Screw Piles in Melbourne

What screw piles in Melbourne actually involves

An Australian Geomechanics paper describes the steel screw pile it studies as a shaft of circular hollow section steel with a plate welded to its end, resisting load by shaft friction and end bearing. A paper from the 10th Australia New Zealand Conference on Geomechanics says they are installed by rotation from a drive motor on a hydraulic excavator, and that their geotechnical strength depends critically on the plate's bending strength. So the first question is what governs this pile's capacity: the plate, or the ground.

More questions to ask

Second, what set the founding levels? The same conference paper says a site investigation, preferably using cone penetration testing, should form the basis for founding levels on a steel screw pile contract. Third, who designed it? CSIRO calls remediation of footings and foundations generally the realm of a specialist consultant, and the paper notes steel screw piles have their widest use in low to medium rise buildings, not as a stated fit for any particular house.

Victorian law adds one more. Where a major domestic building contract will alter the footings or may adversely affect them, the builder must obtain foundations data before the contract is signed — ask what that data showed and what the pile design rests on. None of the papers we found establishes how a screw pile connects to an existing footing, how deep it goes under a house, whether it suits a given soil, or what it costs or is warranted for.

Screw Piles in Melbourne — common questions

Are screw piles better than other underpinning?

We found no independent source that compares them. Published pile prices come from businesses that sell them, so the pricing page shows none.

What sets a screw pile's founding level?

A conference paper on steel screw piles says a site investigation, preferably using cone penetration testing, should form the basis for founding levels. Ask what investigation your provider has done, and what it found.

What are screw piles used for?

The conference paper names underpinning as one of many applications, with its greatest impact on low to medium rise buildings, but gives no method for underpinning a house.