Principles 

Water is present during the construction, service life and deconstruction of all buildings. This water may be needed by the building in the form of an additive to a construction material, used by occupants, or the result of weather elements. Moisture problems in buildings stem from leakage in the building envelope, plumbing leaks, excess water and water vapor in the air, freezing of water in materials, the migration of water vapor through materials and systems leading to condensation and wetting of the materials. While all building materials absorb water, each absorbs at different rates and has different capacities. In addition, the absorption of water will affect the physical properties of the materials.