Hello! I work for a statewide historic preservation advocacy organization and we are constantly trying to prevent demolitions, of course. We are trying to get better at estimating the environmental impact of demolitions and the embodied carbon calculators are difficult to use for this purpose, as they are often very technical and don’t include historic materials (notably brick or slate in the one I was just using). I would appreciate any ideas about how to best estimate the impact so we can communicate that to the public in a way that is relatively easy to understand.
Hi Jordan,
It’s not usually the demolition itself that has the high carbon impact; it’s the construction of a new building, with (especially) new structural and new facade materials.
The demolition carbon emissions include:
- emissions from equipment on site (fuel and water for the demolition contractors and their equipment)
- emissions to transport the waste away
- emissions to process the waste (off-site)
As I noted, these are typically quite low. The UK has a guidance document you can access, the RICS Professional Statement on Whole-life carbon Assessment (2017). It gives some high-level guidance on how you can calculate the carbon emissions from demolition (life-cycle stages C1-C4).
If you convert everything to a per square metre basis, and you will build a new, much bigger building in its place, this will make the carbon impact of the demolition look trivial too.
I appreciate that most of my message probably reads like, “demolition doesn’t matter”. That would be a misinterpretation 
It’s simply that demolition is often relatively low carbon, so the carbon-impact of demolition isn’t the story you want to tell. It’s the carbon impact of starting from scratch, which really matters.
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