Adapting Hydrophobizing Impregnation Agents to the Object

Abstract In general, old buildings consume substantially more energy than new ones. Many historical buildings have brick-, natural stone and lavishly decorated facades that limit installation of outer insulation hence this is done on the inner side during energetic refurbishment. As a result, heat hardly gets into these walls during winter. Therefore, when driving rain penetrates into the facade in winter months, moisture cannot properly dry out and consequently, such facades remain wet for a very long time cooling down extremely, which increases the potential for frost damages. A solution is to match the degree of water repellency of the existing building materials in the specific construction with its driving rain load as well as to the properties of the chosen interior insulation. This should be done under the premise of a minimum intervention, i.e., do as much as necessary but as little as possible. One example is thoroughly discussed to illustrate this approach.