Habitat for Humanity recently announced that they have completed, in partnership with additive construction company Alquist, the first 3D-printed owner-occupied house in the world. I'm pretty sure that I've seen other 3D-printed homes kicking around, but this is still a big deal and one of the first of such homes for Habitat for Humanity. (It also 3D-printed a house in Arizona this year, but I guess that one wasn't owner-occupied.)
The 1,200 square foot three-bedroom home is located at 129 Forest Heights Road in Williamsburg, Virginia. And it was "printed" in just 22 hours, which Habitat and Alquist are claiming reduced their construction schedule by approximately weeks compared to a traditionally framed house. Overall, this translated into an estimated savings of 15% on the total construction costs. (Again, according to Habitat and Alquist.)
These kind of savings are particularly important in many rural communities where it is not uncommon for homes to sell below their replacement cost. Not surprisingly, when you have a market dynamic like this, there's zero incentivize to build new. I mean, why would you when you can just buy something that already exists for less money, and with less risk.
Alquist uses a patented concrete to print its homes. The concrete can be left exposed, or it can be finished with traditional building materials. For any load-bearing or structural walls, I understand that they print two walls with a cavity and then use typical reinforcing bars. I would imagine that this approach is particularly helpful when lumber costs are high, but there's an obvious question around embodied carbon (concrete in lieu of wood).
Still, it's hard not to believe that we will be seeing more, rather than less, 3D-printed homes in the future.
We tend to think of buildings as being very permanent structures. After all, our cities are filled with buildings that are hundreds of years old. And in some cases, much older.
But the reality is that buildings, just like everything else, depreciate over time. They have life cycles and they need to be regularly maintained and periodically renovated in order for them to survive.
This morning I was reading the blog of Witold Rybczynski, who is an author and architecture professor at the University of Pennsylvania. A few months ago he wrote a post talking about the short life cycle of modernist buildings.
According to a recent colloquium at the Getty Center, the average life span of a conventionally built building (masonry and wood) is about 120 years. But for modernist buildings (reinforced concrete and glass curtain wall) it’s half that: 60 years.
And if you are to consider the typical big box retail store, the life expectancy is probably a third of that – if even that. Usually it is cheaper to just tear down the old box and build a new one when needs change. That’s part of the reason why the leases usually have clauses that try and prevent the retailer from just “going dark” and stopping operation.
So we are literally not building them like we used to. And there’s a lot of debate in architecture and building circles about whether or not this poses a serious problem for cities. It is clear that Witold is unhappy about this shift.
I am a strong believer in heritage preservation. I believe wholeheartedly that cities are far richer with layers upon layers of history. But I also acknowledge that in our world of 6 second Vine videos, we seem to be less worried about whether something will last 60 or 120 years.
Perhaps that’s a problem. Or perhaps the times are just changing.