Best Methods for Foundation Repairs
04/08/2021The foundation of a building is the soil or rock on which it stands and, on which, or through which the footings are constructed. The footings of a building can consist of piled arrangements, piers, strip footings, slabs on ground or a combination of systems used to transfer the dead and live loads of a building to the foundations.
In Sydney, Sydney Sandstone in most cases, provides a good stable material on which to found a building. If the rock layer is found at shallow to moderate depths then raft slabs, piers or piles can be utilised to provide effective footings. Smaller buildings, or buildings where the rock depth is excessive often resort to footing designs in the soil layers. Performance of footings in soil layers can vary depending on the applied loading, drainage and other environmental factors.
Inner Sydney is blessed with sandstone relatively close to the surface, or, there exists a relatively shallow sandy clay over that sandstone. As we move westwards deeper clay layers are found which often give rise to expansive clay conditions whereby clay layers shrink or swell depending on moisture content. Historically Sydney summers have provided good rainfall resulting in little difference in the moisture content of clay layers during summer or winter but of late more frequent drought conditions have caused a resurgence in damage to buildings due to the effects of expansive clays as the seasonal moisture differentials increase.
As a remedial building company and foundation repair experts we see foundation failure resulting from a variety of causes including inadequate initial understanding of the ground conditions leading to inadequate design. The old adage that ‘a site investigation is paid for whether it occurs or not’ often rings true as rectification costs mount.
Other causes of foundation failure include, inadequate control of ground water or changed ground water conditions. It is largely true that if you can control the water on site then the site is under control. Flooding, gradual seepage or installation of close by deep basements re-routing groundwater flow paths as an example, can all have damaging effects on footings.
Whilst there are many causes of footing failures in buildings, in all cases, there is a need to properly understand, design and construct remedial works to ensure effective repairs are undertaken. This requires the services of structural engineers to design the works and contractors to undertake the works. Both parties must be experienced and skilled in works of this type to make the problems just go away…
Contact Structial today!