I'm not sure where you're getting 'by a single person' from, or 12 days,
and us$500/day seems generous for a 1 man shop.
But given the cladding and roofing in the photo's, I'd imagine a 2 man crew could build a house in roughly that many working days. Probably less.
When I was working as a builders labourer, we'd show up on-site with the concrete pad already set. Take ~ 1 day to stand-up the frames. ~ another day to stand up the roof trusses, ~1-2 days to put the roof purlins and any internal gutters in (the buildings shown won't have those). And another day or two for putting tar-paper on the roof, tyvek around the frames, and general tidy up
A contractor would take ~2 days to put the roof on.
~1/2 day for the electrical pre-wire.
~1 day for the plumbers and drainlayers to pre-place everything
1-2 days to fit the windows and doors.
The style of exterior cladding shown is comparable to the roof, so another 2 days. (Most of the houses I worked on had brick cladding over a timber frame, which took ~4 days for a single story house)
Plastering, (2 days) Painting (1 day), electrical post (~1/2 day) plumbing post (~1/2 day). Cabinet work (1 day) carpet (2 days)
So ~19.5 days to build a conventional house.
We can eliminate the carpet straight off.
If we use structural insulated panels we can eliminate the cladding, roofing, papering, and time to install the purlins. That's ~7 days saved right off the bat.
The depicted houses are on concrete block stilts, which will need a day or 2 to build, and there needs to be some extra time allocated to building and insulating the elevated floor, but I don't really see why that has to be hugely expensive.
The depicted structure is small, and doesn't appear to have AC. the foundation, plumbing and drainage don't look like they require extensive use of excavators (although you will need some for the drainlayers at least).
So with 2 people, plus the drainlayer contractor and his baby excavator, I don't think they're all that far off a reasonable construction cost.
But given the cladding and roofing in the photo's, I'd imagine a 2 man crew could build a house in roughly that many working days. Probably less.
When I was working as a builders labourer, we'd show up on-site with the concrete pad already set. Take ~ 1 day to stand-up the frames. ~ another day to stand up the roof trusses, ~1-2 days to put the roof purlins and any internal gutters in (the buildings shown won't have those). And another day or two for putting tar-paper on the roof, tyvek around the frames, and general tidy up
A contractor would take ~2 days to put the roof on.
~1/2 day for the electrical pre-wire. ~1 day for the plumbers and drainlayers to pre-place everything
1-2 days to fit the windows and doors.
The style of exterior cladding shown is comparable to the roof, so another 2 days. (Most of the houses I worked on had brick cladding over a timber frame, which took ~4 days for a single story house)
Plastering, (2 days) Painting (1 day), electrical post (~1/2 day) plumbing post (~1/2 day). Cabinet work (1 day) carpet (2 days)
So ~19.5 days to build a conventional house.
We can eliminate the carpet straight off.
If we use structural insulated panels we can eliminate the cladding, roofing, papering, and time to install the purlins. That's ~7 days saved right off the bat.
The depicted houses are on concrete block stilts, which will need a day or 2 to build, and there needs to be some extra time allocated to building and insulating the elevated floor, but I don't really see why that has to be hugely expensive.
The depicted structure is small, and doesn't appear to have AC. the foundation, plumbing and drainage don't look like they require extensive use of excavators (although you will need some for the drainlayers at least).
So with 2 people, plus the drainlayer contractor and his baby excavator, I don't think they're all that far off a reasonable construction cost.