Prefab homes are built by using some kind of prefabrication method to either manufacture the main building components (like walls, roof or floor) or the entire house in a factory-like environment, at a different location than the site of use.
With a good amount of the construction carried out offsite, under controlled conditions, building a house prefab increases the certainty of the building process. It is faster, cheaper, more sustainable and, over all, of a higher quality than traditional construction.