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Comment by a1371 | Hacker News Reader

There are varying opinions about 3D printed buildings. When I was new in this industry, I thought they are the future. Even approached the UOSC for a position, but as the time went on, I understood how my tech background was influencing that thought process.

3D printing offers little advantage over prefabrication, yet it comes with many costs, biggest of which is embodied carbon from all the concrete pouring. NASA has the right mindset to pursue it on other planets, on earth our housing issues first come from archaic design and permitting processes.

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I love 3D printing. I have seven 3D printers and have designed a bunch of 3D printed robots.

But there is too much unreasonable buzz around 3D printed homes. Too many news stories act like this machine will somehow solve homelessness or some other breathless claim.

My contractor friend told me framing a house is cheap. It’s all the finishing work that makes a home expensive, and 3D printed homes still need that. Meanwhile I saw a 3 story apartment building that went up in Berkeley in two days because it was made of modules from China. It seems like homes made in a factory make way more sense than 3D printed ones.

Edit: I don’t want to be too negative. I can’t read the article due to paywall and I don’t know a lot about the technology. Certainly some reporting on this tech is absurd but the concept may have merit in time.

Not to mention the cost of land anywhere near good jobs.

In my country, if a 3-bedroom family home in a given town is worth X, and constructing such a home costs Y, the plot of land will cost X-Y.

I’d expect it to cost even more, wealth begats wealth. Since Europeans started to define owners of the land 400 years ago the population of the US has ballooned, the land hasn’t. Those whose ancestors acquired land are in a far better position than those who didn’t

Somewhat related, in the US at least, homesteading wasn't ended until 1976 (1986 in Alaska). A rather large percentage of the land was given away by the government after the act was passed in 1862. Of course, the concept of land ownership goes back thousands of years. [[the singer, Jewel, discusses growing up on an Alaskan homestead on a fascinating recent interview with Joe Rogan]]

> Not to mention the cost of land anywhere near good jobs.

It does help that most 'good' (significantly more than living wages) jobs can increasingly be done remotely. I worry more about the cost of land near 'ok' jobs (at/slightly above living wage).

Homelessness is a political problem not a production problem.

I think it must be 5 years ago that I saw one of those prefab houses going up. I saw a crane being brought in at like 8am in when I had my drive to the office and when I came back home at 5pm there was a 2 story house where the crane stood.

> Homelessness is a political problem not a production problem.

Mostly agree, but certainly a significant drop in the cost of addressing the problem would make it more tractable, politically. That said even if the production problem was addressed, the land cost would exist, and no matter how low the cost is there would certainly be some politicians unwilling to fund it on 'principle' (quotes because I really mean spite)

The land cost for housing is mostly political problem.

The land cost and the zoning problems are orders of magnitude more of a problem than actual building. Granted right this second Raw materials are ridiculous but that's a knock on from covid problems.

Basically anything that doesn't need piece-unique mechanical design is better prefabricated than printed.

> Too many news stories act like this machine will somehow solve homelessness or some other breathless claim.

Could make blue-collar workers in the construction industry homeless when they lose their jobs. Some manual-labor jobs we should want to keep.

Ahh, but that’s an allocation problem. The goal should be people are housed regardless of the consistency of their work and income.

Like others in this thread have mentioned, the problem isn’t 3D printing versus factory fab, it’s the economic model on top of the physical system.

Not only that, but prefab on a literal factory production line can do a far more consistent job of what finishing is possible pre-assembly than you can do on-site. Yes, construction workers are good at this stuff, but they're unlikely to compete with TPS-style production line optimisation on cost or repeatability.

You can't even use rapid fabrication to set the plant up at the point of need, because wastage in the construction process means that it takes less energy to ship the finished product than the component parts you'd need in your supply lines.

http://archive.today/BxdfB

The main problem with prefab is transportation costs. It is not surprising that the homes were setup in Berkeley, which is near a port, since sending goods by sea is like 50-100 times cheaper per distance traveled than by roads. Plus sea travel cost comes mostly from weight, not size, so transporting bulky items with mostly air by volume is ok.

But for more inland travel transportation cost for pre-built modules becomes very problematic. It is much cheaper to bring dense raw materials. But then of course the issue is high building cost and 3D printing tries to address that.

Besides the fact that you have in the end a "worse" building compared to traditional construction or prefabricated, 3D house printing may be an idea in first world countries where you can this way reduce man work (spending instead on the machines/technology).

It makes little or no sense in less rich countries where not only workers are (relatively) cheap, but there is unemployment and hiring people to manually build houses actually contributes to the local economy.

If you want an example of (very fast) building "terrible" houses, there was the "balloon" method that dates back to the sixties (and is actually very efficient/fast/costy saving):

https://en.wikipedia.org/wiki/Binishell

Only for the record a "modern" approach to similar "dome" houses (but pre-fabricated):

http://www.i-domehouse.com/

Just like 3d printing plastic doesn't compete with injection molded plastics, 3d printed buildings don't compete with prefabricated buildings.

That is to say, if you're trying to build something expensively, and slowly, with a lot of compromises and flaws, 3d printed buildings are for you.

Even prefab arguably has little benefits compared to sourcing local materials. Traditional house building (with local earths or wood) can be very energy-efficient, and it's hard to beat locally-sourced materials from a carbon perspective.

Local earth into a 3d printer to extrude a sort of construction clay has been done, to complete the circle.

Do you maybe have links?

I personally know about making dirt bricks (pressing the earth) and about clay-hay mixes (traditional approach), but i have no clue about 3D-printing earths and what the benefits (or downsides) of that would be.

https://www.itsnicethat.com/news/tecla-house-mario-cucinella... is what I remember reading. The press release site is here: https://www.3dwasp.com/en/3d-printed-house-tecla/

The printer arrangement is quite interesting in its own right, they put gantries up in a sort of hexagonal grid: https://www.3dwasp.com/stampante-3d-per-case-crane-wasp/

From the banner picture on that page you can see part of the mixing kit: it looks like they basically mash local soil and a bit of water (with the option of adding hay, according to https://www.3dwasp.com/en/maker-economy-starter-kit/) to make a bulk mixture which is just pumped through a hose on a fairly conventional cantilevered arm.

The benefit is intended to be that you don't transport the construction materials at all - Km0, they call it - but you'd have to do some digging to find out how the physical properties compare to other techniques.

One major downside I can see of this sort of construction compared to almost anything else is that if anything gets damaged, I can see it being a right pain to fix.

Why so? Clay-hay is really solid, and if you ever make a hole, making a patch is as simple as making more of the mixture and applying it locally.

It's more that the designs you're likely to be building to take advantage of the fancy extruder are more likely to be the sort of thin-shell construction where holes anywhere cause structural issues that you wouldn't see with more discrete building elements. I was also thinking that if you've only got a hole in one face of a wall, you can't get to the back of the hole to support a patch, but I'm guessing that's less of a problem.

thanks for the link, that's pretty cool indeed!

however running 6KW to produce a small house is not exactly eco-friendly either, especially given that the machine's production has not been accounted for. from my experience, to produce clay-hay housing, 200h with a bunch of volunteers will get you so far as this machine, although building so high is trickier in a low-tech setting

don't get me wrong: i'd much rather have this kind of house production than concrete bullshit that pollutes orders of magnitude more. i'm just saying if we're going down this way we may as well do it "by hand" :)

Depends where the power's coming from, I guess. They do acknowledge that the generator is a weak point in the kit.

The one place I see 3D printing being particularly useful is when access to a site is very difficult, and moving in large items is nearly impossible. A 3D printer that could be brought in in smaller pieces and assembled would then allow good, unique construction onsite.

Such a thing should be possible. The next step (which perhaps exists already) would be site-specific methods of sourcing local materials to use for the printing. Surely there's some earth+plant mixtures that can have some brought-in additives that can result in long lasting, printable material.

Plus, it has no cost or scale advantage. The main cost drivers for houses are land purchase cost, material cost and taxes. Labor is significant, too, which 3d printing is not reducing, because the installation of the machines take more or less the same amount of labor as just building the concrete walls traditionally.

The only benefit of 3d printed buildings are extravagant shapes, forms and curves. This is not relevant to 90% of the population and only might be interesting to luxury buyers.

Installation should iterate down to "drive the flatbed with the printer gear up next to the site and press a button". But you're not wrong, there's very little benefit over traditional construction, mainly because of all the things - even during the part of the process the machines can do - that still needs human intervention.

Labor costs + automation savings = you don't understand the cost of projects.

Even if it's not prefabricated - what is the advantage over concrete forms? This is similar to injection molding vs 3D printing, however concrete forms are much easier to construct than injection molds. We also have the issue of site prep, roofing, insulation, wiring, windows, doors, etc., all of which are not 3D printed. You could have a 3D printer handle millwork, decorations, inlays, embossings, and things like that, but for the giant blocky structures it doesn't do much.

> NASA has the right mindset to pursue it on other planets, on earth our housing issues first come from archaic design and permitting processes.

I strongly suspect that in space the design and permitting will be arduous in ways that make the worst on Earth seem like a libertarian paradise by comparison.

I’m not certain, but I get the impression the bigger cost for most of us on Hacker News is the competition caused by desire to live near other people. If location stopped mattering, this 6 bedroom detached house with a pool

https://www.rightmove.co.uk/properties/69740740

wouldn’t cost less than half as much as this studio flat

https://www.zillow.com/homedetails/960-Market-St-210-San-Fra...

This does not mean that 3D printing houses will never be a big thing: I’m looking forward to “An Englishman’s house is his castle” being more than just a cliché, and it may help with the infrastructure projects needed to make cities bigger which would allow land supply to grow to meet demand, but I don’t expect buildings made this way to make western cities cheaper — if it’s cheaper than labour, then even though it will displace workers, the price difference only goes into raising land prices

What designs do you recommend?

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