Why hasn't prefab construction taken over? • Hacker News Board

Re: Why hasn't prefab construction taken over?

#101

Post by aidenn0 » Mon, Oct 12, 2020, 9:35 PM UTC

bluGill wrote: post #32

sjg007 wrote: post #18

Earlier quoted context omitted.

Huh? There's a shortage of carpenters so if you can go prefab it is a win. In fact the article shows that if you can build a house faster with prefab at the same cost as a traditional house that's a win.

There isn't a shortage of carpenters. There is a shortage willing to work for the wages offered. I've done carpentry work in the past, offer enough money and I'll leave my tech job. I'm not the only one who could do carpentry for the right price.

Any skilled job that can be done poorly with little training becomes a bit of a lemon market.

I hate painting. I'm also a terrible painter. However, I've given up on ever hiring painters. Every professional painter I've used has either prepped the surface improperly, or put the coats on too thick, to the point where I rub paint off if I brush up against the wall.

I'm willing to pay more for better work, but I can't easily tell who will do a better job.

Re: Why hasn't prefab construction taken over?

#102

Post by person8645 » Mon, Oct 12, 2020, 9:36 PM UTC

irrational wrote: post #60

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…

Architect here. This gets much more difficult if you dive into the deeper problems that architecture attempts to address. Victorian/Queen Anne homes are based around smaller, more numerous, and more specific rooms. The exterior appearance flows from the way that people lived in that time, with the HVAC and construction materials and methods available to them. Ornate hand detailing on the high-quality surviving examples looks right because of the scale and use of the spaces within, as well as the market of hand carpenters. Applying a kit of modern materials to diverse spatial problems won't really yield good designs.

There's a reason that modern architecture developed around the international style when concrete, steel, glass, and mechanical HVAC all developed and became cost effective at the same time as open-floor plan living and the decreasing number of household staff. All of these factors go hand in hand and a robust solution would have to touch on these deeper considerations. Not to say it's impossible, but trying to put out there that architectural design is more than skin deep.

To use your analogy, you can use React to build what used to be a mid-90s static styled HTML site, but you probably wouldn't.

Re: Why hasn't prefab construction taken over?

#103

Post by seibelj » Mon, Oct 12, 2020, 9:46 PM UTC

tw04 wrote: post #91

dcolkitt wrote: post #63

Earlier quoted context omitted.

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…

This is the fallacy - The Fallacy - that is always made by those who don’t understand economics.

Why did we build the car when it put all of the horse tradesmen out of business? Why do we use elevator buttons and put the doormen out of a job? Why did we create the Internet when perfectly good newspaper printers could pass information to us?

You are making an age-old argument that we need to reduce productivity in order to save jobs. If you spent your whole life scrubbing a floor with a tooth brush when right next to you is a mop, just so you can ensure more of your time was spent washing, wouldn’t you feel like your life was wasted?

Re: Why hasn't prefab construction taken over?

#104

Post by throw0101a » Mon, Oct 12, 2020, 9:49 PM UTC

tw04 wrote: post #91

dcolkitt wrote: post #63

Earlier quoted context omitted.

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…

>> 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?

To the end that you can get your house built on a schedule that you want. A neighbour is a general contractor who has a good reputation: he, and the specialty teams he uses, are booked at least a year out.

This isn't too say we shouldn't train more skilled trades, but having a spectrum of of people available helps those you can't afford to pay top dollar for top talent to also get quality results.

It should also be noted that not everyone is gifted enough to be a top or even decent trade, yet we want as many people as possible to be productively employed. There will some percentage of the population that may be most productive simply following what the computer tells them to do:

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

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

Re: Why hasn't prefab construction taken over?

#105

Post by brixon » Mon, Oct 12, 2020, 9:49 PM UTC

istorical wrote: post #87

pfhorge wrote: 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?

It sounds like they were trying to build a Buick on the Ford Model T assembly line.

Re: Why hasn't prefab construction taken over?

#106

Post by jnwatson » Mon, Oct 12, 2020, 9:52 PM UTC

pfhorge wrote: 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…

A coworker had a similar story with his prefab.

After it was delivered (and it comes delivered with sheetrock walls, electrical, and subfloor), my coworker noticed that the the factory forgot a step: the plumbing. The builder had to rip out lots of the sheetrock and install plumbing.

Lots of mistakes occur while building a house. The difference is that when the workers are already in the field, it is generally quite inexpensive to identify and fix any problems. Not so for the prefab stuff.

Re: Why hasn't prefab construction taken over?

#107

Post by notahacker » Mon, Oct 12, 2020, 9:55 PM UTC

falcolas wrote: post #16

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…

Beyond walls, there's entire rooms, provided your client wants a lot of identical factory-finished rooms small enough to transport. Doesn't really work for your average private housing client who wants big open plan areas to add their own decoration to, but it's ideal for chain hotels and student/social apartments. That's where the construction speedup is more noticeable because the unit fitouts can take place in parallel to site prep and foundation works, and where you also get economies of scale and better QA from fitting lots of copies of the same bathroom on a production line.

Re: Why hasn't prefab construction taken over?

#108

Post by usrusr » Mon, Oct 12, 2020, 9:56 PM UTC

Location location location. When a large fraction of total cost is for the plot, major savings in the construction process aren't very appealing. Particularly when it's on a mortgage and the numbers are an order of magnitude beyond all other purchases with our without the construction compromise.

Re: Why hasn't prefab construction taken over?

#109

Post by hansvm » Mon, Oct 12, 2020, 9:57 PM UTC

jeffbee wrote: post #4

Prefab is the wrong optimization. It targets a minor improvement in a small part of the overall budget. Most of the time and money of construction in America is tied up in land prices, permitting, and regulation. Prefab solves zero of these issues. There is a building going up in Oakland right now where Factory_OS put out a press release that they had built it in ten days. But they spent 7 years getting approvals, 18…

That depends heavily on where you're building. There are plenty of places you can pick up a few acres for $10-$20k (with electric/water access) and have a minimal permitting process that's over in at most on the order of weeks.

Re: Why hasn't prefab construction taken over?

#110

Post by throw0101a » Mon, Oct 12, 2020, 9:58 PM UTC

redfalcon6 wrote: post #49

pkaye wrote: post #10

I found this prefab house approach shown on This Old House feels much better. Still made of wood but made in modular pieces in the factory that can be quickly installed in the field. https://www.youtube.com/watch?v=jqXmNeT1uKs

I have one of these houses. Just built it and moved in. Save time and increase quality. Dried in with insulated walls / windows in 4 days! Price is still an issue. Part of the reason is that we pay no penalty for crappy energy hog homes. You can build with prefab panels and get airtight really quickly. So all the extra $$$ goes into better build and overhead for the factory.

> Part of the reason is that we pay no penalty for crappy energy hog homes.

You pay higher heating and cooling costs over the lifetime of the building. It's just the penalty is a 'death of a thousand cuts' that may be less noticeable than a proverbial broadsword to the face of paying for some extra insulation and proper house wrap upfront.

Just improving airtightness and mandating blower door tests in building codes would probably go a long way towards more efficient homes. Once you're more airtight you then of course have to ventilate right: HRV/ERV for refreshing of the air and stand alone dehumidification units.