Review of rainwater infiltration rates in wall assemblies

Detailed knowledge on expected infiltration percentages through various exterior cladding surfaces is of importance when conducting hygrothermal simulations to evaluate the long-term performance of wall assemblies. Due to the stochastic nature of rainwater infiltration through wall assemblies, it is not possible to precisely predict the amount of rainwater that will infiltrate. However, laboratory and field tests may provide insight into the range of infiltration rates that can be expected for a given cladding and insight into the impact of deficiencies and the parameters affecting infiltration. Therefore, quantitative studies concerning infiltration rates, which were mostly laboratory studies, were reviewed. Based on the reviewed studies, the driving forces for infiltration were determined and the impact of the applied test method, pressure difference and water deposition rate on the infiltration rates was analysed. A methodology to obtain information on infiltration percentages without performing additional laboratory tests was proposed and a categorization of cladding materials was developed.

Automated summary

Detailed knowledge on expected infiltration percentages of various exterior cladding surfaces is crucial for evaluating the long-term performance of wall assemblies through hygrothermal simulations. Laboratory and field tests provide insights into the range of infiltration rates and the impact of deficiencies and parameters affecting infiltration. Quantitative studies, mostly laboratory-based, were reviewed to determine the driving forces for infiltration and analyze the influence of test methods, pressure difference, and water deposition rate on infiltration rates. A methodology to obtain infiltration percentages without additional laboratory tests was proposed, along with the categorization of cladding materials.