We very easily talk about sustainability and circularity in construction. But what do we actually mean by that? Ronald Rovers sets the definitions straight.
Let's start 2026 with a good intention: we make the right agreements on definitions. Because some of the definitions we use a lot in construction are misleading. And if we keep using them, you might also misunderstand my columns.
Take 'sustainable building' for example. We banish the word "sustainable. Everyone understands it differently. We should never have introduced that word, although I admit that I am also responsible for it myself. We had better go back to "environmentally conscious building," as we called it in the 1980s and 1990s. Or better yet, FULLY. The essence of that is that what we do is sustainable. Is energy and material use still possible for others in the future and can we use it for replacement?
Aha, the latter is circular, right?" you say. Unfortunately, the term "circular" is also misused. Most use the word to suggest they are, when in fact they are not. Circular is only that whose stock is recovered within the time of use-application. Then the cycle is closed. This applies almost exclusively to regrowable materials from the biocycle.
For circular as in "circular economy," this does not apply. In it, the word 'circular' is also used for raw materials whose stock is not recovered in time, such as metals and minerals. So that is improper use of the term, and therefore misuse. Because in fact, all those supposedly circular steps revolve around extended use, or linear slowing down. Nothing wrong with that, but circular it is not. There is still depletion, just a little slower.
With some good will, you could probably still call this "renewable," or in Flemish, "Renewable. The raw materials are 'renewed'. But then that could apply to anything. Moreover, it is confusing in relation to biobased resources, the supply of which is being restored, in the sense of being truly circular. 'Renewable' is therefore also no longer used.
By the way, solar energy is not renewable either; it's a constant stream, burning itself up and one day ending. It is, in other words, flow energy. Just like wind, hydropower and even biomass energy.
As far as raw materials are concerned, I suggest that from now on we speak of RE-GROWABLE and RE-USABLE. Something is regrowable if the substances actually regrow and if the stock can therefore replenish itself within the time of use. That is an autonomously driven process. And then we use "reusable" for the rest, requiring human intervention to accomplish the process of "extended use. That is much less confusing.
Oh yeah, and CO2, of course that's just an end-of-pipe approach. CO2 is just one of the effects of energy use. It is better to ensure strong energy reduction, then several drawbacks, including CO2, disappear.
So we are going to be working in 2026 to use regrowable and reusable raw materials, with flow sources for energy and all in a sustainable way. Right?
Ronald Rovers
Ronald Rovers is an ex-professor, physical fundamentalist and future thinker. He is on a quest for the ultimate sustainable physical balance on earth, without fossil of course. Productive Land he sees as our real capital, for food, energy, water and materials. That requires that we live 'vegetarian', and thus also build vegetarian. In that light, he explores the future of construction here.
