Moisture Ingress in Building Envelope Materials: (II) Transport Mechanisms and Practical Mitigation Approaches

The primary goal of this review is to explore both the fundamental dynamics of moisture ingress and practical strategies for its mitigation. Moisture ingress remains a critical issue due to its impact on the structural integrity of buildings and the health and safety of occupants. This work adopts a systematic approach, focusing on key mechanisms of water transport—capillary action, vapour diffusion, and condensation—and how different parameters influence the process of moisture transport. Moisture ingress, whether through direct leakage, capillary action, air infiltration, or vapour diffusion, poses significant risks to the premature degradation of building envelope materials. In this study, emphasis has been placed on describing the methods for controlling liquid water movement, preventing condensation, and using moisture-resistant materials. Additionally in this study, the advanced design and hygrothermal performance simulation tools are examined; the use of such tools is considered essential for predicting and managing moisture-related issues in building envelopes. Finally, the significance of complying with moisture control standards and guidelines is highlighted, ensuring a comprehensive framework for effective moisture management in building design and maintenance. Beyond this review, key knowledge gaps in moisture control strategies have been identified, particularly in respect to material performance, the accuracy of predictive modeling, and the standardization of mitigation techniques. Addressing these gaps is essential for advancing building design, maintenance practices, and regulatory frameworks that together combine to enhance moisture resilience.