More practical concerns would be plumbing for the fake house, the HVAC, and the interior finishing. If they want it to look like an actual house from the inside (remember that Sam tries to be a perfectionist) it will be expensive and time consuming. A significant percentage of the cost of just building an actual house. Then there's the issue of the continuous occupation for 6 weeks - most industrial zones absolutely prohibit that. Then there's the issue of demolishing and removing the fake house they've built once they're done