I know this seems obvious when you think about timber-framed residential buildings: all the embodied CO2 is in the concrete and steel, so the bulk of it is used in the foundation.
But in bigger buildings, it’s not so obvious where the carbon cost is hiding. In a typical commercial building, just over half the embodied carbon is in the structure and about half of that is on the floors. Therefore the floors in an average American commercial building are about a quarter of the embodied carbon content for the entire building.
“The analysis also found that steel buildings had more embodied carbon in their structures than concrete or composite buildings.”
At last year’s PHI conference, the conversations were laden with references to reducing not energy but carbon emissions. Concrete and steel have significant environmental costs compared to timber.
—7 Jan 2020