Field Study on Hydrophobised Internally Insulated Masonry Walls

Abstract

This paper presents a field study on the hygrothermal performance of hydrophobised masonry walls, provided with vapour tight or capillary active interior insulation. As a reference, also nonhydrophobised and non-insulated walls are analysed. To study the hygric performance, apart from traditional relative humidity sensors, in-house made moisture pins are embedded in the walls and are shown to yield valuable information in the high moisture range. Attention is given to the hygric performance of the wooden beam heads, the impact of wind-driven rain on the moisture conditions in the masonry wall, as well as to the impregnation depth of the water repellent agent. For the latter, the field study is supplemented with X-ray and liquid droplet measurements on a small semi-duplicate test wall. During the hydrophobisation process, an increased moisture level was induced. A drying period was needed to again reduce this level. After this period, a hydrophobic treatment showed a positive impact on the wall's hygric performance. The non-hydrophobised wall with a vapour tight interior insulation system showed the highest moisture level, especially deeper in the wall and thus where the wooden beam ends are located.