3d printing concrete houses

a company that 3d prints concrete houses 

only 3d prints the walls 

not the roof 

and not second floor, so that it's only a one floor house 

3d printing second floor: 

company could 3d print a long tall wall 

and use crane to flip the wall down 

so that wall lies on the ground 

then use a crane to lift wall on top of house 

so that a second floor is created 

then company could 3d print walls on top of second floor 

to create second floor walls of house 

3d printing roof: 

then company could 3d print a tall wall formed like a triangle 

and use crane to flip the triangle down 

so that it lies with broad side on the ground 

then use crane to lift triangle on top of walls of house 

so that roof is created 

there shpuld be openings in the lower part of the triangle 

to enable stairs or ladders 

to reach the inner roof from inside the house 

company 3d prints concrete houses only during day time 

which is probably around 8 hours 

and the company 3d prints a house in 2 weeks 

3d printing concrete is basically silent 

if company received permits from local authorities 

to 3d print 24/7 

then company could 3d print a house in a few days 

and then 3d printing concrete houses 

would quickly outcompete all other types of residential building methods 

and possibly warehouse buildings and shopping mall buildings 

and similar few floor buildings 

it would be a building revolution worth investing in 

3d printing skyscrapers: 

use robot arms that 3d prints concrete walls on each floor 

use robot arms to 3d print concrete walls that are flipped by crane 

and lifted by crane to be used as floor/roof 

use robot arms to plasma 3d print metal beams* of skyscraper 

use crane to lift robot arms to next floor 

when skyscraper is built then robot arms are lowered to the ground 

by elevators 

or by wire 

or by outside tall crane 

or by heavy lift helicopter 

or by future heavy lift quad vtol 

* metal 3d printing is used by a rocket company 

to 3d print an entire large rocket 

by using plasma to heat metal powder to 3d print metal