Structural drying is a simple concept: Remove excess moisture from wet materials that make up the structure until it reaches a reasonable approximation of a dry standard or goal. Therefore, drying wet buildings involves removing trapped moisture in building materials (e.g. drywall, dimensional lumber, concrete, etc.).
The challenges take place in deciding what the end game, or drying goal, should be so that the affected structural material dries within an acceptable range, in a reasonable time frame and takes into account budgetary restrictions.