Helical underpinning uses helical piles, steel shafts with screw-like bearing plates, twisted into the ground beneath an existing foundation to transfer its load to deeper, more reliable soil, stabilizing or lifting settled sections.
It has become one of the most widely used underpinning methods for residential foundation repair, largely because of how quickly and cleanly it can be installed compared to older techniques.
What Does Helical Underpinning Involve?
- Helical piles twisted into the ground with hydraulic equipment
- Brackets connecting the piles to the existing foundation
- Torque monitoring to confirm adequate bearing capacity
- Potential lifting of settled sections back toward original position
Why Is Helical Underpinning Important?
Because helical piles can be installed quickly with relatively compact equipment and minimal vibration, this method has become a go-to solution for homeowners dealing with foundation settlement, particularly on expansive clay soils where the underlying cause is unlikely to disappear on its own. The ability to measure installation torque and correlate it directly to load capacity also gives engineers a reliable way to confirm the repair will actually perform as intended.
In many cases, helical piles can also be used to carefully lift a settled section of foundation back closer to its original elevation, closing gaps and cracks that developed as the structure sank, though how much lift is safe to attempt depends on the specific damage already present. Manufacturers generally provide detailed engineering data correlating installation torque with load capacity, giving both the installer and any reviewing engineer a documented basis for confirming the repair meets its design requirements. This documentation also proves valuable if the property is sold, giving future owners confidence in the repair’s engineering basis.
Helical Underpinning vs. Mini-Pile Underpinning
Helical underpinning uses piles screwed into the ground with measurable torque. Mini-pile underpinning uses drilled and grouted piles instead, generally chosen when soil conditions or required capacity favor a drilled approach over a mechanically driven one.