Underpinning in Newcastle

Underpinning adds support under an existing footing. In NSW it is licensed building work: the Home Building Regulation names "underpinning or piering" as a trade category, and the NSW Government says a contractor licence is needed once labour and materials pass A$5,000.

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What underpinning in Newcastle actually involves

The NSW Government defines underpinning as building a new support structure under a wall, column or footings without removing the superstructure, to stop a collapse from excessive settlement or another failure, to let the loads on a building increase, or to let the ground level inside or outside it be lowered. CSIRO's footing guide says remediation of footings and foundations is generally the realm of a specialist consultant, and that where the cause is a failed water service, roof plumbing, sewer or stormwater system, the remedy is to repair that.

A single-storey brick house with a gabled front and a tiled roof on a suburban street, a stair-step crack running down the front wall beside the window, neighbouring houses and a footpath in front — underpinning, Newcastle. Illustrative example.

Digging beside a footing

CSIRO says excavation around footings must be properly engineered. Guidance from the Welsh Government, which is outside NSW, describes the usual method as digging short sections under the footing one at a time, warns that voids can remain between new concrete and the old footing, and says the first step is generally a trial hole beside the footings, assessed by an engineer or surveyor. So ask a provider what they will dig first, and who will read what it shows.

Part of the City of Newcastle is inside a declared Mine Subsidence District. Subsidence Advisory NSW, the regulator, says you must obtain its approval to build or subdivide within a district, and its policy says any erection or alteration of an improvement needs its approval. None of the pages we read names underpinning as work that does or does not need it, so ask the regulator, the council or a certifier about the job. The council's plan asks for plans stamped by the regulator to go in with a development application in a district, and council's acid sulfate soils page counts the construction of footings among works that can need a management plan on mapped land. The mine subsidence page sets out each source.