The Germanic tribes were semi-migratory people. The developments BC were a transition from hunter-gather to farming communities. However, these communities could not be permanent over a period of generations, because the people did not understand the importance of replenishing soil nutrients, so as a result they would over time deplete their farms, and have to move on to new lands.
The Germanic tribes in particular moved a lot, and underwent long periods of migration, most notably the early medieval Great Migration, where tribes systematically moved in and picked apart the remnants of the Western Roman Empire -establishing Germanic dynasties in the previously Roman territories of France, Britain, Switzerland, Spain, and even Italy. Another example being the Viking Age.
This all ended when the monasteries introduced a new farming practice, crop rotation. They introduced the 3 field system, and so Germanic farming communities suddenly became permanent.
As far as descent from Roman tradition, I would love to agree with that, but everything I have read claims that is not so, at least not to a very high degree. IT is generally agreed that he Roman techniques were lost and building across western europe reverted to post building for a few centuries. As far as I can tell, roman techniques are thought to have only survived in roof framing.
The half timbered design is shown to be descended from post building, with an intermediate style with posts set on stones and an externally braced frame, similar to the Norse langhús
[img[http://upload.wikimedia.org/wikipedia/commons/d/dd/Fyrkat_hus_stor.jpg[/img]
which leads to styles similar to the alpine Ständerbohlenbau or Scandinavian Stavverk, which seems to lead off in 2 directions. This style ultimately develops in some regions to half timbering, essentially the wood panels are replaced with stone or brick or some such. In other regions, the posts are eliminated and the style becomes log building. It is believed that both half timbering and log building are developed from the post built house.
I dont think it would not be entirely accurate to categorize Ständerbohlenbau as Fachwerk, and I don't think that the Germans do, as the word is generally intended to refer to a half timbered structure. But it is an important step in the development of the style.
I had found a Swiss website once with information on Ständerbohlenbau and historical development, but I don't know if I will be able to find it again.
