Water is an essential ingredient in concrete.
Over-watered concrete, however, is subject to segregation of the aggregate, excessive shrinkage cracking, corrosion of reinforcing bars, and decreased strength and durability. Concrete failure has cost implications for builders and building owners, and can also damage the reputation of concrete as a suitable foundation material for houses and small buildings. Structural failure can result from excessive shrinkage cracking although, more typically, the appearance of cracks creates anxiety for building owners and can lead to reduced property values. Cracks in the concrete can result in cracks in the dampproofing material, allowing moisture in contact with the wall to pass through, leaving bothersome puddles on the floor and leading to high indoor humidity and wetting of interior finishes. Molds and mildews that thrive in such environments can present serious health problems.