Underpinning is a process by which the existing foundation of a building is re-supported and reinforced to distribute the load over a larger surface area or back onto competent ground. This process becomes necessary when the existing foundation can no longer bear the weight of the house.

Why do existing foundations fail to bear the load of the building or structure?

Here are some reasons that affect the load-bearing capability of a home’s foundation:

1.Subsidence or erosion at site

2.Broken services causing water saturation

3.Poorly designed foundation

4.Presence of large trees on site and/or dry soil in times of drought

How can underpinning save your home?

The rationale behind house underpinning is to provide greater support to the foundation so that it stands on stiff, stable, and stronger soil, which is unlikely to move. There are three ways of undertaking underpinning in Sydney.  

Concrete footings: Newer footings at an increased depth are constructed below the existing foundation to offer stability and restrict ensuing movement

Screw-pile: Existing concrete footings are used alongside steel piers to offer the existing foundation a better and more stable soil to stand on. The building can be jacked up to its earlier position, closing cracks and gaps, if there are any. This method is supposed to offer a permanent solution to restrict ground movements around the house in the future.

Polyurethane resin injection: A much newer method than its predecessors, this involves injecting the soil that surrounds the weak foundation with polyurethane resin. It fills up the void below the footings due to its expansive properties and subsequently dynamically compresses the soil increasing the ground’s bearing capacity.  

If it seems that your house is sinking or leaning, if there are gaps around doors and windows, or walls cracking, it may be a sign that your house needs underpinning. Our team provides underpinning services in Brisbane, Sydney, Canberra & Melbourne. If your home is experiencing any of these symptoms, then call our Raise & Relevel Specialists today.