Causes of Foundation Failure in Buildings
Foundation failure in a building can have various causes, but one of the most common ones is the shifting of the soil beneath the foundation footings. The soil movement can be due to shrinkage or expansion of the soil, which can result in settlement or heave, respectively. In dry conditions, the soil loses moisture, causing shrinkage, while high moisture levels cause the soil to swell. In either case, the movement of the soil can lead to visible cracks in different parts of the building, such as the foundation walls, exterior brick walls, or interior sheetrock or plaster walls. This type of movement is technically referred to as differential settlement.
Different soil types can lead to differential settlement and low bearing capacity, including subsurface peat, sand, and silt. Additionally, poor drainage from yard run-off and gutter downspouts discharging at the base of the foundation can cause excess moisture around the foundation, leading to over-saturated soils and loss of bearing pressure. The process of transpiration, where trees and large plantings absorb water from the soils around the home, can also contribute to soil shrinkage and settlement, particularly in areas with expansive soils. Plumbing leaks can cause foundation failure if the foundation is inundated with water from the home’s pipes, while poor outside drainage can also contribute. Although poor construction can sometimes cause foundation settlement, this is a relatively rare cause.