Hi all, has anyone come across a comprehensive (and recent) study looking at how long buildings actually last (beyond Stewart Brand)? I know of plenty that look at the benefits of reuse, but none that look at existing building stock and how much has been reused vs. demolished.
As we start looking at embodied carbon metrics, I can't help wondering about what percentage of buildings are actually adapted/reused (or will be). Just because we plan for a 200 year lifespan (and thus use higher embodied energy materials) doesn't mean they do last that long--the pancake buildings of the 70's are being razed and replaced with higher density uses (that's good); parking garages don't necessarily provide the best housing or office spaces for adaptive reuse, especially if they're built for the lowest possible cost.
Even better would be a study that looked at building stock, quantified what was kept/demolished, and then summarized the qualities of what was adapted (higher floor to floor, access to transit, etc etc).
I know there are plenty of examples of timeless buildings (hello, SoHo and most historic city centers)--but they're the exception, not the norm, particularly for most US building stock built after 1940. I guess I'm struggling with whether there should be a cap on projected lifespan (say, 50 years, since you'll be replacing all of the major systems and regenerating the envelope), or some sort of metric for discounting lifespan based on location (low density suburban development should cap at 25-30 years; high density and transit-connected urban development would anticipate a longer life). Or by client type--higher education institutions tend to keep their assets longer than developers, for example.
My hope is that this kind of analysis could inform both durability and embodied energy discussions on projects.
Any ideas?
