If that part about being able to work inside the structure while it's going up is true, that could be a game changer. So much easier to lay pipes and wires down in grooves than to thread them through holes. And if you can place windows and doors during construction you don't need extra bridging support for the concrete...

How is the second floor poured?

I don't see cement as energy efficient for living in. What is the energy consumption like for this kind of building?

I’m guessing the manual labour involves laying timber/composite floors and the printer just deals with the vertical elements of the construction?

If it can't be done cheaper and faster, and in the end a competitively efficient product, then it's not gonna fly.

Better to use foam concrete, lighter, cheaper, better insulation, better earthquake resistance . It can be reinforced with fibre for added strength.

how long will it last?probably needs waterproofing

precast walls ,that bolt together is better i think

Jeffery Green - Since the walls are hollow, I'm assuming they're filled with foam insulation.

Stan Mitchell - 'DryLock' or Dupont 'Stonetech' will take care of that.

Bahbah - Aircrete or foamcrete can't be sprayed, it destroys the bubbles.

How about mixing ground up plastic waste as an aggregate (like sand) with the cement? Reduces weight, amount of cement, and re-uses all types of plastic.