Concrete pole foundations

As for any other type of house, our wooden houses need a foundation. And foundations are a very local thing, in that the actual construction is very much dependant on the local conditions. In the Alps and the Pyrenees you need to drill away rocks until you have a flat surface. In The Netherlands everything is already flat, but usually soggy so that your house will sink and disappear in the mud.

In many parts of France hillsides are subject to land erosion and you need all kinds of special drainage and other system to make sure your foundation does not accelerate the erosion with your house ending somewhere at the bottom of the hill. Plenty complications, and for sure you need locals to build a good foundation.

Here we show you how, in some parts of the Netherlands, they build a foundation. The idea is simple: the top layer is mud and you can’t build in the mud. So you take a concrete pole and hammer it into the mud, all the ways until you hit a hard layer of sand. Yes, a layer of sand is hard, hard enough to support your house.

So where is this layer, at what depth? That depends. Ground research will tell you. In some areas you will find a layer after three meters, in other parts you will have to keep hammering your concrete pole into the mud until you reach a first layer at 25 meters. Fortunately it is hardly hammering, the mud is soft and the pole will easily go down until it hits the sand layer. But, for a 25 meter pole, you need a hammering pile driver crane that is at least 25 meters high, so that’s not the cheapest model.

And also a 25 meters pole is not something you can easily throw on a truck for transport (your standard truck is max 13 meters long) so you will need special guided transport with pilot cars blocking other traffic and flashing yellow lights everywhere. Not cheap. At the time of writing (end of 2021) a foundation in The Netherlands will cost somewhere between 200 euro/m2 footprint up until 300 euro/m2.