Here's my pitch....
I hope to generate some interest in this style of timber framing, and bring it more to light. My goal is that this style might be considered a genuine option for a timber framed home in North America.
First of all, some history. Some of it you probably know, some of it you may not.
American timber framing today is descended from a colonial style that was more or less an adaptation of the British style, along with a few infusions from Dutch and North German building styles. The arrival of thousands of settlers from the southern German lands, collectively known as the Pennsylvania Dutch, was really to late to really have much of an affect on the style of the frame itself -thy would build their frames according to the established American methods. Its only real effect was on the profile of the frame itself, and the design of the building as a whole. The south German style survived in America only in a few small instances of isolated communities. Even the Amish would come to build their frames according to the American style. The biggest reason for this is that it was the cultural norm, the way that the locals did things. "when in Rome..."
Another possible reason may have been the availability of tools, though I am not convinced that American tools would have made it any more difficult to make a German frame.
As for the German frame itself, it has a very ancient lineage. The frame design is the result of a fusion that occurred during the middle ages, but ultimately began as soon as the southern tribes (here we will ultimately focus on the Allemani) settled in Roma lands. The German frame developed when the earth posted frame of the migrant tribes came in contact with the far more sophisticated frames that the Romans were accustomed to building.
In the middle ages, advances in farming techniques marked the end of the transient days of the Germanic tribes, They settled down in one place, and established farms that would remain in one family for generations. As a result, they started building structures that would last for generations as well. They had already been doing this since they took over the old Roman cities. They knew how to build lasting structures, they just didn't see the need to do so if they were just going top have to move once their farmland was exhausted.
Timber framing reached its height from the 15th through the 17th century. At the end of the 1300's they developed a style that is still in use to this day, and that style rose to be the dominant form of timber framing by the late 1400's in all but the alpine regions, where log building was preferred (and still is to this day)
This style developed to make use of limited resources, yet it is quite well suited to making structures of tremendous size as can be seen in the traditional Bernese Bauernhaus.
This system has survived into the present day, and has only been marginally replaced with modern methods. The Allemanic people are, after all, fiercely traditionalist people.
The particular style that I have focused my study on in what is known as the Allemanic Style. The feature that most distinguished this style from other German styles is its simplicity. It generally does not make use of the complex decorative bracing frequently associated with German frames, and is designed first and foremost to be functional. The amount of timber used is generally the amount that is practical and sound. No more, no less. It is not exactly minimalist, but it is not ornate either.
Each floor of the structure is framed semi-independent of the others. There are no posts that extend the full height of the walls. The framing of each floor can be thought of as similar to stick framing, in that each wall is made of a rectangular frame.
Another feature is that there is no use of any bent or other cross sectional framework at all. In fact, there is nothing that can really be categorized as a tie beam at all. Instead there are a number of stout timbers that simultaneously function as floor joists and as ties, providing direct support to the floor and resisting outward thrust at the same time. On wider buildings these are joined together at a beam running through the middle of the building, rather than being cut to the full length. This tie-joist system allows for significantly less joinery to be cut. The joists may or may not join to the plate above a post.
Traditionally the braces are very long, slanting between two posts, but actually being joined in many cases to the sill and plate rather than to the posts themselves. The result is a lack of true triangulation, but the network of bracing both in the walls and in the roof structure (where true triangles certainly exist) tend to be more than sufficient. The braces are often lapped, but are sometimes mortised as well.
The roofs are not built with trusses, but rather are purlin framed. The purlins can be supported by direct posting (stehender dachstuhl), but are also commonly supported with a truss system called in German Liegendem Dachtuhl, which more or less could be translated as leaning truss (lit. reclining roof chair) Stuhl (chair) is often used to denote a roof-support system. The advantage of the latter is an almost totally open roof space.
The advantages of this system are largely the same advantages that caused it to catch on in the first place. It makes use of much smaller timbers, and each individual timber is not nearly as critical as it would be in a structure with wide spaced bents. This allows the use of smaller timbers, either from smaller trees (which is attractive if you are doing it all by hand) or multiple cuts from a single log. The design of the system is such that you can use much shorter timbers as well. There is no need for long plates, or even for long ties. The roof system is even designed so that short rafters can be used.
The joinery is also very simple and straightforward. complex scarf joints don't seem to exist except perhaps in the long purlins, and there are no complicated post/tie/plate connections. While there is more joinery to be done since there are more total framing members, the joints are all very simple.
There is no excessively heavy lifting. Such a frame can be erected without the use of any sort of crane or raising poles, or any such like. There are no bents to raise and so there are no multi-ton assemblies to carefully fly into place. A crew of 3 or 4 would be plenty sufficient to build the entire structure, even without a crane.
The smaller cavities between posts makes the infill question a whole lot easier to answer. many small spaces are a whole lot easier to enclose than few large spaces, and the amount of extra framing to support any non SIP, non natural wall system would be minimal, in same cases all the would be necessary would be small board to support drywall.
IF you are building with dried wood, smaller timber are far less expensive to kiln dry, and take far less time, and are far less susceptible to splitting and excessive cracking. If you are building with green wood, smaller timbers will move significantly less in a completed frame.
I plan on traveling to Germany and Switzerland in the near future to study the buildings up close and thoroughly document the framing and joinery involved, as well as variations in regional styles. In the mean time, however, there is quite a wealth of information available on the subject online if you can read German, including complete listings and diagrams of every timber joint known in Germany, and schematics of every 'dachstuhl' ever used. The Germans are after all known for their precision and detail.
I do admit a certain bias to this particular style. I am myself of very strong Allemanic Swiss heritage. I grew up looking at pictures from the old country, and with the idea that that is the ideal life, and those are ideal homes. However, I do think this system has a lot to offer us today.
D L Bahler
