Natural vs Sustainable - Sustainable building materials, Part 1
Originally posted 20th February 2020
UPDATE! There is also now a short film version of this blog, which you can find here: https://www.sustainablebuildconsultancy.com/blog/natural-vs-sustainable-in-film-form
The word ‘natural’ is often used as shorthand for ‘sustainable’ - but should it be? Is a natural building material automatically sustainable, and are the only sustainable materials natural ones? What does the word ‘natural’ really mean anyway? Come to that, what does the word ‘sustainable’ really mean?
I call myself a Sustainable Building Consultant, so these questions get to the core of what I do. In this series of short blogs I’ll explore some possible answers and discuss what really makes a building sustainable. I’ll have a look at some examples of building materials that are often called natural - and some that aren’t - and consider the various issues that define their suitability (or otherwise) for sustainable building.
The Oxford English Dictionary defines ‘natural’ as:
existing in or derived from nature; not made or caused by humankind
…
having had a minimum of processing or preservative treatment
That first definition is problematic in itself, as it ignores the pressing reality that humankind does not exist in a bubble, separate from nature. Human-made or natural, anything that exists takes physical form from the same finite resources available to construct things from. So where do you draw the line between natural and human-made? The second part of the definition above attempts to deal with this: minimal processing or preservative treatment = natural. So does natural by that definition necessarily = good?
The less processing involved - the less energy is used in that processing, which is a point towards increased sustainability. But with a bit more processing, some bits of wood (for example) can be turned from a non-insulating material into insulating wood-fibre boards which can form part of a well-thermally-insulated, energy-efficient building. The energy saved from reduced heating in a wood-fibre insulated building compared to the very high heat demand for an uninsulated timber structure would far outweigh the extra energy used to process that wood into insulation.
When does the wood-fibre board cease to be natural? It’s often referred to as natural material in deference to the fact that the source material (wood) is naturally-occurring, even though by that point it has undergone more than “a minimum of processing” - the boards have definitely been “made or caused by humankind”. By the same argument, couldn’t it be said that anything made by processing other naturally-occurring materials is also ‘natural’? This definition would then encompass plastics and other oil-derived products.
My point is: the term natural quickly becomes almost meaningless as a gauge of a products sustainability or suitability for use. It’s worth remembering that asbestos is made from naturally occurring minerals, and while it has many useful properties - it is highly toxic and rightly banned from use.
Next week I’ll look at definitions of sustainability, and what does make a material sustainable.
