Sunday, 27 June 2021

So, You Want to Build a House More Efficiently?

quote [ The combination of consumer tastes, low dollar value per volume building components, and the complexity of buildings inhibit efforts to scale.

Prefabbing construction is almost always more expensive than comparable site-built construction. High overhead, capital intensity, and high transportation costs eat away at cost savings. Adoption rates of new technologies are painfully slow. On-site integration can be challenging. ]

Interesting blog post about why construction is still so manual.

More here:
[SFW] [science & technology] [+5 Interesting]
[by avid@5:08pmGMT]


5th Earth said[2] @ 11:16pm GMT on 27th Jun [Score:1 Interesting]
I did see one very intriguing semi-prefab house concept that involved basically a shipping container with a self-contained CNC router scaled for 4x8 plywood sheets. The cutter makes slot-and tab pieces that hammer together into construction blocks of various sizes and shapes, which are in turn assembled into the building. ("Facit" was the name of the company)

By using cheap, commonly available material (4x8 plywood is about as common as it gets) and making the "factory" very universal and easily transportable (one machine can make any house design its programmed for), you can get a lot of the advantages of prefab construction (fast, easy, and accurate assembly from pre-designed parts) but can lose most of the transportation expense of shipping the actual prefab parts themselves. And, if adjustments are necessary or parts are damaged, they can be made on-site in real time. (in the example I saw, one of the walls was a coming out a little longer than it should have, so they just adjusted the pattern to make it shorter) Labor is still pretty cheap too--one tech to run the CNC stuff, and then just a bunch of guys with mallets and nailguns that only need to be smart enough to follow Lego directions.
avid said[1] @ 2:59am GMT on 28th Jun
C18H27NO3 said[1] @ 9:10pm GMT on 28th Jun [Score:1 Interesting]
As with other things, the industry will change when it wants to change, or stops making money. Then and only then will industry in the west change. Cheaper, Better, More Efficient will always be an outlier, and more expensive than the norm in the short run, but nobody cares about long term benefits.

Technology and concepts for cheap/ modular housing have existed forever. Industry standards are dictated by the industry, and expecting government or something else to change it is a fools errand. At least in the USA. Just remember that economic indicators in the US include housing developments and construction. Feed the industry, and "the economy is strong!!!"
the circus said @ 6:17pm GMT on 27th Jun
I had the sci-fi idea of a vertical dirigible that in addition to forming a roof over the construction site had machinery for accomplishing many of the larger or much repeated tasks of construction. Sort of think of the automated repair station from Enterprise.
zarathustra said @ 6:45pm GMT on 27th Jun
I don' know. Inevitably one of them would end up with a too many anti-vaxxers or trumpers kidnapped to form it neural net and it would go off trying to take apart Bill Gates' house.
avid said @ 8:19pm GMT on 27th Jun

25 metric tons capacity

The weight for a typical 16×80 mobile home that was built after 1980 would be around 64,000 pounds (29,029 kg).

So conceivable that you could construct houses or large sections of houses in a somewhat centralized location and then skylift them to the building site, but you'd be carrying basically a sail, so I'd bet speed and risk aren't very favorable.

If you just wanted to use it as an onsite crane, you could just drive a crane truck up.
dolemite said[1] @ 11:38pm GMT on 27th Jun
While this article raises good points about shipping density that I wouldn't have considered otherwise, I do have an issue to raise. Somebody who knows more about construction and engineering please correct me...but:

Doesn't the fact that this article only compares stick-built homes (obsolete garbage) with post and beam homes (utterly archaic garbage) make this article seem like... oh, I dunno, a steaming pile of false-dichtomizing status-quo-rationalizing dogshit? Where are the SIP and ICF options for comparison? This article is current enough to include Pex plumbing but it chooses to ignore potentially disruptive technologies like SIPs which outperform stick homes in every metric?

If I wanted to spend my entire life taking care of an increasingly sagging, squeaking, leaking, drafty, unstable bundle of sticks temporarily tacked together with up-sized pushpins, or if I was turned on by the increased risk of of mold exposure/house-fire/pest-intrusion/structural-collapse then I already know that there are multitudes of hammer-swinging semi-literates nearby willing to build me a stick house.

But I don't want those things. Ever again. My last house is gonna be SIP-based or I'm gonna build around a couple of shipping containers. Whichever way I go the house is going to rest on screw piles not a concrete foundation.

But that's just, like, my opinion, man.

P.S. If any of you are genuinely turned on by stick-built construction I wasn't trying to kink-shame anyone.
avid said @ 3:11am GMT on 28th Jun

I like those building methods in theory, but my understanding is that they are cheaper over the lifetime, not upfront. Since most houses are built for a general buyer, the constructor has little incentive.

It's a bit chicken and egg. You need qualified experienced contractors to build using these methods, but it will be difficult to find them.

Re: the article, those technologies still suffer from the same issues, except now the central factory producing them is even more centralized, that is, further away. Stick lumber is typically locally sourced. Stressed skin foam composites might need to come from 2 states over.
damnit said @ 1:46am GMT on 28th Jun
This building was built in a day using pre-fabricated materials.
10-storey residential building in China constructed in a day

It's applying technology used in cruise ships to homes and buildings. Since this was China, labor is comparatively cheap.

It doesn't scale with how we build houses/buildings in the US.
Chuckiesparkles said @ 6:39am GMT on 28th Jun
The chart with material, labor and cost cheated on the electrical. Romex is fast and cheap but it's not code in parts of the US because it's not really good practice. Rigid conduit is standard in states that don't want houses to burn down. There's some romex in my 70 year old house that I believe the previous homeowner put in.
von_sanchez said @ 8:36am GMT on 29th Jun
build nuclear batteries into every appliance and eliminate all wiring

I like this guy

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