CFA piling (Continuous Flight Auger piling) is a deep foundation method where a hollow-stemmed auger drills to the required depth in one continuous operation, then concrete is pumped through the hollow stem as the auger is withdrawn — forming a sealed concrete pile without any open borehole at any stage. No casing is required and no vibration is produced. ASAP Piling operates the MAIT HR75 CFA rig and has been installing CFA piles across Melbourne and Victoria since 2001.
CFA piling has become the preferred deep foundation method for large commercial, multi-storey residential, and inner-city construction projects across Melbourne. High production rates, vibration-free installation, and compatibility with Melbourne's soft clay and high-groundwater sites make CFA the go-to specification for builders, engineers, and developers on substantial projects.
How CFA Piling Works
The process starts with positioning the rig. The hollow-stemmed auger rotates into the ground — cuttings travel up the auger flights to the surface as it goes. Drilling continues until the required depth is confirmed. At that point, the concrete pump starts. Concrete flows under pressure down the hollow stem and out at the auger tip. As concrete flows, the auger is withdrawn at a rate that matches the concrete delivery — ensuring the concrete always fills the void as the auger rises. The borehole is never open at any point.
Once the auger is fully out, a steel reinforcement cage is vibrated into the fresh concrete while it is still workable. The whole process from rig positioning to cage installation takes 15 to 30 minutes per pile for standard sizes.
When CFA Piling Is the Right Choice
Soft or Loose Soils
Where an open borehole would collapse before concrete placement is possible — common on Melbourne's coastal fringe, former estuarine sites, and loose sandy fill.
High Groundwater
Docklands, Port Melbourne, Williamstown, and bayside coastal suburbs where any open borehole floods immediately.
Vibration-Sensitive Environments
Inner-city sites adjacent to existing buildings, hospitals, and heritage structures where no vibration is permitted.
Large-Scale Projects
Where pile quantities are high and production speed matters — 15 to 40 linear metres per hour versus 5 to 15 for standard bored piling.
When CFA Piling Is NOT Appropriate
Hard Rock: CFA augers cannot penetrate competent rock. ASAP Piling switches to down-hole hammer equipment when rock is encountered, but the CFA operation itself cannot continue through rock.
Obstructed Ground: Buried masonry, old foundations, or large boulders can stop auger penetration.
Contaminated Ground: CFA brings contaminated cuttings to the surface — specialist handling and disposal is required before starting.
Small Projects: CFA equipment mobilisation costs are higher than for standard bored piling. It becomes cost-competitive at approximately 50 linear metres of pile or more.
CFA Piling and Melbourne's Ground Conditions
Melbourne's geology varies significantly and CFA performs differently across zones:
South-Eastern Suburbs
Deep clay soils prone to swelling and closing any open borehole. CFA handles this well — the continuous operation and concrete pressure prevent borehole closure.
Inner Melbourne, Docklands, Port Melbourne
Soft estuarine soils and high groundwater at or near the surface. Open boreholes flood immediately. CFA is the standard method here.
Inner Northern and Western Suburbs
Shallow rock is present across much of Essendon, Brunswick, Footscray, and the western suburbs. CFA suits the soil above the rock but cannot penetrate it.
Bayside and Coastal Suburbs
Variable sandy soils and high groundwater. CFA is preferred where borehole stability in loose coastal sands is a concern.
ASAP Piling provides project-specific CFA quotations. Call Nick on 0499 888 799 with your engineer's pile schedule and soil report.
Frequently Asked Questions
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