A Dordrecht foundation is a historic Dutch foundation method, developed in Dordrecht, in which timber piles are topped with cross-beams (‘kespen’), a longitudinal beam and then a masonry foundation or wall. The system was widely used on soft peat and clay soils.
Build-up of a Dordrecht foundation
The foundation consists of several layers, from the bottom up:
- Timber piles — timber piles (often pine or fir) driven down into a load-bearing sand layer
- Kespen (cross-beams) — horizontal cross-beams laid on the pile heads
- Longitudinal beam — a continuous beam running along the wall, on top of the kespen
- Plank or board layer — sometimes added as a distribution layer
- Masonry or wall — the rising wall sits on this timber base
By spreading the load via the kespen and the longitudinal beam, piles that are not exactly under the wall can still take their share of the load.
Application
The Dordrecht foundation was mainly used:
- In the 17th–19th centuries in cities in the western Netherlands
- For canal houses in Amsterdam, Dordrecht, Leiden, Delft
- On soft peat and clay soils where shallow strip foundations were not possible
- Under churches and monumental buildings
Problems
Many Dordrecht foundations now show problems caused by:
- Pile rot — timber piles decay when the groundwater level falls and the wood is exposed to air
- Pile plague — bacterial decay of pine piles
- Settlement — due to rot or differential movement
- Foundation repair — often required, using concrete or steel piles
Related terms
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