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Why hasn't prefab construction taken over?

fastcompany.com

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Re: Why hasn't prefab construction taken over?

#91

This article seems to be missing some critical information - does this proposed system help with anything but the framing? Because framing a house, even a two story house, only takes an experienced crew a couple of days. And in the neighborhoods springing up around here, they are using pre-fab framed walls (still using wooden studs (which are cheap and plentiful), but they arrive on site as whole walls). Before frami…

One big area where modular prefab can potentially make a difference is by reducing the need for skilled tradesmen, particularly electricians, plumbers and HVAC techs. In most growing American metros, a major constraining factor on housing supply is the lack of these skilled tradesmen. In contrast, drywall, painting, and landscaping tend to be lower-skilled and easier to draw from the general labor pool. You can have…

> One big area where modular prefab can potentially make a difference is by reducing the need for skilled tradesmen, particularly electricians, plumbers and HVAC techs.

To what end? As a country we're already struggling to create enough middle-class jobs and you're suggesting we try to gut another whole sector. So that owners/executives of prefab factories can pocket the money?

If you think it's going to reduce cost or benefit the consumer, you're crazy.

I notice you downvoted without responding. I presume you've got a plan to recreate those jobs vs. just transferring wealth upwards and are keeping it a secret.

It astounds me people on HN think that eliminating jobs without any thought to the social impact is somehow a righteous goal to strive for. Yet you can't even answer what the benefit is to society other than making some really rich dude a little bit richer at the expensive of hundreds of thousands of middle class jobs. And most likely an end product for consumers that's LOWER quality.

Re: Why hasn't prefab construction taken over?

#92
post #64
post #38

Earlier quoted context omitted.

Seems like people are getting away with shoddy work then.

It costs more than it is worth to have them do better. As a framer is takes me a couple minutes more to compensate. To have the do it would take hours of labor.

I presume you're talking about scribing the bottom plate, or perhaps another board placed between the foundation and the bottom plate? Why couldn't a layer of that same sort of scribed board be placed on the foundation before placing the prefab modules?

Re: Why hasn't prefab construction taken over?

#93
post #28

I built my current house recently, and our builder used a prefab factory in the region for some of the construction. I would _never_ do it again. The process has all the pitfalls of the waterfall software development model, but at the end you have to live in the failed project! It took months for the factory to do their pre-build engineering, and that's after they started the process using plans from my architect. Th…

It sort of sounds like perhaps if you are going pre-fab you shouldn't expect to be able to do any modifications or fit their pieces to your own plans? Instead just find a site that is suitable and plop down their exact premade floorplan?

I have no evidence, but I suspect that's likely to get the best outcome, as far as the factory's quality level is concerned. They're pretty heavily optimized for a particular set of processes, and anything that departs from that happy path seems likely to increase risk.

Re: Why hasn't prefab construction taken over?

#94
post #82
post #46

Earlier quoted context omitted.

I know of at least one prefab option where permitting and inspections are streamlined at the factory.

See also "manufactured housing".

No one is writing articles asking why mobile homes haven't taken over.

In many communities, they have.

Re: Why hasn't prefab construction taken over?

#95
post #24

Earlier quoted context omitted.

While this is fine as the high-level answer, the interesting question seems to be why the as-installed cost would be the same as typical wasteful North American "stick building"? I've spent some time thinking about better ways to build houses, spoken with like-minded architects, etc., and haven't gotten to the bottom of this question. Intuitively, it seems like there should be quite a bit of room to decrease costs by…

standard stick built has a lot of things already factory done. most lumber is a standard length/width, and the entire print is built around those sizes. 2x4s come factory cut to 92 5/8 long, which (after adding the other lumber needed for a wall) leaves a finished 8 foot wall ready for 2, 4 foot wide sheets of drywall. What labor is done on site in a typical stick built construction project is mostly the same manual…

I believe the premise of many of these panelization/pre-fab companies is that manual labor is minimized within the factory through automation and also reduced on-site. There is also the waste reduction aspect. Definitely does seem that the devil is in the details on how much automation actually gets used, and to what degree the panels are finished vs. needing on-site tradeswork. Maybe in engineered production it is not far from a wash between less spent on on-site labor and waste vs. more spent on up-front engineering.

Like we often see with automation and rigor, I suppose the up-front costs really only get amortized over multiple units produced. The Blueprint Robotics company I mentioned as an example apparently now focuses on multi-unit dwellings.

Quality and repeatability, usually things that (IMO, sadly) are not highly valued in the North American market, are almost certainly improved through engineered production, but I suppose if you don't value those things, you can also keep labor costs down.

Anyway, it would be nice to see some typical and aggregate quantification of these things to really understand.

Re: Why hasn't prefab construction taken over?

#96
post #68

The article mentions labor being a huge problem. On a TV episode of Grand Designs (UK) a few years ago, the German company Huf Haus (www.huf-haus.com) sold a prefab home to a family. Their approach to labor? Ship that too. The whole crew arrived with the house components. They knew exactly how to assemble it on the concrete base the local crews had put in place. It went up ridiculously quickly, and once done, they go…

I wonder if there is a business there... get US-based crews that are capable of being prefab builds. Buy your prefab, crew shows up.

A lot of carports and similar simple metal structures are built this way. My dad ordered a shelter for his pickup camper. He already had a concrete foundation where we'd torn down a different building. The crew showed up in two pickups pulling little trailers, and they were done in a few hours.

Re: Why hasn't prefab construction taken over?

#97
post #82

Earlier quoted context omitted.

See also "manufactured housing".

No one is writing articles asking why mobile homes haven't taken over. In many communities, they have.

Locally? Because nationally manufactured home deliveries are a small fraction of what they once were in the 1970s. Adjusted for population they are down to 10% of their peak.

https://www2.census.gov/programs-surveys/mhs/tables/time-ser...

Re: Why hasn't prefab construction taken over?

#98

Used to be the lumber had to be cut from local trees on-site, and nails made by the blacksmith. Our current stick-built construction IS pre-fab by an older reckoning. I guess its a matter of how much is too far? Windows come as a unit. So do some doors. Certainly the appliances do. Nobody has to get a tinker in to make the toaster. Even so, sometimes there are hitches. I think we have to iron out the order-to-fit iss…

Exactly. Without changing buyer preferences we’re unlikely to see great leaps in optimization of the build process, because it’s already been done.

Everything in a new American home is standardized. Building a production home today is like building a Rails / Bootstrap app. 90% of the work has been done for you, you just have to assemble the pieces to suit a narrow set of choices (before you get truly custom) and this serves the needs of most buyers at a price that (outside of places toxic to new buildings) is very acceptable.

The availability of labor changes with the times. Prefab houses are like low/no-code solutions. They’re great for starting out and temporary problems, some far out last their design and that’s ok. The rest of the industry is about solving the changing tastes and needs of its customers with a standardized and VERY EASY to work with set of tools, and that’s ok too.

Nobody except Bob Villa is hanging bespoke doors.

Re: Why hasn't prefab construction taken over?

#99
post #28

I built my current house recently, and our builder used a prefab factory in the region for some of the construction. I would _never_ do it again. The process has all the pitfalls of the waterfall software development model, but at the end you have to live in the failed project! It took months for the factory to do their pre-build engineering, and that's after they started the process using plans from my architect. Th…

> […] so they don't have a strong incentive to hire skilled architects for the relatively small amount of custom work that comes in (I fell into this category). I'm led to believe that they hire draftsmen instead of architects.

If you're going to go with a vendor with a 'catalogue' of prefab plans, then I would think you'd want to choose from their pre-designed plans.

There's a middle-ground between completely prefab catalogue plans, and stuff that's built by on-site carpenters (which aren't a bad option if you're doing custom) doing 'stick built': and that's to hire a company that specifically does custom prefab frame walls:

* https://www.youtube.com/watch?v=TnnwJi40Wzo

* https://www.youtube.com/watch?v=Sl3_bo-XWGQ

Also using floor trusses to have no internal load-bearing walls and easier running of utilities:

* https://www.youtube.com/watch?v=ysT3zXkFGB8

'Completing' the build, prefab foundation walls:

* https://www.youtube.com/watch?v=6XZBkqlAnrw

Re: Why hasn't prefab construction taken over?

#100

All of the pictures are of very modern houses. I'd be fine with that, but my wife wouldn't. She prefers more of the Victorian/Queen Anne style of architecture. I wonder if there is a way they could design this system so that the innards are all the same but then you can put different shells around the innards so the home could look modern, craftsman, victorian, etc. Sort of like how you could have 10 cakes that are i…

The innards have to be different for styles from different eras unless you're really making only a token attempt at styling, because the proportions used in different eras were different.

But in the UK at least you can buy traditional styled homes in kit form from a framing/panelling manufacturer https://www.potton.co.uk/our-show-homes

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