Hygrothermal Monitoring of Timber-Frame Replacement Infill Panels 

This project looked at the risk of interstitial condensation and increased moisture content within replacement infill panels for timber-framed buildings, as well as the potential impact on the surrounding historic fabric.

The project monitored physical mock-up panels, due to the limitations of computational simulation and real-world monitoring. These panels formed the northern wall of a small test cell with an internal climate environmentally controlled during the heating season. It featured four different replacement infill panels within reclaimed oak frames. The infill materials included in this study were wattle-and-daub, a composite of wood fibre and wood wool detail, expanded cork board, and hempcrete.

Hygrothermal conditions within the panels were monitored using embedded sensors, providing real-time data on moisture levels and temperature variations. Simultaneously, hygrothermal simulations were conducted using actual internal and external climate data to compare with the physical measurements, allowing for an evaluation of the reliability of numerical modelling for this type of construction. In addition, the thermal conductivity of the infill panels was measured to better understand their performance in real-world conditions.

After the completion of 2 years of monitoring, follow on funding was obtained and monitoring continues. The results have been shared in academic and industry publications, and it is hoped that these will inform revisions to best practice guidance.

• University of Bath
• UK Hempcrete
• Ty Mawr Lime Ltd
• Royston Davies Conservation Builders