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Comment by ibisum | Hacker News Reader

Prefab is labor and gas intensive. The advantage to this technology is that you can do all the assembly in place and don't need trucking and all the other headaches to get stuff there. As a tool for building dwellings in remote places, I think this tech has a bright future .. I can see it being used to rapidly build refugee homes in deserts and so on..

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I worked for a construction company once, and spending some time on site while buildings are going up makes a couple of things very clear:

Walls are easy, cheap, and extremely fast to build.

Almost all the effort in construction goes into putting the fittings into the rooms.

There are interesting things you could do with 3d-printed concrete, like creating complex structures on-spec, but labour-saving just isn't going to be one of them - the labour costs of brick walls are minimal. It's the plumbing and electrics that get you every time.

I don't see a problem with printing plumbing. Just switch from concrete to PVC for the tubes.

Electric wires might be a bit tricky to "print". But I can imagine a machine that inserts the wires into the right places...

One day, you'll print a house with curtains and wooden floor included.

If you could build a 3d printer that could lay down PVC pipes to heating/hot-water spec, that would revolutionise construction in the way that a concrete printer seems unlikely to do.

If you could do walls/floors/plumbing/electrics in one machine in one pass, it would change the world in ways that are hard to imagine - this would completely change the economics of construction projects.

Nobody's done those yet, sadly. They seem difficult things to design.

Yet is the key word.

While it might be possible to print PVC pipes that are waterproof at the same level of reliability as traditionally manufactured ones, this seems rather overly optimistic. Bringing in pre-made pipes will probably be required for quite some time, before the printing technology is reliable enough for that.

I work in construction.

The issues I'm seeing are: no insulation, no interior framing for drywall and vapour barrier, no exterior framing for sheathing, insulation, building wrap or siding material. No plumbing, gas lines, wiring or ductwork.

The best this does is create an external shell that's still going to require a lot of processing to make it a commercially viable product. Minimum you would need to install a rigid foam, to apply a stucco coating, with construction adhesive just to be able to make it attractive as a home.

You can't even build a house from the foundation up with this. There's weeping tile and underfloor drainage that needs installing. There's water barrier that needs to go on the basement, there's damp coursing that needs to go on to prevent moisture travelling up the structure (rising damp) and there's adequate venting that needs to be installed in any masonry or concrete wall to ensure proper breathability so it doesn't rapidly deteriorate and cause damp in the insulation or rotting/rusting of the interior studs.

This is cool sure, but without the machine being able to install PVC and PEX piping for plumbing and conduits to run the electrical after, you're going to be waiting on humans to do all the work still and you might as well have two crews working rather than have a machine just idiling waiting for the meat sacks to be done.

A well coordinated house project goes very quickly. The issue is most projects are subcontracted and its waiting on a contractor to be available.

I recently had a fantasy of building my own house, so I did my research and realized that meeting the code and housing bar is fairly difficult.

So... I bought a house to learn other skills.

This project is a fantastic proof of concept. The problems you listed could be solved with appropriate planning.

The open question is whether or not this has a market. If the cost is right, then this could be a great toy for children... or even in parks. Or just large scale art.

My dream is to buy 50 acres of land and build my own house.

I'm starting my own company, so hopefully in over a decade I'll have it to a point I can take a hiatus to build my own house. I figure I can draft my son like my dad did when I was a teen (renovated a 1600s French farm house).

You can use insulated concrete forms[1] blocks. I've helped a friend build a house this way, it's like putting together lego blocks.

[1] https://en.wikipedia.org/wiki/Insulating_concrete_form

You'd still need to move around the input materials to the printer. I fail to see how it would be less gas intensive.

I agree about labor though.

One advantage might be that you could have all the materials delivered in one go from a single supplier (a concrete manufacturer), instead of having multiple deliveries from different places for the different materials (brick, concrete, cement, rebar, etc).

Prefab houses already largely solve this problem.

All materials are delivered to the prefab factory, in bulk, the prefab house is assembled complete in about a week (including internal finish), and the house is delivered in a single delivery.

If you locate your prefab factories along convenient bulk shipping routes (railroads, rivers, canals) and order houses from the closest factory, you've reduced your shipping costs considerably.

the problem is that prefab houses are not very hurricane / tornado proof. A good cement printed house could be made to withstand a lot better conditions. I think this is something very important for the future.

I do really like this idea. I believe something like this, with some prefab parts that are automatically mounted could really get us one step closer to something like what Jacque Fresco envisioned http://en.wikipedia.org/wiki/Jacque_Fresco. I especially like his automated building tech which could combine prefab with foundations etc being built by a machine like this. http://thevenusproject.com/technology/construction

There are shoddy prefab homes and good prefab homes and shoddy custom builds and good custom builds.

This manufacturer says No Manufactured Home built to the new Florida Building Codes implemented in 1999 went down in any of the hurricanes of 2004-2005.

http://www.leecorpinc.com/leecorp-faqs.htm#9

That's just the first interesting link I found searching on "hurricane double wide", and of course it is promotional, but what is important is whether the building is built to stand up to the storm.

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