Screw Pile Underpinning to Stabilise Subsidence in North London
Subsidence is a common issue in London due to clay soils and ageing drainage systems. Preformed Substructures Ltd were appointed to stabilise a subsiding external wall from within the basement using helical screw pile underpinning.
Project Summary
Crack monitoring revealed ongoing settlement. The structural engineer recommended screw piles due to limited access and the need for minimal vibration.
Step-by-Step Project Delivery
- 1
Structural Assessment
We reviewed monitoring logs and excavation requirements with the engineer.
- 2
Selection of Screw Pile Underpinning
Helical piles were chosen because they:
- Require minimal excavation
- Provide immediate load-bearing capacity
- Cause no vibration to neighbouring properties
- 3
Access Preparation
Small pits were opened to expose the foundation while maintaining support.
- 4
Screw Pile Installation
Piles were driven to depth using hand held pile installation equipment. Torque readings confirmed load capacity.
- 5
Foundation Connection
Underpinning brackets connected the piles to the existing foundation, then hydraulically jacked into place transferring the building load safely.
- 6
Final Reinstatement
All access pits were backfilled, and surfaces reinstated.
Results
The building was stabilised quickly and efficiently with minimal disruption, preventing further subsidence.
Need help with screw piles in London or the South East of England? Get in touch with Preformed Substructures today for more info.