[londons_explore]

> The construction industry ... manufactures products that are too big to fit in highway lanes.

This is why I believe the future of construction is portable 3d printing. Imagine a 3D printer which fits on a truck, yet can be assembled in an hour and can print something the size of a large house from fiber-embedded cement. The printer would have nozzles for paint, foam, tar, electrical wire and PET plastic. It would also have a scoop to remove soil.

A team would drive the truck to the worksite, assemble the printer, start it going, and come back in 2-3 days when it was done. The printer would dig foundations, lay a fiber-cement foundation, damp proofing tar layer, build double skinned walls with foam between, paint the inside and out, install wiring and pipes, and build a foam, cement and tar roof. The house would have premade cupboards, bathtub, washbasin, etc.

Humans would come back to fit carpets, electrical outlets+fusebox, appliances, windows, vacuum formed liners in the bath/washbasins, etc.

[vlozko]

> The printer would dig foundations

You lost me there. I’m guessing you’ve never had to deal with rocky New England soil and non-flat grades. I’m sure many other regions have their own challenges, such as water tables and custom insulation requirements.

[londons_explore]

> rocky New England soil

Even a tiny creature like an ant can dig holes in tough soil. A machine can too as long as it has feedback (ie. it can see the rocks and keep digging around and bashing till it comes lose.)

> non-flat grades

Well you dig it till it is the same shape as the plan...

> water tables

Either lay the concrete underwater (most concrete can be laid underwater) or dewater with a pump on the end of the actuator arm.

All of these problems just lead to increased build time. Obviously your machine is quite expensive - so if it takes 2 extra days of machine time to build a house on a steep grade in rocks, then thats gonna cost more, and at some point might make it not worth it.

[vlozko]

By rocky, I’m not talking about pebbles and small stones. I’m referring to boulders and ledge that may need blasting. It happens quite often up here and most of the time excavators may not know about these issues until they start digging.

> Well you dig it till it is the same shape as the plan...

That’s not how it works. Either the surrounding property needs to be regraded, in which case you’d still be forced to use excavation equipment, or you’re making an even more complex machine to be able to support building things like walk out basements on a custom grade. In the case of basements there’s simply a lot of volume of material that would need to be either removed out of a lot or just moved within the lot. Again, still needs excavation equipment to do that. The same excavation equipment that can dig out a foundation within hours and is perfectly adept at dealing with boulders.

A machine to handle other parts of the job such as foundation pouring might be viable. I’m just saying that a magical machine that can do it all if left alone for a few days is wishful thinking.

[bluGill]

Cement is not a great material for building a house. It is weak in compression (normally made up for by using a lot of it), it has terrible insulation, and it is hard to modify when you want to make a change. 3d printing of buildings is a niche and I predict it always will be.

[londons_explore]

3D printed things in general tend to have poor (weaker) material properties.

I predict that that won't matter eventually though, because over time, the cost of human labor goes up and the cost of materials goes down (relatively). That means anything that reduces the labor cost to build a house will always eventually happen, even if more materials are needed (unless another technique reduces the labor further first).

[eightysixfour]

You mean like ICON?

[londons_explore]

Yes, but I think their printer design could be improved.

I would go for the printer being far less weight by making the whole thing a cable truss and winch structure. That should cut the hardware cost in half or better, like the way a travelling circus tent can be assembled entirely without a crane, yet packs into a tiny box. The downside is you can no longer assume a rigid structure, so you need cameras and alignment marks for precise positioning - but you probably needed them anyway. You also can't make any accelerations above 1G, but that should be fine for housebuilding.

And obviously, their design only makes the walls, but I would want to do foundations, roof, insulation, plumbing and electricals all with the same machine.

[secabeen]

Yeah, getting plumbing and electrical as part of the print seems key. The current ICON system looks cool, but at the end, you have a concrete structure with no openings for these elements. Pictures of ICON buildings show electrical installed entirely with visible conduit, and protruding J-boxes, and don't show rooms with plumbing at all. I don't think many home-buyers would want a home without utilities embedded in the wall as in traditional construction.

[eightysixfour]

The hardware costs are minimal compared to other costs. It packs into a container.