Sustainable foundation - 27/08/2011


One of the most difficult aspects of optimum Cradle-to-Cradle design are building materials. During the preparation we inventorised what materials could be used best for what application. During this inventory, it turned out that there is still a lot of room for improvement in current practice. We think that real Cradle-to-Cradle design will only be possible in a few generations from now. We did nevertheless try to get the most out of it. One of the examples of this is the use of clay granules (Argex).

Argex granules are clay granules that expand when heated. Probably they are mainly known from the plant boxes in which they are often used.

Although clay granules have been used previously in different building situations, we were confronted with the fact that structural engineers and builders still have little experience with Argex. Technical details are not widely available and instructions for use and knowledge of processing speed cause much uncertainty in the preparation stage. We decided to stick to our plan and use the clay granules anyway. And fortunately, the processing turned out to be easier than expected. Moreover, we discovered that the use of the clay granules had a number of other advantages as well, such as working in a clean way, which enabled the perfect fitting-together of the pipes and wires on the one hand and the insulation materials on the other hand. The clay granules that we have left, will be used later in plant boxes in the building.

We also considered how all the materials can be taken apart again at the end of the building’s life cycle. Because of the use of the clay granules, this will not be difficult at all. On the clay granules, a subsequent layer of concrete (see blog item ‘Concrete-free?’) was poured. This concrete layer could only be poured after foil had been applied on the clay granules. A sustainable alternative to this foil was not available, as it unfortunately turned out, so we had to use traditional polyethylene foil.

During our project we do not avoid risks, but we do carefully look at ways to keep them within acceptable boundaries. In this case, this has turned out well!

Bert van Helvoirt (

Van Helvoirt Groenprojecten
(landscaping projects) is currently realising one of the most sustainable office buildings in the Netherlands. For the realisation of this office, Building Team + was put together. Building Team + is a concept of Wim van Dijk of Klostermann Nederland BV and is realised in practice in cooperation with Bert van Helvoirt of SHFT. Therefore we will also write about this unique project on this website. The realisation process can also be followed on (in Dutch).