Croft Foot Retrofit
Location: Sandwith, Cumbria
Status: Concept Stage
Performance Standard: Low Energy Retrofit
Key Features: Air Source Heat Pump, solid stone walls, energy-efficient retrofit
Croft Foot presents an engaging retrofit challenge rooted in its rich history as part of a detached farmhouse dating back to circa 1790. The subdivision in the 1980s created two semi-detached dwellings, with a conservatory addition that benefits from a south-facing aspect ideal for passive solar gain.
Constructed with sandstone solid walls externally rendered in cement, the property currently suffers from damp and deteriorating plaster, indicating the need for comprehensive internal refurbishment.
The ground floor varies between a suspended timber floor in the main house and a solid floor in the conservatory; both have limited insulation. Previous minor interventions insulated loft hatches and draught-proofing have laid some groundwork but fall short of significant thermal improvements.
We were engaged to assess the feasibility of retrofitting the property and provide support throughout the construction process. The internal condition requires significant refurbishment, with noticeable areas of damp and failing plaster. The client’s primary objective is to improve thermal comfort while undertaking necessary internal repairs and redecoration.
Our approach focused on exploring both internal and external wall insulation options. The client is receptive to substantial interventions, which allows for deeper retrofit measures to enhance energy efficiency and comfort.
Key design considerations included:
Internal/External Wall Insulation: External wall insulation (EWI) is constrained by the need to preserve the stone detailing on the façade, while limited eaves overhang restrict the thickness of EWI feasible. Internal wall insulation (IWI) is limited by the small internal spaces and detailing, restricting how thick the insulation can be without impacting room proportions.
Plant Room Integration: We proposed a new utility space of 2–3m² to accommodate a plant room for the installation of an air source heat pump, which is essential for a low-carbon heating solution.
Conservatory and Thermal Envelope: The south-facing conservatory offers a valuable opportunity for solar gain. However, disconnecting it thermally from the main house and potentially removing it from the thermal envelope simplifies overall retrofit complexity and enhances energy performance.
Challenges include the conservatory’s current integration with the house, limited space for a dedicated plant room, and the requirement to retain historic external stonework which limits external treatments.
Overall, this project offers excellent potential for a deeper retrofit, balancing the client’s ambition for significant improvement with the preservation constraints of a traditional building. Our ongoing support ensures smooth progress from design through construction, optimising thermal comfort and building performance.
