Establishing In-Place Structural Drying Goals: A Scientific Approach

Structural drying is essential to water mitigation. When a water release or intrusion occurs, a prompt effort is expected to remove wet contents and unsalvageable building materials followed by an accelerated drying to reduce moisture content to an appropriate level. However, agreement between responsible parties is often lacking as to what is appropriate, and drying efforts beyond this goal are unnecessary and wasteful. Prolonged drying efforts by contractors often clash with those bearing the financial responsibility despite the implied assurance that the extended desiccation promotes a higher probability of restoration success. This paper explores a rational and justifiable basis to develop a cost effective and efficient drying protocol. The scholarly works published by the USDA Forestry Products Laboratory and other peer-reviewed publications were reviewed to develop a rationale for establishing appropriate in-place structural drying standards, applying the concepts of equilibrium moisture content (EMC) and other critical moisture thresholds in the built environment. Guidelines from industry technical standards were also presented to calculate appropriate equipment requirements and methods to maximize dry-out efficiency. Critical moisture levels and their reasoning were discussed, as were some of the consequences associated with certain drying practices. The principles and practices of moisture measurement in building materials were described, and potential for inaccuracies was presented.