Improving the design and performance of envelope assemblies has become an essential component of strategies to mitigate the impact of flood events on buildings. This study is part of a broader effort to address how envelope assemblies respond to flood events and to propose assemblies that are more resilient to water damage. Specifically, we study two aspects of water uptake to ascertain the significance of adsorbed and residual water on the post-catastrophe drying measures. Hydrostatic pressure and interstice networks contribute to additional moisture load in assemblies post-flooding, affecting the drying process and increasing the risk of long-term damage such as mold growth and wood degradation. By properly incorporating these factors as boundary conditions, simulations can more accurately evaluate the performance of various assemblies under different flood scenarios.