Exploring the variability of hygrothermal material properties in historic bricks in London

Abstract

In the UK, a large number of traditional buildings are made of solid brick walls. If appropriate retrofit measures are taken, these buildings can contribute to achieving the UK Government’s pledge to reduce greenhouse gas emissions. The vast majority of solid brick buildings in London are non-insulated. Adding internal wall insulation is one possible energy retrofit measure, however, the insulation layer can alter the moisture balance of the wall. Since the hygrothermal properties of the existing building materials can influence the moisture balance of the wall considerably, identifying the wall type and understanding its hygrothermal properties is extremely important in building retrofit. The objective of this study is to explore the variability of the hygrothermal properties of different bricks from one wall located in London. Several brick samples are selected from one case study wall in London. The hygrothermal properties of 21 historic bricks were measured, including the absorption coefficient, bulk density, drying coefficient, water content at capillary saturation to determine the variability. The experimental results show variability of some material properties, particularly the absorption coefficient. This can potentially have significant implications for solid wall retrofit and material property characterization.