Cracking in buildings is common in NSW and particularly in the Strathfield Council area. Most of Strathfield Council area is built upon reactive clay soil. During periods of drought, clay soil ‘shrinks’ when it dries out and buildings supported by these soil types tend to settle unevenly when the shrinkage occurs, leading to cracking in brickwork particularly around window and door openings. However, after periods of rain, dry clay soil can ‘swell’. Swelling of soil can also cause cracking and lifting or heaving of buildings. The ‘shrink’ and ‘swell’ cycles can also cause cracks to open and close without significant extra damage.
Cracking itself does not necessarily indicate major structural problems or safety or stability issues, unless walls tilt to a substantial degree or there is a danger of falling material or dislodgement of lintels, floor or roof structures. It is usually not possible to completely eliminate cracking of existing buildings on reactive clay soils, however it is beneficial to regularly repair any cracking to reduce further damage and to allow buildings to remain habitable and serviceable.
The NSW Heritage Branch has produced a series of technical advices, which provide guidance on managing movement and damage from cracking. Please follow links for advices on Cracking in buildings due to shrink/swell in clay soils.
Owners of statutory heritage listed buildings may be eligible for financial assistance for repair work from Council’s Local Heritage Assistance Fund.