New Story's first 3D-printed houses are now complete
fastcompany.com
fastcompany.com
Of course, this is Mexico, so I assume the equation is different. But in Mexico, at least they'll let you live in a shack-I-mean-tiny-house, so I assume this has to be somewhat competitive.
The possibility of using local materials for a 3d printer is enticing, however.
I'd have thought the virtues of 3D printing as a construction technique are much more to do with precision forming of unusual shapes tbh, which is the other end of the market.
Seems like they are just doing R&D at this point though.
You likely make it cheaper by using locally-sourced materials (gravel, sand, cement if possible) instead of transporting those. And you can probably pack the rest a lot more tightly than moving those air-filled walls around.
https://m.all3dp.com/2/cura-support-settings-optimize-your-s...
Looking at the photos of the houses, I wonder if they pause the printer at the point just before where it needs to draw the first layer above the top of the window frame. At that point a couple of workers manually lift the prefab window unit into place. Then the printer can resume and print that next layer on top of the top of the window frame.
That said, wooden and, more recently, foam forms have been used since forever. (At least a hundred years?) Breaking the forms away from cured concrete doesn't seem to be problematic.
EDIT: Also, in another video there's a brief shot where the machine is printing the internal zig-zag pattern over a steel mesh manually placed on the wall, presumably for reinforcement. I fast-forwarded through 4 or 5 videos and it's almost suspicious the way they avoid capturing these details. I guess such details don't fit the narrative they're selling.
There's got to be something in there that supports horizontal forces.
Personally I think they should emphasize the manual labor requirements. One of the strongest criticisms of 3D-printed and prefab housing technology is that it reduces demand for low-skilled labor. For the past 80 years home construction has been a major pillar of the American labor economy; likewise for China and many other countries. Free or reduced cost housing is great, but to the extent it comes at the expense of a sustainable labor economy, then it's problematic.
What is the barrier to affordable housing construction in rural areas? Where I traveled in Uganda it was availability and affordability of materials and equipment. Cement was expensive as was corrugated roofing. Renting heavy equipment was expensive.
We had plentiful cheap unskilled labour, free bricks made from clay soil baked in the sun, lots of hand tools and a foreman with basic construction skills. Transportation was slow but not prohibitively expensive.
I hope this 3D printing technique is simply a way of waving a flag to draw attention to the need for better housing in these communities. There are many much better MVPs than an expensive machine using expensive materials operated by an expensive team.
For this solution to scale, it has to be really good at dealing with whatever's available. This seems exactly the kind of "making square pegs fit round holes" problem that is suited far more to localized human ingenuity than automation.
Appropriate technology there is a hand-press for making TIB-style mortarless interlocking bricks from local dirt. (I have heard that Ugandan brick masons use way too much mortar anyway.)
The test site was likely in Mexico because building codes in the US have no provision for establishment and testing of new technology that is too far removed from existing construction techniques, such as inflation forms lined with rebar and sprayed with shotcrete, or 3D-printed corrugated-interior concrete walls. If the machine built 50 houses in the US, none of them could get certificates of occupancy from the inspectors.
The end goal is likely not to house the poor around the world, but to establish building codes that advantage the first-movers in printed-concrete home construction, so the patent-holders can build houses in the US that can be finish-ready for $5000, install windows, doors, electrical, and plumbing with assembly-line labor, and then sell for $75000.
I agree with your concerns over the way regulation gets us stuck in a rut. But from TFA:
"The same technology could also help transform the construction of affordable housing in the United States. Earlier this year, Icon printed a welcome center for a master-planned community in Austin, Texas, designed for people who have been chronically homeless, and the company is beginning to print 400-square-foot homes in the community that will be completed in early 2020."
By contrast though: I can design you a house that follows traditional design rules. So long as I use standard materials under the standard rules someone else has long ago done all the work to ensure the standard is right and so it doesn't need additional certification. It is quite likely I can violate something in the standard and still be safe - but then it is up to me to prove it is safe (I'm not qualified to do this)
Houses get around this because engineers figured out the limits - a 2x12 can up to (note up to not exactly!) span x distance under these assumptions. The inspector just verifies you met all the conditions and you are good. You can do this with any form of building, but it is much cheaper for one building to just certify that exact design. If you only have a half dozen designs it is probably cheaper to certify each separately, but eventually you have enough different designs that you just figure out the limits and rules and never have to worry about it again.
You might be able to do that on a single property with 50 identical copies of one design, but one at a time is unlikely. So you build the engineer certified designs and then lobby to get the method of construction included in the building codes.
Edit: Waterproof? Earthquake proof?
https://s3-us-west-1.amazonaws.com/contentlab.studiod/getty/...
But it would be difficult to find a house in Rawalpindi, Pakistan that isn't composed from some combination of locally made small bricks, concrete blocks, concrete and cement.
I know a number of people that had never seen drywall, the building material, before immigrating to north america.
Only in North America have I been told that I woke someone up in the middle of the night because I opened a door or got a glass of water from across the house because the house creaks and drums when you walk across it.
Concrete blocks can be produced locally with rather simple tools. It also has benefit that it may provide work to local people. In poor regions, labor is cheap and creating workplaces is always benefit to local commnunity, so I wonder if automating this out is positive thing at all. I'd like to see comparison of costs/benefits for houses built like this vs more traditional construction. Don't get me wrong, I love tech toys, but this looks very much as a solution looking for a problem.
The nozzle that deposits that concrete is just guaranteed to be much more fussy about quality control than the guys shoving it into moulds to make blocks. So it'll need high-quality materials transported from somewhere, not whatever is lying around.
This page mentions $15/sq-ft, and declining, so a 500 sq ft home would be $7500. Or 100 months of average income in this part of Mexico.
I think since donors have to feel good about themselves they won't just donate concrete and bricks.
And since NGO's can't build houses that are not up to code they can't just use local labour.
So this might work.
Earthship houses have shown after decades of having a cheap house design with cheap materials, that's not enough to solve the problem. Watch the docos read between the lines.
The actual benefit here might even be the fact the NGO makes the government give land titles for under the houses.
Is that one a special type of concrete? In places where earthquakes occur I would expect some kind of reinforcement to that concrete mixture, or it would crumble very easily at the first hit, but from the article it doesn't seem they're adding iron bars or any similar reinforcement.