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:
While architects can be talented and make a great design on so many levels, can they really fully optimize space for usability and features to a deep level? I just think of RV interior design, which amazes me sometimes with the ingenious use of space that is clearly the result of dozens of rounds of iterative design over the year.
Not that a house should be that crazy (aside from the tiny house movement) with maximizing space, but if there were industrial production, then you could get to deep optimization of the floor design.
What always strikes me with (american suburban) houses, is that they are very inefficient at vertical storage of things like clothes, dishes, and a ton of other housewares that you need on a daily basis (so you don't dump them in the basement). I walk through 3000 and 4000 sqft houses and they are only marginally better than a well designed 2000 sqft house in usability.
1. Be stupidly rich and don't give a crap about how much you spend
2. Do damn near all of it yourself.
There are examples of "leases of years" like Canberra/ACT in Australia, where all titles are for 99 year leaseholds.
They've started renewing them since the first leases were granted in the 1920s.
the 99/100 year lease is quite common in many Europan countries. It's not "exceptional" here
And actually you bring up another wrinkle, which is if you don't own the land underneath, there are plenty of lenders who also won't lend to you to buy a manufactured home, because they consider it to be personal property rather than a permanent dwelling (which they could more easily foreclose and sell)
I have to admit that having a prefab building that has one side a foot longer than the other side not sound like a condemnation of the concept but the factory that built it. I presume one would have recourse under contract for such a foul up?
Possibly, but delays in construction are what kill you. You can't really FedEx overnight new structural steel framing components, so now you're blocked until they can get
a. rebuilt, and
b. freighted out to you
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.
I have been to a Bone Structure presentation. They fabricate all parts and interfaces using computer operated cutters with extreme precision from CAD plans. Note that parts are made of metal, not wood.
The structure is then aligns perfectly and all connection holes align perfectly as well.
The building is then assembled using just an electric screw driver, on sight. They claimed that almost anyone could do it, like IKEA. But they still require skilled technicians. But the point was that it isn’t a rocket science and plans are designed in such a way that you can’t really mess it up too much.
I've worked in traditional construction and the plans are never accurate with hundreds of omissions/errors/interferences. Those can be corrected in real time when something is field built, but are nearly impossible when the house ships wrong but nearly finished.
I can see it working with cookie cutter housing - first ~5 will be garbage as they find bugs then slap a thousand identical copies up cheaply. For custom it's a mess.
The buildings also look horrendous by default, artificial and cheap looking with a complete lack of character. I’m all for prefab in theory but it’s like building a whole piece of software without testing any of the interfaces fit together or that say logging and error handling are plumbed in without testing them. It’s clearly a recipe for disaster even with the best organised prefabricator.
We were very aware that big projects, be they software or home construction, don't ever go perfectly, so we made a conscious effort to stay calm and solution-oriented through the entire multi-year process. We came in very slightly under budget, and things that need to get addressed are getting addressed, whereas a lawsuit would have turned things adversarial very quickly.
Most large projects have some central features/processes that are by their very nature both very expensive and very complicated.
The entire prefab industry is built around minimising those things - but then something ELSE becomes the most expensive/complicated thing. You then have a situation where if you're seen as a bottleneck, holding up the expensive/complicated thing, then the total cost of the project will balloon.
Many prefab companies know this and are happy to sell modules with little QA work done, because it's unlikely that there will be serious repercussions. Once you accept the work then it'll be too hard for your legal team to fight for (or at least, not financially worth it).
I'm not saying that prefab companies are ethically bankrupt, but it IS an environment that promotes this method of doing business. I've been in construction for mining/oil&gas companies, on both sides of this situation, quite a few times. The amount of shoddy work you're willing to accept is quite terrifying once the cost for re-work gets into nine and ten digits.
The one I remember had to do w/ $1900 worth of lost wedding photos cuz a server died or got deleted. Cost more to twist the knife in court than to just settle.
Doubly so if it came after all the stress of custom-building a home. My blood pressure is worth more than that.
Oh and the 15k are only for legal costs. Don't forget rent for 3 years on top of that. And all the money that you'll still have to pay for the construction. And stress (medical bills are not cheap).
The overwhelming downside of not needing professional builders to build a house is not having professional builders build a house. Half-assed amateurs aren't going to give you the quality you expect for your home.
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. The companies building these modules tend to sell mostly from their own catalog of floorplans and modules, 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.
They built one of the modules a foot too long, so it hangs over the edge of the foundation. They also messed up the roof line, so some guttering and geometry had to be changed for the garage that was stick-built onsite. They did all of the drywall wraps around the windows incorrectly. Every single door was hung incorrectly, some with chunks taken out from bad routing. The vinyl plank flooring has bubbles because they didn't float it correctly. They omitted electrical features that were on their own drawings. They ordered a few wrong windows, so they charged me anyway and just laid them on the floor when they shipped the module.
It'll all be fine at the end of the day, but the parts that were built onsite are all so much better. No cheaper, mind you, but faster and with much less drama. Maybe there are some parts of the industry that do a lot better, but I kind of wish I'd listened to my dad when he said "the pioneers take the arrows".