Fraeylemaborg is an estate of 23 hectares in the city of Slochteren (The Netherlands). The main building was originally built seven centuries ago but it got its final form at the end of the 18th century. During its lifespan, a number of important families lived on the estate. The last owners, the Thomassen à Thuessink van der Hoop van Slochteren family, sold the estate to the Gerrit van Houten Foundation in 1972 and it became a museum. In the museum you can still see how the last owners lived. Temporary art exhibitions are exhibited in the Coach House. The current museum does not have enough space to show her entire collection and therefore the museum issued a competition for several new exhibition follies to display special items. The copper chamber is one of the follies to be built.
Our design is the second project from a series of five different projects. We want to research the possibilities of foam as a freeform building material using a CNC hot wire foam cutting machine.
The current building industry is based on an orthogonal building practice. Bars, plates and blocks are produced to build rectangular buildings. The further the design derives from the orthogonal system the more difficult it becomes to build the building and the more waste material remains. That makes producing free form and parametric architecture expensive and environment unfriendly. A future solution could be the 3D printing technique. A 3D printing process has the advantage that it hardly produces any waste material regardless of the complexity of the design. Nowadays the 3D printing technique is starting to become a designer’s hype where all kinds of small daily objects have their 3D print version. The technique perfectly coincides with the individual centered society that we are part of these days. The disadvantage of the existing 3D printing technique is that the technique is rather slow and therefore only suitable for small objects and prototypes where speed is not an issue to consider. Within the architectural practice, the 3D printer is only used to produce models. It would take years to print entire buildings with the existing techniques. Universities and some builders are working on faster techniques but the results of those experiments are so rough that they will need a lot of post processing in order to make acceptable buildings. Current research is focused on printing stony materials like concrete or composites. The printed elements will be suitable as wall-panels or structural elements, but to be able to print an entire free-formed building, all components have to be free-formed; the structure the insulation and the skin. It will take a long time before the industry is at that level.
Perhaps an alternative solution needs to be found in the meantime. As an office, we have been looking for a computer-controlled technique with similar form freedom as the 3D printing technique, ready to be used but fast enough to compete in the building industry. The technique should produce building materials that combine strength and insulation properties. The most suitable material is EPS foam blocks. The material is cheap and with the use of a CNC hot wire foam cutter it can be cut at high speed in any form you want. When covered with a material such as a Hot Spray coating, the combination will form a sandwich structure that enables you to make small buildings or entire wall panels.
A CNC hot wire foam cutter works through a heated wire. To cut the foam, the temperature of the wire has to be above the melting point of the EPS foam. If the temperature and the speed of the wire are adjusted well the wire does not touch the foam but burns it away before they meet. The advantage of this system is that there is no force implemented on the original material (EPS foam) giving the technique high precision. Both ends of the wire are connected to pace-engines that are controlled by a computer. In the machine that we use, both ends of the wire can be moved independently which makes it possible to cut twisted surfaces. By selecting the surfaces carefully it is possible to make virtually any form.
The Copper Chamber was parametrically designed on the computer. We used a Grasshopper script to design a folly that can be theoretically cut out of one sheet of EPS 300 foam sized 4,5 x 4,5 x 0,5 m without leaving any waste material. The folly is cut in layers. The first outside layer is a square; the top layer (in the middle) is in the form of the Fraeylemaborg estate silhouette. All layers (the rings) are cut with one slice. The rear surface of the wall of the lower ring is the front surface of the wall of the layer above. The thickness of the wall is variable to enable twisted surfaces. Hot spray will glue all layers together and fix the structure to a concrete slab. The weight of the slab will protect the pavilion from lifting in the wind. The outside surface of the folly will be coated with a copper coating.