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Comment by wonder_er | Hacker News Reader

Rammed Earth.

I'd long been part of the camp that says "on the whole, concrete's not that great of a material to build with, for a bunch of reasons, but it's also got some significant upsides."

Then, I stumbled backwards into this crazy building technique that solves _some_ problems really well.

It's this traditional building technique called "rammed earth".

It's updated a smidge for modernity, but it's basically the same today as how buildings were built 1000 years ago.

Mega beautiful, practical, interesting constraints and opportunities, anyone can build them, etc.

Wikipedia: https://en.wikipedia.org/wiki/Rammed_earth

Video from a skilled modern-day rammed earth structure builder: https://www.youtube.com/watch?v=jijU-4A8jAk

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> Video from a skilled modern-day rammed earth structure builder

Note that the rammed earth there is being mixed with cement, making it in effect a lean concrete. Additionally, the column (?) is on top of a concrete footing, it appears from coloration to be a fairly normal concrete mix at the bottom, the top layer is also definitely a standard concrete mixture, the rebar looks like standard for something in a short building as that presumably is. Essentially the only difference between that and a standard concrete structure is that the column has to be much larger in cross section (as the lean concrete mix used would have lower compressive strength than normal concrete), the mixture uses less cement in exchange for compaction in lifts (i.e. exchanging material cost for labour cost), and the formwork has to be much heftier to sustain the pressures being placed on it from the pressure rammer.

I quite like the sturdier looking columns, and the layering is quite attractive (that guy clearly puts a lot of effort into it, visible when he's fine tamping the outside edge of the layer very carefully), but I don't think it's so much different than normal concrete. Trying to do QC or QA on that mix design would be a nightmare.

I think cob (think hobbit houses), similar, has been around longer. And there are examples of cob buildings lasting hundreds of years. I wish building code would let me get some friends together for some house sculpting . . .

https://www.motherearthnews.com/sustainable-living/green-hom...

https://www.homedit.com/what-is-cob/

https://www.buildingbuff.com/what-is-the-oldest-cob-house/

I've had the fortune of checking out a few rammed earth structures around BC, Canada (there is a cool fence/wall built with it within a property on Saltspring Island, a winery's sales building on Hornby Island, an amazing example in Osoyoos[1], and many more) and I agree, it's really beautiful.

If I have the opportunity I'll almost certainly use it to build a home in the future. I'm always excited when I see buildings using it. Well done rammed earth walls are absolutely stunning when finished properly.

1. https://sirewall.com/portfolio/nkmip-desert-cultural-centre/

Very cool!

Do you know how labor compares to more conventional methods? My understanding is that labor is often the biggest expense when constructing in America.

I wonder how difficult rammed earth would be to standardize. The Wikipedia article emphasizes customizing soil makeup to the local conditions and mentions the need for an expert to manage quality control. Basically I wonder how resilient rammed earth is against contractors cutting corners.

Related, compressed straw panels are a really exciting technology: https://www.greenbuildingadvisor.com/article/compressed-stra...

CEB, compressed earth bricks. I'm a big fan :)

Open source ecology has been using them in their builds over 10+ years.

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