Ask HN: Why did 3D Printing buildings never became big? | Hacker News Reader

Ask HN: Why did 3D Printing buildings never became big?

6 pointsmartinbaun13 comments

I have been thinking about this recently as prices of houses just keep inflating up and being so hard to purchase for an average family.

Why didn't 3D Printing buildings became big? It seems like a perfect tech to help us build faster and more consistent.

Clear the ground. Get the 3D printer out there. And then boom 48 hours later you have a building.

Or printing the bricks like Lego so you can just collect them together.

What is it I am missing here?

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The cost of the structure of a modern wood house is a tiny fraction of the overall cost. Most of the construction cost is in the wiring, plumbing, bathroom & kitchen fixtures, windows, flooring, etc. 3D printing doesn't help with any of that. In fact, wiring and plumbing is harder than in a wood-framed building, where you can drill holes in a few seconds.

Also, aesthetic zoning rules are super-conservative. You can't build an unusual looking house in most cities.

ah, so the main cost seems to be the human-part that's hard to automatize, not really the structure/framing etc..?

My uncle runs a framing business. His team can frame your standard residential house in 3 days.

The tile guys take 3 days to tile a bathroom. The cost isn't in the skeleton, but all the things that go on it or through it

thanks Malfist,

and I guess the cost is the wiring and plumbing?

Yes. The good news, if you're trying to develop tech to solve the housing cost problem, is that there are several labor-intensive processes that are easier to develop automation for than building the structure of the house. Like, a robot to wire up light switches is much cheaper to develop and test than a robot to print entire structures.

> Or printing the bricks like Lego so you can just collect them together.

Are construction bricks not already essentially 3d printed? They're 3d objects produced on mass to aid in affordable and standardised construction.

We've been "3d printing" stuff for years just with different methods like injection molding. The 3d printing your referring to in contrast is generally more expensive per unit and the only real advantage of it is its flexibility which is why it's used often in prototyping, but wouldn't be of much use in the mass producing of affordable homes (or anything for that matter).

excellent point. When all you have is a hammer everything becomes a nail.

Homes are already pre-fabricated to the largest possible extent.

Just printing walls out of concrete that won't even have great surface properties is a curiosity at best.

Because I think pouring concrete and putting up steel beams is faster and more stable

In some sense, pouring concrete is 3d printing.

Indeed and this kind of captures the dynamic well. Pouring concrete is quick but the more time consuming part is building forms and tying the steel reinforcements. I’ve been surprised to learn recently that concrete can have a multi-week cure time. So it’s quick to pour but isn’t “ready to go” immediately

Ah, so it might not really save that much time as people still have to setup forms and go/in/out.

The price of houses may be rising, but in most cities the main cost is the cost of the land, not the house.

there a slew of name brand polystyrene foam formboards that remain in place for R value and moisture barrier.

it seems to be the current method and needs no new equipment.

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