This paper analyses the environmentally sustainable retrofit of the Grade I-listed buildings at New Court for Trinity College, Cambridge. The paper critically reviews existing heritage and environmental policies as these relate to practice. The project on which the paper is based has brought together architects, engineers, building physicists, building conditions surveyors, and industry experts. The role of building physics and design, the monitoring and modelling of existing and future fabric conditions and building character are defined as essential components of a strategy to resolve the critical gaps between - and oppositions in - the policies addressing heritage and environmental sustainability. The case study unveils the complexity of the issues involved in such projects and the difficult, nuanced judgements to be made at every level of building physics, design, and policy interpretation. Indeed, there is a critical need for the appropriate allocation of resources (time, money, and intellectual rigour) by all parties involved in such projects to ensure that all decisions are made in a fully-informed and, hopefully, collaborative manner.
