This project involved the retrofit and reordering of the existing dwelling, along with the addition of a new extension. PHPP energy modelling was carried out to assess the building’s performance and inform a phased ‘Medium Term Retrofit Plan’. Strategy drawings were developed to address insulation, ventilation, airtightness, and moisture management, supported by detailed build-ups for walls, roof, and floors. Comprehensive technical design information was prepared to guide the contractor during construction and support Building Regulations approval. The retrofit plan provided a clear, long-term strategy for improving the building fabric and delivering enhanced energy performance over time.