Here is a small house that can be put up in a whole day! Obviously they construct the majority of the house prior to the build indoors. But still it is kinda neat. The prefab house uses SIPs or Structural Insulated Panels to make up most of the house. As for the look of the house, frankly they lost me at the top portion. It isn’t very appealing and doesn’t really flow. Regardless, the house does have a strong use of eco-friendly materials and is super efficient.