Hygrothermal performance of a masonry wall retrofitted with interior insulation

A 4-storey masonry building was retrofitted and converted to offices. The wall retrofit included the addition of insulation and vapour and air barriers on the inside of the brick wall. A section of the retrofitted wall was continuously monitored for over two years. This paper describes the monitoring program and discusses the hygrothermal performance of the retrofitted masonry wall. The retrofit had a negligible effect on the drying potential of the brick wall during the summer months but reduced the wall drying potential during the winter months. The cooling rate of the brick mean temperature, at temperatures below 0degreesC, increased to -3.4degreesC/hr as compared to -2.7degreesC/hr for the uninsulated wall case. The moisture level in the brick wall increased, which was partially due to the retrofit and partially due to a wetter weather during the monitoring period. As a result of increased moisture level in the brick, the RSI-value of the brick wall decreased from an average of 0.31 in the first winter following the retrofit to an average value of 0.18 in the second winter months. The brick wall may be at a higher risk of frost damage than before the retrofit.