Piled Foundation Solution for High Heave Clay Soil in Surrey
Properties built on highly shrinkable clay are at significant risk of movement, especially following tree removal. Preformed Substructures Ltd designed a robust heave-resistant foundation system for a two-storey extension in Surrey.
Project Summary
Geotechnical investigations identified a deep zone of highly plastic clay with high heave potential. A traditional trench fill foundation would have to have been of a significant depth to create a concrete footing with a mass large enough to resist the forces exerted by the heaving soil. These deep footings would have been expensive, messy and take a considerable amount of time and resource compared to our pile supported ground beam solution.
Step-by-Step Project Delivery
- 1
Ground Investigation Review
Soil samples confirmed a deep active clay zone prone to swelling and shrinkage.
- 2
Foundation Selection
A piled foundation with heave protection was selected to anchor the structure into the firm soil below the active heave zone.
- 3
Heave Protection Design
We incorporated:
- Compressible heave boards
- Void formers below beams
- Fully suspended floor slab
to prevent upward soil pressure on the structure.
- 4
Pile Installation
Using our excavator mounted piling equipment the piles were installed to reach stable strata below the clay’s movement zone.
- 5
Ground Beam Construction
Reinforced concrete beams were cast above heave protection materials.
- 6
Certification & Handover
Full piling logs and engineering approval were issued.
Results
The client now has a stable, long-lasting foundation system designed specifically for clay heave conditions in Surrey and the South East.
If you are interested in exploring our helical pile foundation solutions, please get in touch with Preformed Substructures today.