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3D-Printed Homes for Sale in Austin (lennar.com)
62 points by alexvomwald on July 3, 2022 | hide | past | favorite | 99 comments


Here's an actual house built that way.[1]

They just pour the concrete on. There's no compaction or smoothing. So you don't get a flat surface. A "print head" that compacted and smoothed to make a flat surface would be more useful.

Like this simple curb making machine.[2] This is the size for making garden boundaries. A bigger machine with automatic guidance is [3]. This is making a mall parking lot. Both of these will make a nice, flat concrete surface.

[1] https://www.iconbuild.com/updates/icon-unveils-its-next-gen-...

[2] https://youtu.be/A06vfELMIK8

[3] https://youtu.be/UCgma2_u_E8


I wouldn't call that an "actual house" since I don't think anyone lives there. But you can walk past it in the neighborhood. It looks nice. Iirc, the company building these has several lived-in houses in a community to get veterans out if homelessness, as well as a village where there was high-magnitude earthquake that levelled all of the houses except the ones that were built by them!


This might be one of those 'we made it look weird so everyone knows what it is and you can feel smug about owning it' things like stupid looking car prototypes, early electric cars (i3), white in ear headphones, recyclables, patagonia vests etc.


I would like to be excited about this, but I feels it's gonna end bad.

Currently they are not selling 3D printed homes, they are selling the "novelty" idea of one since they don't show any real one built, only crafty 3D renderings with photoshoped people. That's "normal" for your regular cookie-cutter development because everybody knows what to expect from those types of homes, but in this case the risk seems too high and I'm sure this is a pay-now-get-home-later type of deal.

Also, what's the problem 3D printing the walls solves? That's an infinitesimal part of building a home and from a cost perspective it barely moves the needle.

Sorry for the "party-pooping" but this looks like me selling a house that I've painted with my bare hands with no brushes, only knuckle painting.. cool, so what?


Party pooping is what HN is for and why I love it so much. It makes you grounds these pie in the sky ideas in their benefits.

One thing I would say is that the price of concrete, lumber, other materials used and labor have been skyrocketing. At some point in the future, 3d printing may be utilized to great cost savings.


ICON has been building houses like that for a while. You can find walkthroughs of their houses on YouTube to understand what to expect. https://youtu.be/vcSaUXViD9g


What walk-though? That's an hour of people sitting on a couch and talking.

I wanted to see how they did wiring and plumbing.



These videos were really neat and I'm much more convinced of the utility of 3d printed houses.

The Icon team that's actually building the houses seems like they're really intelligently applying the 3d printing as a technique. They're actively experimenting with figuring out where in an overall build it makes sense to use it and how best to handle the realities of adding in electricity, plumbing, windows, etc.

It's pointed out several times in the videos that we in the US are building residential housing predominantly out of wood framing just because we historically have had so much wood around.


Came here to say this, was not disappointed.


I laughed at the marketing material mentioning a labor shortage as a driver of this technology. As far as I can see, they only print the walls. The foundation, water, electrics, and roof are all handled by labor.

We watched 2 guys frame two three story houses next to us over the course of several weeks. They each had a house and would help each other at certain stages.

Precut lumber and prefab parts in exact amounts were dropped off on pallets daily and a cherry picker with a forklift end was brought in to put the pallets on the second and 3rd stories.

Once these houses were framed they had another duo each for water, electrical, drywall, etc.

It was incredibly efficient imo. They had a staging area for the entire neighborhood where the pallets were dropped off and one guy driving around delivering pallets to each team.


Damn that sounds so cool to watch


yeah I'm kicking myself for not setting up a timelapse camera. it was impressive.


It's probably more accurate to describe this as a new way of pouring concrete than as "3D-printing a house" in full. It's using concrete shot out from a printer head where concrete block or poured concrete might have been used. But most of the materials in the house are the traditional kind and will be installed in the traditional way.


You might even call it a poor way of pouring.


A solution for no problem. Thinking about building couple 80 square meters homes for rent right now and choosing the way I do it. Walls were and are the cheapest component. It absolutely does not matter if I take bricks and insulation. Or a bit more expensive prefabricated panels. Or pick classical wooden house. The costs for walls are less than one fifth. Maybe even 15%.


10-15 years ago prefab homes were going to be the new thing, built efficiently in a factory then inexpensively and quickly assembled on site. And yet the total cost was almost always more than standard construction. Now it's 3-D printing. Ok, sure.


Difference is that the prefabricated construction techniques actually do tackle the entire build, and allow time consuming bits like foundations, roofs, plumbing/wiring and kitchen/bathroom fitting to be done in parallel (it just doesn't scale particularly well to individual homes built on lots where on-site time isn't a major issue; city centre hotels are a different story)

This just tackles the low rise exterior wall bit - usually a fairly quick and uncomplicated bit of the build with a lot of options - and more specifically replaces the quick and basic technique of pouring concrete between wooden boards with highly sophisticated machinery and tight tolerances. The one thing it does do very well is permit complex shapes that basic poured concrete casting or off-the-shelf cladding can't achieve - but sculpted forms in concrete is a pretty small niche in residential construction, and much more of a high end architect request than a baseline for building homes efficiently


Yeah, this technique definitely has a techno-cool factor, but it just isn’t replacing particularly difficult or time consuming portions of a build. It appears that if you want 2 stories the second story is stick-framed (as are the interior walls) so you can’t even avoid hiring framers entirely.

Having a new house built now and of the roughly 7 month schedule, framing, sheathing and wrapping with WRB is less than 2 weeks.


This 22-unit housing complex was built in four days from prefab units. https://www.panoramic.com/cityspace-location/shattuck-berkel...

"... the cost of trucking [the modules] to Berkeley from the port of Oakland was more expensive than the cost of shipping from Hong Kong."

https://www.berkeleyside.org/2018/08/02/prefab-housing-compl...

https://sf.curbed.com/2018/8/6/17656118/fast-apartment-resid...


For the most part, those cost differences are due to US trucking being expensive and international shipping relatively cheap rather than anything specific to the modular construction. The same material (actually more due to waste) has to be transported to the site if you use different methods of construction. The need to fit on the back of a truck imposes an upper limit on the smallest dimension of a room if they're shipped as full rooms and not flat packed wall units, of course, but that's unlikely to be an issue for student apartments in Cali.


That would not be true today, with $40k container costs.


I am less skeptical since they're 3D printing concrete rather than wood.


But the structure is the easy part. The hard part is literally everything else, and 3d printing concrete doesn't make that any easier from what I've heard.


The home 3d-printing machinery (e.g. Vulcan of ICON: https://www.iconbuild.com/vulcan ) is huge, it's a 10,000 lbs machine that requires specialized equipment to transport, specially trained staff to operate and maintain, and in test runs so far they're only printing the first floor, so all homes built are a hybrid of 3d-printed concrete structures with wooden ceilngs and second-floors, and concrete floors made the conventional way.

If you're thinking of making a conventional home, it'll be considerably cheaper making it the conventional way, 3d-printing it will no doubt be substantially more expensive.

But the reason why one would want 3d-printed homes (i.e. just the first-floor wall structure) is because of some interesting possibilities: extremely high energy efficiency without effort, unique designs that can whether extreme climate events, air quality (concrete doesn't invite mold like wooden structures do!) and other nifty things like futuristic and organic designs, curved and sloped walls.

I'm pleasantly surprised by what ICON has accomplished. I see potential for this to become valuable when making bespoke energy-efficient and densely-packed neighborhoods. And I think after more ideas and workflows emerge to wrap up and finish a full house, it might become a commonplace technique for developers to make use of.


The cement industry is one of the biggest producers of CO2. https://en.m.wikipedia.org/wiki/Environmental_impact_of_conc...


Curved and sloped walls sound cool until one realizes that everything that one would want to put on those walls is meant for flat ones. TVs are flat, couches and cabinets are rectangular, etc.


And potted plants ?


>concrete doesn't invite mold like wooden structures do!

concrete absorbs water.


Poorly insulated walls lead to water condensing in the corners. In fact, concrete buildings are more prone mold during cold winters than anything that is properly insulated.


One of my former colleagues (Michael Holm, member of the Kefrens demo group on the Amiga ;) was one of the founders of COBOD in Denmark. They have partnered with PERI, Cemex, and GE, and most 3D printed building projects I have seen use their 3D printer.


Just saw that the Austin project uses an ICON printer, not the COBOD one.

Btw these "layered" walls would be terribly unhealthy to live within due to dust collection over time.


ICON homes are coated with elastomer paints at the end so I don't think dust coming off from layered walls will be a problem, if that's what you meant.


How environmentally friendly is concrete? I've heard cement is responsible for 5% to 8% of CO2 emissions globally.


Fun fact: Txdot, who spends 97% of their entire massive budget on expanding freeways, is responsible for .5% of all global carbon emissions.


That’s astounding. Are there similar figures available for other recent huge builders (e.g. China, both road infrastructure and dams etc)


Yeah, this was my question as well. Obviously wood has its downsides as a building material, but it seems to have some obvious advantages when it comes to renewability and sustainability.


Mostly public works projects, iirc. Housing is not a big contributor.


The issue here, along with all 'modern' construction methods (eg sips) is that without 50 or so years of data it's nearly impossible to get home insurance at a reasonable rate, and no insurance means no mortgage.


Seems like an incredible opportunity for a combined fintech/civil engineering startup. You can forego actuarial tables if you have a decent enough understanding of the building process to estimate what the failure modes are going to be.


> fintech/civil engineering startup > You can forego actuarial tables

Please no. Mortgages inevitably get resold to investors. The last thing we need is another 2008 because half the new houses built start crumbling after 10 years


here's what I see:

1. opportunity for the maker to have their own financing programme, and hopefully be very affordable for the avg person, maybe even programmes for the poor, another for young families

2. If this kind of house works well and sells, it won't be the bank that funds it... they'll spin up or buy out a fintech start-up that takes on "riskier" mortgages

lots of opportunities everywhere, but we should have way more of these 3d printed homes. it should be accessible to all for a fraction of the price of a "traditional" home in the same way that prefab homes which are now overvalued and overpriced were for our parents. we need this tech to be open sourced


Most mortgages still get packaged and sold in the form of ABS or to Fannie and Freddie. I think you’d end up with an inability to package them unless you could convince the feds and asset managers that they can consistently survive the lifetime of the mortgage.


Seems like an opportunity to create an FM Global like company for home insurance. Basically their business model depends on combining engineering and risk analysis.


All of the examples I can find using this technology are one-story. That's not promising for addressing housing price problems in large cities. But maybe it could be adapted?


My two cents having 0 experience in building construction but having a fdm 3d printer is it's simply a 'market fit' optimization.

It's a pretty new technology, at this point I think you can mainly hope to sell them to enthousiasts. Why bother with the increased complexity and risks of handling more height ? No one would buy multistories building with unproved technology, we have to wait year to see if the structure is really stable 'on often surprisingly complex real conditions'. And probably like 'small' 3d printers : the more maximum volume you want to print, the more cost heavy is the printer.

I'm pretty sure if it prove itself efficient over time, they will try to develop multi-stories buildings.

A current battle in 3d printing :

https://3dprintingindustry.com/news/crowdfunding-campaign-la...

This kind of printer have been theorized to be able to be put on cranes and one day print buildings.


Yeh I think that's all the 3d printing homes I've seen. I think one problem is that the printing setup doesn't have a way to put reinforcement in. I'm not sure if that's a problem for 2 story. Another thing they seem to have here is the gaps for windows; I think they're doing simple U's for the windows, so can't put anything on top of it.


There has been a lot of discussion about 3D-printed homes over the last 3 years with multiple companies getting funding.

One of the biggest home builders in the US announced a 100 home community in Austin and homes are expected to be available for sale soon.

What are your guys thoughts? Do you think a 3D-printed home would be a good investment?


The bottleneck in home building has never been the building of the home itself, but rather the permits and zoning regulations imposed by NIMBY cities.


The problem is more appraisers and banks that don’t know what to do with a lot of construction outside some norm, so they won’t know how to value and won’t know how to write loans.

And under circumstances of any substantial demand for their services, they don’t have incentives to change — they make more spending a predictable amount of time on activity they know how to collect fees for.

You could take all the city zoning/codes/ordinances away today, every last one, and you’d still have this problem (and lose whatever regulatory benefits might come with them).


at least for now and foreseeable future, there is a bottleneck right of labor.


If it slashes housing prices substantially, then yes. People want inexpensive houses. I'm not really into the idea of buying a house, but I would seriously consider buying one of these if they were inexpensive enough.


Only If they are quick to build, cheaper to buyer and long lasting...


Much as this is innovative I cant help but notice there isn't any insulation in these homes.

Sure, you have 6inches of concrete, but that just makes it more expensive to build.

From what I can see, its probably cheaper and quicker to pour ICF(https://en.wikipedia.org/wiki/Insulating_concrete_form). They are basically uber insulative, super quick to build, and support multiple floors in one pour.

The only way I can see the "3d" printed approach being either Eco(cheap) or Eco (earth friendly) is using doing a rammed earth/adobe system. At least then you only really need to dig up earth, power the machine, and boom, you have walls.


According to this[0], there is insulation filling the gap between the inside and outside walls.

0. https://youtu.be/QCWKJvsqjb4?t=549


I wonder what it takes to change the layout of your house. Removing a wall seems a lot more difficult when there's 6 inches of concreate than a traditional home.


Could they have a second print head for expanding foam?


Cavity wall insulation would be easier


Here is a video of Icon's CEO (the company building this community with Lennar) explaining more about the company https://www.youtube.com/watch?v=63uhYWkictE

It's a bit long but worth watching if you're interested in this technology.


Stupid question: Why use Gable roofs? Looks? Gable roofs keep snow off your roof which could cause dangerous load. Why would that be necessary in Austin or FL? Can we please just have 14ft ceilings instead? (I am typing this in FL next to a useless fireplace).


It’s not just for snow. In general, moisture management is a huge deal in construction, and having a surface that naturally causes water to go away rather than collect is a boon. You CAN do flat roofs but they are more expensive and complex and require more maintenance, so you for residental applications the trade off against useble roof space doesn’t make sense.


Why would you want 14 ft ceilings? That sounds awful.

With gable roofs you can put mechanical systems / ducts up there and use it for storage, especially if the attic is within the envelope of the home.


I have 14 ft ceilings in most of my house. It’s great other than the heating and cooling bill.


Austin has snow. There was actually quite a lot as recently as February 2021 when Austin got 8 inches of snow in a few days.


The Construction Physics blog convinced me it's not all an empty fad, but is clearly plagued by problems currently:

https://constructionphysics.substack.com/p/3d-printed-buildi...

There's also a lot of potential for 3D printing in construction in general. This 3D printed beam idea certainly seems interesting and worth testing out:

https://www.minimass.net/


Sounds like vaporware in the short-term. Are there any shipped 100+ unit 3D-printed communities already out there?


This will be the first...


Good luck putting furniture against those curved walls.

I don't see how this is any better than prefab concrete panels.


I've been invited in the building of several masonry homes. 3D printing is mostly good for putting up walls. Walls are quick, easy and require relatively little skill if you use modern thermal bricks. Comparatively, just about every other element is much more trouble.


Could you explain more about thermal bricks?


so... there's nowhere here where i can buy one of these homes. i think it's more accurate to say "real estate developer wants your email so they can maybe send you info about when 3d printed homes will be printed, but probably also to send you spam."


Are they substantially cheaper? That’s what I need right now.


It might have been a few months ago, when prices of lumber reached their historical peak. Concrete houses are more expensive than wooden ones because of the material and labor costs. "Printing" might save something by removing some labor but the machine they use is not free so you need to amortize its cost. And the walls are a small part of the cost of the house so even if this construction had been significantly cheaper, it would be a small difference in the total cost.


The structure of a home is typically 10% of the cost. If you want a cheaper house, make it less complicated and use simpler finishes.


I'm currently working as a trim carpenter, and sometimes even I think that, "oh, I could build a house someday". But then I stop and look at how much work actually goes into building a house, and check my ambitions.

For a small house, we (two of us) might spend a week and a half installing the hardwood floor, doors, baseboard, window trim, crown moulding, closet shelving, stair trim, etc. as well as the inevitable custom bit of this and that that always takes forever because they weren't accounted for in the drawings or a prior trade screwed something up (we don't do stairs, railings, or cabinetry; those are all done by other specialist tradespeople). For a large custom house, we might be there for a month.

Now multiply that by every step of the process: excavation, foundation, concrete floors, framing, exterior windows and doors, roofing, wiring, water and waste plumbing, HVAC ducting, gas plumbing, back-framing, drywall, taping, floor installation, tile work, trim, kitchen installation, stair installation, back-trim, painting, plumbing and electrical again, exterior siding and/or masonry, landscaping, connections to city services, paving, overhead garage door installation, and so on. That's a lot of people doing a lot of highly-specialised work, and structural framing is a tiny part of it.

So yeah, I'm not building my own house anytime soon. I'd sooner do a live-in renovation because those tend to be much more limited in scope. And there won't be a single breakthrough that makes building houses cheaper, because the work is by necessity highly variable and dependent on geography and local factors.


What's your interest in HN / tech?


Trying to get into web development as a career, which I really enjoy. I've been doing carpentry for my dad since high school, but I don't like it and I really don't want to be crawling around the floor all day or climbing ladders when I'm 40. I've been teaching myself in my spare time over the past few years and I recently started building a polished portfolio project that I hope potential employers will hire me on in lieu of prior work experience.


Welcome to the field! It's an exciting time to join, with a lot of messy but fun technologies to try, and different companies inventing new tools and use cases all the time.

As an aside, ever since woodshop in middle school (and one time volunteering with Habitat for Humanity), I've had so much respect for carpenters... the ability to provide an essential human need (shelter) out of trees is nothing short of amazing. And it's such artistry... there's just something deeply satisfying, almost profound, about creating works that persist beyond the computer screen. Guess the grass is always greener, huh?

Anyway, almost a bit sad to hear you're leaving the field, but totally understand your rationale. Tech is so cushy it often feels like cheating. And web dev is one of those few industries available to the average person without any special birthright or education, just a few months of training. Our society doesn't have many of those.

I hope you find a fulfilling new career soon!


Thank you. I'll always dabble a bit in construction here and there, either for myself or for friends when I can actually take my time and enjoy it, but doing it professionally is depressing because residential construction is notorious for "not my problem" tradespeople, and I absolutely cannot stand that.


Also... I have to know, lol... is this game accurate at all? https://store.steampowered.com/app/1120320/Builder_Simulator...


In my area the biggest cost is the land.


The future planned ones in Maryland look like any old Ryland home. Would you pay a premium to say you live in a 3D-Printed house?


If the future of housing is more far flung single family homes (3D printed or not), we are so royally screwed.


Interesting. I wonder how long they last. Could be good solution to address supply issues.


Hopefully I can use this to print a cheap-ish shed or small barn in 30 years.


Here’s to hoping this reduces the amount of trees we have to clear for home building and makes increasing the supply of affordable homes easier.


Concrete isn't sustainable - trees are.

The cement industry is one of the biggest producers of CO2 - trees capture CO2.

https://en.m.wikipedia.org/wiki/Environmental_impact_of_conc...

Supply issue has nothing to do with the raw materials. This is not the way.


Ok I agree on the trees.

But if 3D printing can make homes easier to build and cheaper then perhaps we can build more and help increase supply lowering housing prices.


I like the curved corners.


What is total cost on these?


They didn't disclose but I am guessing average compared to market. They're not cheap but they seem to be good quality. ps - median price of a home in Austin is $624,000


These houses will be way above the median also. Median includes a bunch of 1500sf ranches and split-levels built in the 60s and 70s.


Do they come with ethernet runs to every room? Those walls will murder RF like WiFi.


Damn. Never thought about this one. I'm sure they thought about it and have a solution but... No one likes issues with wifi...


Presumaly they put conduits in for wiring to outlets and lights, you can run ethernet or fibre with them.


It’s against code to run low voltage in the same conduit as AC wiring. There would have to be 2 separate conduits to everywhere you wanted an Ethernet jack.


Sure but if you can put one conduit in you can put two in. And is there any code against running fiber in the same conduit?


City of Austin should require a fully "paid up in advance" insurance fund to completely protect all buyers (and sellers to buyers no matter how many times in future) for the full current value of the purchase price - - against cracks in slab, walls, structural failure, etc.


You're right. The best way to make housing affordable is to require developers to pay even more money. That will make the house cheaper, and not more expensive.




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