Structural Defects of Foundations at Construction Stage

Problem Areas

Effect on foundation

Defects in structure

Insufficient depth of foundation (mostly in soft clayey soil)

Movement of foundation due to changes in water table seasonally, and movement due to trees and vegetation.

Cracks in walls at natural lines of structural weakness, i.e. windows, doors, junctions with extension and bays.

Insufficient width of foundation

Settlement of foundation occurs due to insufficient distribution of load.

Cracking of walls above ground level.

Soft-spots in sub-soil

Foundation settles due to insufficient support from sub-soil.

Cracking in walls above affected section of foundation.

Insufficient steps in strip foundation on sloping ground.

Building may slide or creep in case there is soil erosion.

Displacement movement of building or section of building. Cracking in walls.

Trees and large shrubs close to building (mostly in case of soft shrinkable clayey soil)

Water-content of soil changes with season, i.e. desiccation occurs in absence of moisture and heave occurs with excess moisture.

Cracking in walls in line of weakness in structure.

Clayey soil with high sulphate content.

Sulphate attack in concrete foundation and cement mortar below ground level.

Movement in walls above ground level and expansion and deterioration of cement mortar and concrete below ground level.

Inadequate support to foundation from land-fill.

Excessive settlement of foundation which continues for a long time.

Cracking in walls, complete collapse of buildings.

Foundation near to drains where drains are running below foundation and / or drains lacking concrete cover.

Foundation is inadequately supported.

Cracking in walls occur above ground level and walls move out of plumb due to lateral movement of foundation.