Bubble Wrapped Concrete! More fun than popping it?
October 12, 2010
Combining two of man’s favourite things!
Concrete is the world’s most used material after water on the planet and is here to stay for the considerable future. Bubble wrap is used for packaging…and for whiling away boredom by popping it!
There is a common perception that concrete is associated with the period of brutalism with monolithic structures that are austere. I quite like those qualities and have designed solid concrete facades in my previous university projects. One of my favourite buildings in London is the Barbican. The design incorporates different levels and terraces that are surrounded by the apartments and there are walkways suspended between the incredible columns and beams – massive even if they’re not elegant. But we’ve been learning to cast concrete in fabric that expresses its plastic quality to try and express elegance through material, process and form.
We discussed with Remo Pedreschi, our tutor, the results of previous workshops of which the fabric formwork technique was investigated. They produced a wall at the entrance to the school of architecture that has a series of concrete panels cast like a pattern book of textures and techniques that inspired our first casts.
Making an Imprint
A special characteristic of casting in fabric is that the weave imprints onto the concrete. A bulge is expressed as the fabric is tensioned under the mass of the concrete and depending on the fabric’s elasticity the size of the bulge can be controlled. The surface can also acquire the pattern, dye and any stitching on the fabric. Surface texture is associated with shadow, light or even a change of temperature, abrasive or smooth to touch. This offers new possibilities for expressive and spatial characteristics that we shall be exploring in an architectural project towards the end of the unit.
The Bubbly results
Bubble wrap is extremely stretchy. The weight of the aggregate pulled the staples out of one side of the frame and we were unable to fill it up to the top, which made the edges very brittle. The concrete, once poured, requires rubbing to draw the smaller particles forward and remove air pockets. However, the water was unable to be released through the plastic so it took a few days to cure and when we came to ‘peel’ it the concrete was very dark. The edge condition was defined by a layer of celotape stuck around the edge of the bubble wrap. This gave a shiny flat edge in contrast to the bubbles although it was very brittle because of the lack of concrete at the edge of the frame.
The results were brilliant! Each individual bubble had made an intricate inverted imprint on the surface, even the dimples on the bubbles were expressed. What was more remarkable was the contrast between the bubbles against the plastic between them – which was incredibly smooth and shiny. The bubbles were also stretched along the side where the staples had come away from the frame, expressing the forces that had acted on the material as it sagged.
Development – controlling the bulge.
In a second test we aimed to control the amount and area of deflection of the bubble wrap whilst developing a contrasting smooth edge condition. We layed the bubble wrap onto some tough and relatively inflexible geo-texile fabric that prevented the bubble wrap from sagging whilst still expressing the texture. We stapled a cotton fabric boarder around the edge and carefully filled the frame and worked the concrete to improve the surface finish.
Within a week had learnt a lot about the possibilities this technique and the basics of manipulating the bulges and textures. We made other text panels that shall be discussed in the next blog before commencing work on a minature column – which involved the exploration of stitching and sewing formwork to manipulate form.