Damn, that floor must've been used the ironing feature. And the wood filament got really good up there, even extruding some metal plates in the process.
But seriously, the whole "3D printing buildings" thing only ever gets viable once they finally build a well portable machine with multiple extruders (for insulation etc) and, more crutially, a robotic part-picker that can install pipes and crossbars inbetween the print job. And all that with good price/performance ratio.