(July 2011) Poor exposure for the German International Forum Design GmbH, responsible for the IF Design Prize awards. One of last year’s prizes went to a concrete masonry unit and the website states: „In contrast to natural stone, the eco-life-cycle of cinderblock is a plus: no strip mining of blocks from a natural environment and a positive ecolifecycle.“
That is pure nonsense. We have compiled a few facts regarding ecological aspects of natural stone. No figures – so everyone can easily grasp the content.
The IF Design GmbH statement implies that quarrying scars the landscape.
This is true but is also true for cinderblock and concrete. They are comprised of sand (with varying grain depending on the type) which also does not rain down from above. Natural stone usually produces craters mostly in mountains. Concrete strips the plane. Nature recaptures the area – plant and animal life are quickly restored.
But the energy used to produce concrete is much higher than needed to produce a comparable natural stone product. Concrete requires cement as an adhesive and cement has a negative ecological balance. It is produced in huge ovens. The branch is currently seeking ways to reduce energy consumption.
Natural stone is ready-made. It simply needs to be taken.
Transportation requirements apply equally to both materials.
Another important aspect in a product’s eco-life-cycle is its ability to be recycled. In this respect steel and glass e.g. have a better life-cycle balance. These can be melted down and reused if disposal was carried out properly.
Natural stone, on the other hand, can be reused but a certain amount of down cycling takes place to the effect that finally the stone turns to mere gravel – with manifold usage, albeit.
Concrete blocks, in contrast, usually have but one life and subsequently land in the refuse disposal.
But recycling of glass and steel is no easy task either. Each new life requires melting down, which requires a great deal of energy.
Only naturally growing products like wood attain top marks here.
As far as longevity is concerned, stone seems to be unbeatable as demonstrated by the Egyptian pyramids – impervious even to UV-rays.
But this aspect is not important in stone’s eco-balance. No-one builds for eons anymore. Buildings are conceived to last for one generation – about 30 years. Thus concrete and stone run neck-a-neck in this aspect of the race.
Hard to understand, then, how IF Design can draw the conclusion that concrete is superior to stone.
Link to the IF Design-site (German)