CIOB Ireland has responded to the public consultation on proposed amendments to Part D (Materials and Workmanship) of the Building Regulations. Our submission advocates for a regulatory framework that supports Ireland’s transition to a circular, low-carbon built environment. Key recommendations include establishing clear verification pathways for reclaimed materials to reduce embodied carbon and defining proper materials at the system level for Modern Methods of Construction (MMC). Furthermore, we called for the professionalization of site management, linking the definition of 'workmanlike manner' to the oversight of chartered professionals to ensure high-quality, resilient construction and reduce the prevalence of latent defects.