A pile foundation is a foundation method in which long piles are driven or drilled into the ground until they reach a deep, load-bearing soil layer. This method is used when the upper soil layers are too soft to support a building — think of peat and clay areas in the western Netherlands.
How does it work?
The piles act as vertical columns that transfer the weight of the building through the soft upper layers to a firm sand layer deep in the ground. On top of the piles, a concrete beam or slab is poured on which the walls are built.
The difference with a strip foundation is fundamental:
- Strip foundation — Rests directly on a shallow load-bearing layer
- Pile foundation — Goes through soft layers to reach a deep load-bearing layer
When is a pile foundation needed?
| Situation | Pile foundation needed? |
|---|---|
| Sandy soil (east/south NL) | No — strip foundation is sufficient |
| Clay on sand | Usually not — depends on layer thickness |
| Thick peat layer (west NL) | Yes |
| Reclaimed land | Yes |
| Heavy structure (multiple storeys) | Often yes |
Types of piles
Driven piles (precast concrete)
The traditional method: precast concrete piles driven into the ground with a pile driver. Reliable, but causes vibrations and noise.
Screw piles
Steel piles with a screw blade that are turned into the ground. Fewer vibrations, suitable for construction near existing buildings.
Bored piles
A hole is drilled and filled on site with concrete and reinforcement. Vibration-free, but more expensive.
Timber piles
The oldest method. Still present under many historic buildings in Amsterdam and other cities. No longer used for new construction.
Pile foundations for DIY projects
For a garden shed, outbuilding, or pergola, a pile foundation is usually not needed and also not a DIY job. The alternatives:
- Pier foundation — Individual concrete piers at strategic points. Suitable for lightweight structures.
- Ground screws — A DIY-friendly alternative: steel screws that you turn into the ground with a machine or by hand. Does not reach the depth of driven piles, but is sufficient for lightweight structures on moderately soft ground.
> Important: If you want to place a heavier structure on soft ground (brick garage, large shed), always have a soil investigation report done. This tells you at what depth the load-bearing layer is and whether you need piles.
Cost indication
| Type | Cost per pile (indication) |
|---|---|
| Driven pile (precast concrete) | EUR 40-80 per linear metre |
| Screw pile | EUR 150-300 per pile |
| Bored pile | EUR 80-150 per linear metre |
| Ground screw (DIY) | EUR 30-60 per screw |
Including pile driver and labour, a pile foundation for a garage quickly costs EUR 3,000-8,000, depending on the number of piles and the depth.
Related terms
- Strip foundation
- Pier
- Strip footing
- Concrete slab (floor slab)
- Reinforcement