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Swiss Subalpine Timberframe Designs #33544 02/20/16 04:56 PM
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D L Bahler Offline OP
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I talk a lot about Swiss Timber frames, obviously it is my passion and area of study. I'm very fond of the sorts of techniques and solutions that this culture developed over the centuries. I find the methods they use to be unique and ingenious.

It occurs to me that with so much talking, I have done a poor job of actually sharing useful images and illustrations. I have a number of models, so I thought I'd share some of the different techniques with you here.

So i'll share some images I've created so you can have a better look at some of the details. First I'll post up images of a few different style, then I will step back and discuss a bit of what's going on.

First is the 'modern' (we'll get into that later) style of light timber construction. You might recognize this as essentially the same style of framing used in German half-timbered buildings(Fachwerk) of later (post 16th century in most cases) construction, but it is not necessarily a half-timber construction method. In Switzerland it is often used in situations where it is meant to be clad over or concealed, although it is also seen in half-timbered construction as well. When viewed as a framing method, the Swiss call this 'Riegelbau' and the Germans have a variety of terms such as 'Geschossbau'. Fachwerk refers in both cultures to half-timbered construction in general.



This is a very very basic illustration lacking any framing for doors and windows, and only showing a single partition necessary for supporting the middle of the cross beams (this building is 30x40 feet).
The Roof structure is a simple 'Liegender stuhl' system, here shown without the common rafters which would be bound together at the peak and fastened to the purlins without a birdsmouth of other such joint, and extend past the lower purlins several feet.

Corner posts are larger, here 6x6, with the inside corner removed. The posts located where two walls intersect are also larger, here 5x6, and have both resulting inside corners cut out. All other posts are small, here 4x4 which is more or less the typical size (old examples use whatever local standard inch existed at the time, and anything built in the last 150 years or so uses metric, so measuring timbers with an american rule is not likely to give you a nice clean number)

The different levels of the structure -ground floor, first floor, and roof structure- are all essentially separate frames stacked atop each other. The method of capturing the cross beams between two timbers (using a special joint called in German Kamm or comb, which is basically a category of cog joints) creates a very sturdy structure without the need for tall posts extending the entire height of the structure.

Here long braces are used, which became the standard practice throughout the broad region where this style of framing is practiced probably in the 17th century, maybe a little later. These braces do not join to the posts at all, since the smaller posts can not afford to have joinery cut into them without sacrificing their strength. In theory, such bracing is less efficient that corner bracing since it does not create true triangles, but in practice it is more than sufficient.
It is not uncommon to see this executed a little differently, where instead of employing timber specifically for the purpose of bracing, one of the posts is inserted at a slight angle.
These braces must be matched to work -a brace leaning one direction must be matched by a second brace leaning the other direction, or else it may actively push the building over! When set in pairs, these braces rely on the weight of the building to keep things square -in order to shift against the brace, it would have to stand upright, pushing the plate above it upward. The weight of the structure and the pegs joining the posts to the plate prevent this from happening.

THe connection on the gable side between the two stories shown here is the most common, but not the only way it can be done. You can also some times see where there is a separate top plate and sill joined at the same levels as those on the eaves sides, often reinforced with a steel or iron strap.

This style of building originates in urban framing methods of the late Middle Ages. There is a lot of debate as to when, where, and why this happened. It's likely this style originated somewhere on the western part of the Swiss Plateau, either in Germany or Switzerland, some time around the year 1500. I believe it to have been developed as an inexpensive and practical way to construct homes in the poorer sections of the old stone cities such as Bern and Basel. That being the case, this would have originated as a half-timbered style of construction -but was quite a bit different than the other half timbering styles already in existence.
I am most impressed by the adaptations of this style to rural construction that happened a few centuries later. This is the style that was adopted as industry and technology spread out on the Swiss Plateau and beyond, because it is so well suited to a more industrial means of producing timbers from trees and converting them into frames.

I also believe this style to have had precursors in the rural building styles that existed along the southern edges of the Plateau prior to its invention. Most of the elements that define this style as something new and unique are to be found in other, older styles that have nothing to do with the half timbering traditions of the cities to the north. These include the platform framing concept and the way it is accomplished, and the way the frame is tied together horizontally.

We'll look at those styles of framing next.

I am quite fond of this style of framing. I believe it to be one of the most ingenious and practical methods of framing ever developed, and very well suited for carpenters working with modern design requirements, modern conversion processes, and who rely on transporting things over a great distance (these are the primary reasons it replaced the older methods in Switzerland). If I were building for pure practicality, this is the method I would use. It's also very well suited to prefabrication -some all-wood adaptations of the style used in Switzerland today assemble entire wall sections in the shop and ship them to the job site ready to be placed by a crane. A entire large house can be set in place in a day.


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Re: Swiss Subalpine Timberframe Designs [Re: D L Bahler] #33545 02/20/16 05:20 PM
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D L Bahler Offline OP
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The next style of framing is a mixture of log and timber technologies, resulting in something entirely new:



Here I have executed part of the structure with the log infills and window framing that go along with the overall style, but also omitted these on another part to show the basic framing more clearly.

This structure is divided into two sections separated by an open hallway (called a Tenn) but united under a common roof. The front section is a house while the rear is a barn. It is common to see these two sections framed in different styles, as shown here. It's not completely understood why this is the case, although the two section were usually built at different times. The arrangement shown here, with a platform-framed house and a tall-posted barn, is very common, owing likely to the fact that the barn is usually framed more crudely. The barn is also not usually a hybrid, but is a pure timber frame. (One theory is that the two framing styles are evidence of the two different cultures that settled this region combining to create something new and unique.

This structure actually does a decent job of illustrating both the hybrid construction style of the subalpine ranges and the timber framing style of the Swiss Plateau if the two halves are examined separately.

Like the previous method of construction, this is a method of platform framing. This possesses a distinct advantage over the timber framing styles of the plateau in that the layout of the rooms above are not bound to the layout of the rooms below. This is a concept learned from log building. Here we see on the front there are two room on the ground level and three rooms above. This building possesses log gables atop a timber frame. This used to be common and 150 years ago would have been found all over the northern verge of the Alps, but today most of these structure are gone -the log gables replaced with steeper timber framed roofs- and only a handful remain.

This particular style illustrated here uses a double beam assembly where the two stories meet, but this is not the only way it is done (although it is the way I like the best) some use a single timber here, joined on a single level still.

As far as heavy timber framing goes, this is my absolute favorite, with or without log infill. In its home region, this sort of framing is always seen with heavy timber infill as shown here, because it is actually an adaptation of the older log building tradition. I can't give any dates on when this developed, only to know its heyday seems to have been about the 16th century, and much older examples still exist. This to me along with the history of settlement suggests this style began to develop as early as the 8th century, when settlers from the north began to arrive in the region already settled by people from the Alps to the south. The former carried with them timber framing techniques into a region dominated by log building (we see a declining influence of timber framing the further south we go, with a few scattered examples existing in the mountains such as the dominance of a timber framed lower story and log built upper story in the Simmental region, and the rare occurrence of timber framed roofs atop log structures dating from the 16h century and earlier)


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Re: Swiss Subalpine Timberframe Designs [Re: D L Bahler] #33546 02/20/16 05:29 PM
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D L Bahler Offline OP
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The third style is included here for comparison to see where certain concepts came from. This is the Alpine log house.



This type of construction is very simple. Log corners are interlocked, courses are stacked directly and sealed with a spline or double spline and secured against lateral shifting with stout pegs every 2 to 3 feet. Windows and doors are rigidly framed into the log shell. Typically even the gables are of full log construction.

Purlins are supported with heavy log buttresses, whereas in a timber frame from the same general area would require heavy struts to accomplish the same purpose

Certain elements can be tied directly to the hybrid framing style -the framing of balconies (a universal feature throughout much of Switzerland) the different arrangement of rooms from one story to the next, even the connections used in horizontal timbers in the hybrid frames are the same as those used in log corners.

The last picture illustrates a common shortcut, where uprights are used at the corners instead of interlocking joints. The uprights are not posts, because they do not bear the vertical loads of the structure.

Next I'll work on getting some good images of the old style of timber framing from the Swiss Plateau.


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Re: Swiss Subalpine Timberframe Designs [Re: D L Bahler] #33547 02/20/16 09:53 PM
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D L Bahler Offline OP
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Here are some pictures of a timber frame in the style of the Swiss Plateau. The particulars of this example are in line with the architecture of the Lower Emmental region (roof shape, design of the roof structure, and layout of the rooms in the house)

Like the hybrid house shown, this incorporates a house and a barn under a single roof.




Unlike the other timber frames shows, this style of framing is built around the support for the roof. Essentially this sort of timber framing developed from a simple framework designed to prop up a ridge beam and evolved from there. The primary framing members in this particular structure ae the tall posts that support the eaves walls and the middle purlins. This sort of frame is called 'Mehrständer-riehenbau' or multiple post-row construction since it relies on multiple rows of tall posts to hold up purlins. It evolves from an older style that simply has a single central row of posts to hold up the ridge beam and eaves wall posts. Here the ridge beam is supported by posts footed onto a cross beam that rests atop the middle purlins rather than extending clear to the ground.

This sort of roof framing lends itself naturally to the construction of hipped roofs. The example here has a half hip on the front and a full hip on the rear (I am quite fond of this arrangement personally)

The rafters are typically unbraced and seldom attached to anything other than the ridge beam. The roof support system is often excessively braced to account for the lack of bracing between rafters.

The wall frames here are shown without bracing. If bracing is used, it is typically in the form of let in dovetail braces. This is paired typically with a thin plank infill between the posts. Often houses have a heavy timber infill, in which case bracing in the frame is unnecessary and is typically omitted.

Notice the projected support for the purlins past the eaves walls. This provides excellent shelter for the structure and creates broad usable spaces along the exterior walls. Typically these houses have eaves side balconies as shown -the broad overhangs allow better head space in this area.


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Re: Swiss Subalpine Timberframe Designs [Re: D L Bahler] #33548 02/21/16 04:49 AM
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Jay White Cloud Offline
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Thanks David...Keep them coming...

Re: Swiss Subalpine Timberframe Designs [Re: D L Bahler] #33549 02/21/16 05:08 AM
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D L Bahler Offline OP
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Jay, any thoughts or observations? We've discussed some of these things in detail privately, and I've said some things here that I hoped my pique your interest and spark some debate (like my assertions regarding origins and time frames of development)

Most of all, I'd like to see your perspective in a broader sense how unique some of these concepts really are -they may have analogies in other cultures, even if such is not to be found among their close neighbors.

I'm very fond of the designs of these timber frames -so very logical, and I can look at them and easily figure out exactly why things were done the way they were, and why things evolved from one form to another. Every aspect of the design can be connected directly to an adaptation to changes in resources, climate (as people migrated out of the mountains onto the plains, or vice versa) and technology. I'm fascinated as to the whys in regards to timber framing techniques, and tend to discard ideas that I can't connect to a logical impetus. This drives my own notion that there has to be a good 'why' to the things that I do. I am a great admirer of the old archaic building forms, for example, but also concede that they are not the most practical way of going about things with access to modern technologies.


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