Evaluating Incidental Thermal Performance Improvements of a Historic Timber-Framed Building in Central Hereford

Abstract

As we strive to decarbonise our historic built environment, a balance must be struck between technical, aesthetic, philosophical and economic concerns. Compromises must be made and opportunities seized. At the same time, evaluation allows us to assess decisions previously made and reflect on their outcomes. This paper presents the evaluation of the refurbishment of The Old Mayor’s Parlour, Church Street, Hereford, a historic timber-framed building now used as a gallery and exhibition space. The conservation work undertaken was not specifically envisioned as an energy retrofit, however the necessary replacement of failing concrete block infill, the legacy of a 1970s renovation, allowed improvements to be made to the thermal performance of the external envelope. Environmental monitoring and digital simulation have been used to assess the impact of these interventions. In situ U-value measurements show the success of the replacement infill panels and associated internal lining, although digital energy simulations suggest a limited improvement to the building’s overall energy efficiency. At the same time thermography suggests a potential threat of increased condensation risk to the uninsulated ornate 17th century plaster ceiling. The results of this paper show the risk of unintended consequences and the challenges faced by sustainable building conservation.