Where has Construction Automation been successful? | Hacker News Reader

Where has Construction Automation been successful?

construction-physics.com

40 pointsltononro60 comments

I remember reading this article about Swedish home manufacturing two years ago, and immediately thought of the Hudson Valley (where I lived at the time) https://www.nytimes.com/2024/06/08/headway/how-an-american-d...

The Hudson River used to be a main manufacturing artery of the United States but has since become a relic. I still believe that region upstream of NYC could address the housing crisis plaguing the northeast of the United States. Imagine barges of housing components drifting down-river to be assembled in any coastal metro on the Atlantic coastline.

You’d need to reform the Jones Act unless you plan to build the ships too.

I live near a 3d printed neighborhood in Georgetown, TX. We would have bought one if they'd had more than 3 bedroom floorplans. They are concrete and stay cool in the summer, they also all have solar panels...

Everyone I've talked to says they are wierd looking like the movie set of Edward Scissorhands or something, but it's mainly because they didn't leave old growth trees so every tree is < 5 years old (maybe for the printer to have room to move around?) and they are very very similar. People also don't like the concrete factor.

I don't know if it counts as successful but if we'd had fewer kids I'd be in one right now!

I wonder how much of home construction efficiency improvements are held back by taste for traditional appearance vs. other cost/performance characteristics.

The difference in styles between residential and commercial construction is probably an example of this. Not many commercial buildings with tar paper shingled roofs.

The only reason I can think of that houses don’t usually have metal roofs is because they cost at least double, if not triple. I have seen homeowners use metal roofs, but it’s one of the first cost reductions because a good shingle roof is already good for 30+ years.

For a business, it can make more sense as it might be a more long term structure, plus it would contain more valuable items (or at least cause more loss if business is interrupted).

> The only reason I can think of that houses don’t usually have metal roofs is because they cost at least double, if not triple

Also noise, if you live somewhere with a lot of rain.

I wonder if the longevity argument really holds, too. Anecdotally, our local public housing project invested in metal roofs many years ago (less than 30, however) but a good fraction of them have been replaced since with contemporary asphalt shingles. I do not know why they failed, but the switch back to asphalt says something.

To me it says that someone in the housing authority fell for a sales pitch on metal roofs. "Buy it once and never have to pay for a roof again." That person is now probably long gone, as is the salesman and likely the roofing contractor who installed it. The roof is now leaking, and the current administration looked at what they could afford and asphalt it is.

I agree. The sales pitch on metal roofs is that they last twice as long as shingles, but the reality has not matched that promise. If I were replacing a leaking metal roof that cost me twice what a shingle roof would have cost, and it has been less than 30 years, I would be a fool to buy another metal roof to replace it.

> That person is now probably long gone, as is the salesman and likely the roofing contractor who installed it.

AKA "I'll be gone. You'll be gone."

https://en.wiktionary.org/wiki/IBG_YBG

I didn't mean to imply that there was some kind of collusion going on, but that sort of thing certainly happens too.

Metal roofs for SFHs are mostly beneficial in wildland / forest areas where there are wildfires. Shingles will burn (they're made of petroleum products), while a metal roof will resist far far far longer. However this only makes sense if the rest of the structure is also just as fire resistant.

Metal roofs will also last a lot longer. Their color may not, but the roof itself, as long as it was installed properly (major component here), will outlast asphalt by decades.

FWIW a bunch of friends of ours live in a development with metal roofs (built late 1970s) and they said it's been great. It just works, no leaks, no repairs necessary.

There's probably a bit of selection bias in both directions: metal roofs that don't work get replaced with shingles and are no longer metal roofs, while metal roofs that do work have owners that don't think about them much and don't complain about them.

> Not many commercial buildings with tar paper shingled roofs

I mean, this is kind of true and kind of untrue. There aren't a lot of commercial roofs with literal residential asphalt shingles, but many commercial roofs are things like mod bit which are practically the same concept, just a mod bit needs to handle an extremely low to flat pitch while residential shingles assume a decent pitch to the roof. Tons are also just single-ply membranes, which often don't even last as long as a good residential asphalt shingle install.

Its not like every commercial building has a metal roof. Just look at this random commercial/industrial office park:

https://maps.app.goo.gl/7X1NUTwrTUdH21o1A

Take a look around. You see a lot of metal roofs, yes. You also see membrane roofs. You see mod bit. And you'll even see some old built-up roofs.

They made a new office building a number of years ago that I had the pleasure of watching it go up. At first it was all grey concrete that they poured, but then, they hung, like giant paintings, a brick facade on the exterior and the columns. If you hadn't seen it go up, you'd think it was a brick building. I'm sure it cost extra, but looks don't have to go out the window in the name of efficiency.

> Construction is famously labor intensive: direct labor makes up close to 50% of the cost of constructing a new single-family home in the US, compared to around 6 to 8% of the cost of manufacturing a car.

Is this only calculating last mile labor, or all the labor along the way? Like, for a car, does it count the cost of steel as purely non-labor costs, or do they factor in the labor cost for mining the ore, etc?

Because I feel like at the end of the day, almost all costs are 'labor' costs, they are just paid by different people/companies earlier in the process. Housing just has a lot of the labor as the final step, assembling the house on site. Cars have more of their labor at earlier stages of the process, and the assembling is mostly automated.

As I understand it, even just considering ‘last mile’ costs, labour is a majority of the cost, and fit-out is the majority of the labour. Then again, where I live skilled trades cost a lot, so this is probably different elsewhere.

The big changes I've seen over my lifetime have been tooling and materials. I remember when framers did everything with a hammer, a circular saw, and a speed-square. Now we have nail guns and cordless impact drivers and miter saws. Fiberglass batt insulation is still a thing, but now there's also urethane spray foam. We have engineered beams and OSB sheathing pre-coated with a moisture barrier. There's a lot of things that all add up to better performance and less manual labor.

My idea is you mass produce a housing core. A large unit with dividers but is a single big object consisting of a toilet, shower, kitchen sink, electric induction kitchen stove, dishwasher, heating/air-conditioning heat pump, and a living room wall with a TV. "Just" one giant unit to plop down as the central core of a living space, and then everything else can go up around it.

Sounds like a desktop machine with a few USB ports. You could probably sell this architecture to today's home buyers, especially those who have been lionizing the Sears mid-century "homekits". Many of those homes looked "cookie-cutter" when they were assembled, but small alterations to facade, adaptations to account for terrain, and a few customer preferences led to cozy neighborhoods. Too bad HOAs became drunk on power.

People love the promise of renovation and "growing with the home". When my wife and I bought earlier this year, I was enthusiastic about one underutilized wall on the mudroom; I could already imagine a "bump-out" that becomes an in-law suite.

It's kinda ridiculous that we still build walls brick by brick, on site, instead of just building most of the house elsewhere and only assemble at the site.

If you're interested in the topic, the author writes extensively on manufactured homes.

Why is this ridiculous?

do you build a car from raw materials and casting every component in the same shop?

You could use the metaphor of sealed units in modern cars that can't be repaired.

And houses are expected to last longer than cars.

I'm not saying you're wrong person se, but I disagree with the analogy

Are there really many parallels between a car and a house? The car is considerably more complex with dramatically less variation between builds. It is not like homes are constructed from raw materials, either, lots of the pieces are built in a factory and then brought on site to be connected.

There are enough to make meaningful comparisons vs, say, manufacturing a laptop. They're both too big to carry, and expensive enough that most people aren't able to afford more than a handful in their lives, and may possibly even just only rent one. So cars and houses are more similar in size then cellphones or a meal at a restaurant.

Ever try putting a brick wall on a truck?

Difficult with brick walls, but easy with concrete walls. The Soviet Union famously did that a lot. For the brick aesthetic, just add a brick facade on top. Or insulation foam boards and plaster for a more boring but functional look

They did this a bit in Britain post war.

It wasn't and isn't particularly popular. I don't know the precise reasons, but I suppose the fact it was tried, and didn't work says something.

At least in the UK, a lot new development is done like this. In London there's massive amounts of new housing in the New London Vernacular style that uses brick cladding panels, either real bricks or thin "brick slip" that are fabricated off site: https://en.wikipedia.org/wiki/New_London_Vernacular

sounds like a problem engineering can't solve? Stop using bricks is an idea.

> Stop using bricks is an idea

I would guess that happened a long time ago and the vast, vast majority of what looks like brick houses today are facades. Does anyone want a real brick house these days?

Theres less efficiency here than would be thought. Building codes, technologies, materials, styles, needs etc vary a lot by location.

Manufactured homes are a thing. You can literally buy one for 100k-300k

We call them prefabs i.e. prefabricated.

Has anyone made multi-story manufactured homes?

Most homes in my area have two (3 with basement), traditional single story ranch doesn’t make good use of the limited land. So if multiple floors aren’t available they’re not an option for a great many homes.

It’s kind of amazing we’ve perfected the subdivision. Building and rebuilding the same 3 floor plans a hundred times over by hand. It’s automated in a way and yet not automated at all.

It's done in Japan. There's a video of the process here. https://www.youtube.com/watch?v=rhDG__-UVaQ

There are but those companies often go out of business quickly because American manufactured home installers suck. In the US manufactured homes are sold by the installer. They do a bank contract with a customer. The escrow process releases funds to either the installer or the actual factory. The factories can definitely produce sections with multiple stories, etc.. but then the installer is then responsible to have crane support and expertise in more complex "marriage lines" than the typical "double or triple wide" single story home.

Once you get into this territory, at least in the US, it makes more economical sense to have a builder create a 2/3 story home.

Eh? Such houses are now common, at least here in Europe. I live in one! Entire walls were manufactured in factory, then brought on site and assembled. But the house is not from bricks, the structural material is wood and oriented strand boards (OSB).

I think the Problem is transportation of larger Units, different buildung Codes from region to region and induvidual requestt

IIRC the cost of a stick built home is only ~15% higher than an equivalent manufactured home, but by building on site you have more flexibility for custom layouts and other choices which fit the local environment better. A modern home builder typically has a set of plans to mix and match and their build process is really dialed in -- eeking out a bit more efficiency by doing it in a factory is offset by the cost of getting the completed product on site. Plus a good chunk of the cost in a home is site prep anyway.

Also, at least in my area, the trend seems to be towards smaller lots and two story homes. There might be modular homes that could fit that niche, but currently manufactured homes are just big single story rectangles.

turns out that's not much cheaper and really limits design choices and sometimes house locations

The most obvious reason for that is transport. The main components of houses tend to be much bigger than what fits on the back of a lorry.

You could flat pack them like IKEA furniture to make them fit on the back of a lorry. Take the walls and floor and ceiling/roof apart, and slot them vertically, and then assemble them into a building on site.

Sears did this over a hundred years ago, except in a rail car instead of a truck trailer. You can buy kit homes and outbuildings from Menards and other places.

The other issue with manufactured homes, aside from the logistics and local codes, is financing. Loans are harder to obtain and are more expensive than onsite construction.

It doesn’t cost that much more to frame up a house in the field vs framing it in a warehouse.

3D printing of concrete homes ?

Interesting, but currently more of a novelty.

I wouldn't put that in the "success" category just yet

Even more labor-intensive, actually. Needs significant babysitting for things like electrical fixtures and window opening, and the final wall is a maintenance nightmare if it isn't plastered smooth.

Only because we culturally expect recessed wiring and plumbing. if we went back to knob and stick wiring and external plumbing, 3d printed homes are much easier to make.

Lego bricking with ICF is probably as best as it gets right now.

It's really not any easier at all, and really not a wide labor market for it... and an ICF house still needs framers.

It's a really expensive and laboruius way to increase the R value of your home basically.

I'll bet fire resistance and temperature stability are all good though.

Don't know about noise - wonder if it is better or worse?

You still have to solve all the MEPs so where does that go in your process?

What does MEPs mean in that context?

Mechanical, electrical, and plumbing

They don't. They come in later and do their thing as normal.

MEP workers have huge regulatory moats and trade groups with war chests which is why their bit of the process isn't being discussed here. If the tech isn't at a point where it can beat the relatively "exposed to the free market" framers and brick layers then there's no way it can fight the MEPs who have the laws and rules and codes they can leverage.

I'm saying they can't take shortcuts like prefabbing walls without the stuff that goes in walls in them or at lesst coordinated sleeved etc

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