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.

Abstract

New technical solutions are introduced at a fast pace in the Swedish construction industry, mainly driven by issues concerning costs and productivity. These new technical solutions can comprise new materials, new goods, new designs but also new processes. The record of accomplishment when introducing new technical solutions in the industry is not unproblematic and serial failures of different new technical solution have occurred. In an earlier interview study exploring introduction of new technical solutions in the Swedish construction industry, a common lack of thorough methods for evaluation of new solutions was identified. To address this issue, a case study was performed, exploring a method of evaluation with respect to building physics while implementing a cross laminated timber frame in a multifamily building. The case study uses a framework of assessment with focus on building physics. This paper presents the findings from the case study focusing on how evaluation of a new technical solution with respect to building physics is performed, together with an evaluation of the method, using the experiences of the participants in the case study.