and medium enterprises face.