[brudgers]

3D printing doesn't relieve any important construction constraints and probably raises costs because unfamiliarity increases risks and increased risk increases price.

Superstructure is about the easiest and fastest part of residential construction. Sitework, finishes, and MEP systems are harder, tend to take longer, and cost more.

Anyway, market rate housing sells at market rates no matter how it is built.

[pxmpxm]

>Superstructure is about the easiest and fastest part of residential construction.

I'm perpetually confused on that front - interior, especially drywall, is stupid labor and time intensive (have to wait for taped joints to dry). There should be huge econmomies of scale for prefab walls with electric and ducting built in, yet all we see is this sort of 3d printing stuff.

[brudgers]

How do you finish the joints between sections of prefabricated walls?

Where do you store hundreds of running feet of prefabricated wall during construction delays?

How do you move sections of prefabricated wall into and within a dryed-in building?

How do you trim a section to fit and extend another when construction is not ideal?

Who is responsible when something is not right?

And of course there’s getting UL listings for any proprietary electrical connections and issues of inspection for code compliance.

Prefabricated walls are common and are suitable for cubical farms. They tend to cost more psf than regular construction but can be depreciated as furniture and reconfigured more easily than site built walls and fixtures.

[lowbloodsugar]

I feel like you’re telling ford how the Model T production line can’t work because someone wants a different color.

Yet, it’s ironic that we still end up with cookie cutter houses, but they are all built as if they are bespoke.

[brudgers]

You cannot build an airplane out of bricks.

[ben_w]

I don't understand the metaphor and how it would apply to this.

(But also, this feels like a Mythbusters episode challenge, and they managed to get a lead balloon flying).

[brudgers]

Yet successful balloon building businesses don’t build balloons from lead because of the fundamental nature of the balloon building problem.

[wycx]

https://en.wikipedia.org/wiki/Huf_Haus Construction of a Huf Haus in the UK featured in the 2004 series of Grand Designs.

[pxmpxm]

Those are awesome, does anyone export this to the states? We just got a prefab studio from Schildr that's manufactured in Turkey and disassembles into a sea container. I imagine something similar would work for Huff houses?

https://schildr.com/en/@schildrusa

[wombatpm]

Standardized wall sections, JIT inventory management, dedicated install teams?

[brudgers]

We have standardized components delivered just in time by ordinary vendors and installed by subcontractors specializing in that work.

It is all commoditized and builders and trades people have choices about who they work with and long standing business relationships.

The inherent complexity of construction is a job shop scheduling problem which is not just in NP it is NP hard.

With a whole additional dimension of human social relationships and woven in. Everyone is trying to solve their own NP hard problem across a different set of projects and under a different set of constraints.

[dhosek]

My parents’ home, built in the 1950s was built from pre-fabricated components. From what my dad says (his mother was the original owner of the home), the fit of walls was very poor and they had to do a lot of patching to fill in gaps between the walls and the ceilings. There have been numerous attempts at prefabricated building but all have failed to gain any traction.

[teruakohatu]

A lot of homes in New Zealand were sent over 150 years ago from Australia and Europe as prefabricated kits. Apart from the abysmal lack of insulation, they are still going strong.

Right now most new houses have the wood framing CNC manufactured based on plans, shipped to the building site and assembled, then modified as needed by the builder.

Our roofs are almost exclusively steel, which are also CNC cut and shipped to the site and installed by roofers.

[throwaway173738]

Some Quadrant homes in Washington are built this way. The framing is done in a factory on a gantry and the walls are trucked out and assembled on site. There are subdivisions of thousands of houses built this way.

[bilsbie]

You’re not wrong. That is confusing.

I think of it like the satellite industry. Crazy high launch costs and weight penalties make satellites expensive to build. Maybe there’s some rule that the cost of the satellite has to equal to the launch cost?

I think the same things happens to building prices when the land cost and available land is super limited. Construction kind of rises to take a piece of that?

I’m not sure if I’m explaining the idea well.

[toast0]

I think you would end up with a lot of onsite finish work with prefabbed walls that won't end up saving much time. And it makes transportation a lot more difficult.

That said, searching for prefab walls brings up a lot of things, from whole wall panels, to just prefabed wall framing, and of course, prefabed whole houses. So, it's out there, it's probably a matter of what a builder is familiar with and what's cost efficient for a particular job.

[explorigin]

SIP walls are basically this. It's a foam-core panel board with chases built in for electrical.

[bluGill]

Houses are mostly prefad - everthing is a standard dimension before it arrives on site.

[CalRobert]

You can, a random example of someone doing this is https://prefabhome.eu/en

[jqpabc123]

Anyway, market rate housing sells at market rates no matter how it is built.

This is a demonstration project.

If there were any economic advantage, I would expect them to be eager to demonstrate it.

But such does not appear to be the case. $450-600K for a simple, single story ranch 30 miles outside of Austin is not exactly awe inspiring.

[Dig1t]

Many of these printed homes just leave the concrete exposed inside the home. They can just be painted directly, and they are also well insulated already so you don’t need to fill the wall with insulation.

So not only are you framing differently but you can skip the drywall and insulation steps of construction as well. This is the type of finish work you are talking about I think.

[brudgers]

You still have to mobilize a drywall crew for ceilings. And your painter needs to use another primer and paint system for the concrete. Hanging interior doors and trimming them out is no longer a job for nails. Same for crown and base moldings and kitchen cabinets.

And you still have to insulate. Four feet of concrete wall thickness is needed for a nominal R10.

[liontwist]

> market rate housing sells at market rates no matter how it is built.

This is true. Do you see any opportunity for efficiencies in rebuilds?

[aleph_minus_one]

> This is true. Do you see any opportunity for efficiencies in rebuilds?

When this technology has become much more established, the "risk premium" can be decreased by a lot. Then one can start to find methods to make the process more economic. And I see quite some potential there, because 3D printing can potentially be done in a much more "automatic" way than other existing house building processes.

[brudgers]

What do you mean by “efficiencies?”

[liontwist]

Like you mentioned the market for housing is more about where people want to live, and the actual building on it is less important (up to first order quality and space), so that optimizing construction costs doesn’t really save money on housing.

But suppose we have a country of aging housing. Could prefabrication techniques result in lower costs when replacing existing buildings without a land transfer?

[brudgers]

1. In successful businesses, lower costs usually correlate to greater profits not lower prices. This is particularly the case with the narrow section of the real-estate market that is single family housing (single family housing is about the lowest and worst use of real-estate (i.e. the opposite of highest and best use)).

2. Single family home construction in the US is highly prefabricated. You can go into any Home Depot and get lumber, fasteners, fixtures, appliances, and anything else you need to build a house. All of it movable and installable without much mechanization beyond a truck (and Home Depot will rent you one of those).

3. Tearing down existing houses for replacement only makes economic sense in two cases. The first is when the value of the land justifies more expensive construction (e.g. MacMansions). The second is when redevelopment is not for the market (e.g. Habitat for Humanity).

4. It is a mistake to look at construction as inefficient. Construction is just one component of real-estate markets.

5. We have very efficient prefabricated housing. It tends to look like mobile homes.

6. Wealth preservation is the primary function of the real-estate industry. Buying and selling for profit is the low end. The real money in real-estate resides in income producing property not single family houses.

[eightysixfour]

> 3. Tearing down existing houses for replacement only makes economic sense in two cases. The first is when the value of the land justifies more expensive construction (e.g. MacMansions). The second is when redevelopment is not for the market (e.g. Habitat for Humanity).

Interesting you chose “MacMansions” as the example instead of increased density. In my (very) urban area they tear down single family homes and replace them with 6-9 town homes.

[brudgers]

I chose MacMansions because it was clear and ordinary and uncomplicated.

Building a six pack is driven by the same basic economic condition, the existing building is economically obsolescent.

[cbames89]

It's ~21% the cost of a home, it's actually the single most costly and labor intense category. That being said it does only take 14-21 days to frame a home.

[brudgers]

At scale it takes significantly less time because the designs are familiar and there are not mobilizations and demobilizations. The next framing job is on the next lot.

[janalsncm]

So if a technology could cut that cost in half it would be desirable even if it took twice as long because in real terms your final cost drops 10% and only takes 2 more weeks.

[brudgers]

It would depend on what else was in the spreadsheet.