Influence of the disparities between lab and in-situ application on the penetration depth of a hydrophobic agent

Abstract

Abstract Over the last few years, the application of a hydrophobic agent on a masonry wall has become popular due to its ability to reduce the amount of rain water absorption without changing the facade’s appearance. While the hygric properties of such hydrophobised materials are often investigated, research towards its penetration depth into materials is limited. Additionally, most existing research involves small samples made in a lab rather than masonry walls. This paper therefore focuses on two key differences between lab application and application on an actual masonry wall and their influence on the penetration depth of a hydrophobic agent. As the hydrophobic agent is applied differently on an in-situ masonry wall than on laboratory samples, the method of hydrophobisation is investigated first. It is shown that the penetration depth varies significantly for different methods of hydrophobisation as well as within single samples. Secondly, the existing research often targets separate brick or mortar samples rather than full-scale masonry walls. Therefore, several experimental methods are used to quantify the penetration depth in a masonry wall. From these experiments, it is shown that the penetration depth is not only variable throughout this wall, but within separate bricks or mortar joints as well.