Since early times, the houses in Amsterdam have been built on wooden foundation piles[i] that are driven deep into the clay, peat, and water until they reach the first layer of solid sand. Even some of the trees in Vondelpark are supported on wooden piles to keep them from sinking into the marshy ground.
Old wooded foundation pile under Amsterdam Central Station
How long can a wooden pile remain in the ground before it has to be replaced?
300 years? 80 years? Until next week? The answer depends on many variables:
Quality of the sand layer
In Amsterdam, the first layer of sand lies approximately 12 meters below the surface. However, the quality of the sand layer is not consistent throughout the city. In some areas, the first sand layer is thinner than normal or missing entirely. As a result, the houses in these areas sink at an abnormal rate, and the foundations have to be replaced faster.