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#34322 - 01/12/18 04:29 PM Traditional layout techniques for hips and valleys
Jon Senior Offline
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Registered: 05/04/11
Posts: 132
OK. I'm giving a talk in a few months to a group of non-carpenters about traditional french layout (Trait de Charpente). As a part of it, I'd like to include a comparison with other (probably mostly European) techniques for the layout of "complex" joinery such as those found in hip and valley timbers. I would distinguish these joins from the "simple" truss which represents one plane. (A hip being the intersection of two planes, it cannot simply be laid out using the roof pitch directly).

Were hip rafters simply calculated (application of trigonometry)? Or measured in situ as the roof was assembled? Or did historic builders limit themselves to certain pitches for which the ratio of rafter to hip rafter lengths was known? How were the cut angles established for the rafters that meet the hip rafter (Sorry about the lack of terminology here... I actually only know these terms in French)?

Above all... can anyone cite a reference source (book / website) that discusses some of this? I've looked through my original edition Audels, and the various timberframing books in my collection but no light has been shed!

Thanks in advance and hoping that all of this makes sense without the handwaving that I would normally employ to explain this stuff!

Jon
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#34323 - 01/12/18 05:12 PM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Will B Offline

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Registered: 10/02/02
Posts: 197
Loc: Massachusetts
Hi Jon,
The hips were drawn using traditional developed drawing techniques. No math. That's what le trait is all about.
Do you have access to some of the French books like "Le Charpente en Bois" or Mazzerolle's "Le Trait de Charpente"? They are available from the Compagnons du Devoir bookstore, and show the techniques very clearly. There are many other books related to the techniques.

You can also look at my five articles entitled "When Roofs Collide" in the back issues of Timber Framing. I learned much of this from the French and Germans.

I also reviewed the following book in Timber Framing #115, and it's available fro a frre download:
The Invisible Tools of a Timber Framer: A survey of principles, situations
and procedures for marking, by Ulrik Hjort Lassen.
Gothenburg, University of Gothenburg, Gothenburg Studies in
Conservation No. 32, 2014. In English. ISBN 978-91-7346-785-8,
8¼ in. x 10¼ in., 238 pages, copiously illustrated. Available as a
free PDF download at hdl.handle.net/2077/35598 or in print from
the publisher by emailing acta@ub.gu.se. Softcover, 212SEK.


Another website: http://www.historicalcarpentry.com/l-art-du-trait.html
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#34324 - 01/13/18 01:02 AM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Jon Senior Offline
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Registered: 05/04/11
Posts: 132
Thanks Will.

I should however have made it clear that I have no problems with the trait de charpente. It was a part of my carpentry training here and since both my teacher and I were somewhat enthusiastic about it, by the end of my course I was exploring la croche (curved timbers). I'm still trying to get my hands on a reasonably-priced copy of Mazzarolle.

The impression I've been given frequently is that le trait was unique to the French, and what I'm interested in is seeing how much further the French pushed it compared to their counterparts in Europe and the East (China / Japan). Was everyone using basic trait (élévations + vrai grandeur d'arêtier with rembarrement) leaving the French to play with bevel gauge techniques and curves? The problem is that the French are supremely proud of le trait (It's been recognised by UNESCO as an "intangible cultural heritage") and somewhat derisive of other cultures of carpentry making it hard to know exactly where the differences lie.

I've come across Lassen before, but didn't see his thesis. I'll take a look and see if he didn't already cover this ground.

Edit to add: In this video https://www.youtube.com/watch?v=8TmYdAUX6pA the chap with the very short hair helping Eric Lion was my teacher, and my training took place in the same workshop that it's filmed in (albeit some years later).


Edited by Jon Senior (01/13/18 01:12 AM)
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#34325 - 01/13/18 08:44 AM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Will B Offline

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Registered: 10/02/02
Posts: 197
Loc: Massachusetts
Right-o. Your on top of it as I should have assumed from your earlier posts.
My experience is limited to German and Japanese techniques and books on the same, and think that rather than the French taking the drawing methods "further", the traditions diverged based on the architecture and joinery and the material sizes and shapes.
Have you seen the French translation of Manfred Euchner's German book "Manuel des Traits de Charpente" (French title, available from Eyrolles).
I think Lassen's thesis is a good survey of the various techniques.
I'd love to do a timber framing tour of Normandy someday....know anyone who could organize one?
Thanks for the video link.
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#34326 - 01/13/18 03:22 PM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Jon Senior Offline
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Registered: 05/04/11
Posts: 132
For a timber framing tour of Normandy I know several people, and can probably get you in touch with François Calame who was instrumental in the trait bid for UNESCO recognition. And if I can't find anyone else (highly unlikely), I'd be more than willing to show you around. Message me and we can talk possibilities.

I'll take a look for that book. I have a feeling I've seen it referenced somewhere before. Another great reference is Émery's "La Charpente en Bois". If you already have a reasonable grasp of le trait then it makes a fantastic reference when you can't quite remember how to find a certain angle or length. Or just when you want to learn something new.

UNESCO seemed to think that there was some unique characteristic of French trait. I'll try and see if there are more details on the decision that might shed some light.
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#34327 - 01/13/18 08:58 PM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
timberwrestler Online   content
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Registered: 11/07/05
Posts: 281
Loc: Becket, MA
I have no idea about the chronology of this, but the Chinese, Korean, Japanese, Germans, and the English (and presumably more) definitely knew how to do compound joinery with the same methods. There are some subtle differences, but they all worked with the same basic (or really not so basic) triangles. It would be interesting to study the dates of those crazy roof frames, and see who had the earlier versions.

I'd be interested to hear whether there is something unique about the French version.
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#34328 - 01/14/18 01:20 AM Re: Traditional layout techniques for hips and valleys [Re: timberwrestler]
Jay White Cloud Offline
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Registered: 11/06/08
Posts: 534
Loc: Vermont
Hello Jon, et al,

Gosh its been a while...Great subject to bring up! One of my favorite topics to study and learn in timber framing...Thanks for the video link, and there are several more on the subject which are enjoyable to watch as well...

To validate, having been a student of timber frame Layout Modalities since the early to mid 70's starting with Dutch Germanic version, and moving into Asian and related systems, I have a varied and perhaps alternative perspective on certain matters pertaining to this subject?

First, what I believe is often overlooked, is most of the richest and unique systems of layout (~70%) have never been document in any way. These where only passed down directly from Master to Apprentice, as it has been for millenia. Douglas Brooks has noted similar observations with his particular specialization in esoteric Japanese Boat building practices. These can (as are found in other sea faring culture from the Middle East on) involve lofting strategies that can incorporate both horizontal (floors) and vertical (walls) in accomplishing the task of rendering complicated layout...especially on curves...similar to what is found in la croche (curved timbers) layout.

Quote:
The impression I've been given frequently is that le trait was unique to the French, and what I'm interested in is seeing how much further the French pushed it compared to their counterparts in Europe and the East (China / Japan).


In my view, the French have taken this to an apex unparalleled in European traditions generally speaking, with only perhaps the German and Dutch Masters following a close second. Nevertheless, this can perhaps only be stated with speaking strictly of the art and craft of timber framing. When we get into Stone Carving, now we have outweighing very similar needs and demands, accept it is applied to stone, and not timber. Here we find (again) oral traditions outweighing published tome by a great margin, and we see the Iberian and Apennine peninsula cultures having very remarkable systems of layout as well primarily for stone, yet also for timber and the construction of ships going back further than the Roman and into the Egyptian dynasties.

Quote:
...Was everyone using basic trait (élévations + vrai grandeur d'arêtier with rembarrement) leaving the French to play with bevel gauge techniques and curves?


No, not in my view. The similarities may be indeed basic, yet the French culture took there system into areas of detail, grace and procedure, others didn't explore in the same way.

Quote:
The problem is that the French are supremely proud of le trait (It's been recognized by UNESCO as an "intangible cultural heritage") and somewhat derisive of other cultures of carpentry making it hard to know exactly where the differences lie.


Yes, I must agree fully, that the term derisive is most germane and applicable. To the point that often one can (individually) find with practitioners of these methods offering a brick wall of close minded perspectives when it comes to the strengths and weakness of their system. No doubt a brilliant system indeed, yet when compared to acient Asian modalitis of layout (et all) that employ not only some lofting systems (where applicable) but extremely advanced templating, and lining systems that few other system can match of speed, ease of application (once understood) and much less labor intensive than most of the "scribing systems" in general. To the point, beyond just Japanese, but Chinese, Korean (et al) methods that allow for curved and live edge timbers to be fully laid out and cut without ever coming near each other or having to be tested prior to raising...

I love the European methods (particularly the French) yet its complexity and laborious nature is far accede in ease of use application by the Asian approaches that also exceed it by about 5000 years in applied use in stone, timber and the building of ship as well as architecture...

Quote:
I've come across Lassen before, but didn't see his thesis. I'll take a look and see if he didn't already cover this ground.


If you don't have a PDF copy of "The Invisible Tools of a Timber Framer" by Lassen, I can email it to you if your email hasn't changed since last we corresponded...
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#34329 - 01/14/18 03:50 PM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Jon Senior Offline
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Registered: 05/04/11
Posts: 132
Thanks for your input Jay and Brad.

Brad: Some limited reading this afternoon suggests that the basic compound joinery techniques required for hip and valley framing were in use by most European carpenters, but it's possible that the curved timber techniques were unique to the French. The UNESCO application doesn't reveal anything unique other than the continued oral education of trait which still forms a part of the modern carpentry diplomas, where such traditions have perhaps been lost in other cultures. (I know that Tedd Benson admires the French compagnonnage).

Jay: I've downloaded Lassen's thesis, although he seems to be more concerned with the actual approach to using a plumb line (which formed the basis of another paper of his that I have), than with the layout techniques used to position the timbers in the first place.

To be fair to them, most of the carpenters here with whom I've discussed trait are aware of the long standing timber frame cultures in Asia, and the most close minded comment I've heard yet came from an apprentice architect who was rapidly corrected by his carpenter peers when he said "but French carpenters are the best in the world aren't they?".

With regard to the beauty of trait, I still remember the moment when I learned to produce the "engueulement d'aretier" (the cut at the top of a hip / valley rafter where it meets the post, or ridge beam) using the "sauterelle" technique. Rather than producing the actual cut plane on the floor and tracing that up onto the timber, you find the angles which can be reproduced onto the timber using a bevel gauge. After tracing some long lines on the floor (without necessarily understanding why), the angles appeared and I duly traced them onto my timber. I cut the joint and for the first time since starting my diploma, when I presented the timber the joint mated perfectly first time. It felt like magic. Interestingly the compagnons are often trained with a heavy emphasis on the sauterelle which makes their trait more complicated relative to the simple subjects for the first level diploma exam and results in them often being a little more pushed for time! That said, once you've mastered it, the advantage is being able to work from a scale drawing with just the timber lengths and the angles, and not needing to keep moving timbers around.

Do you have any good starting references for the Asian layout systems. While I'll probably not get my head around them in time for my little talk, I'm still very interested.
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Contemporary Norman longhouse in Normandy

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#34330 - 01/14/18 10:22 PM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Jay White Cloud Offline
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Registered: 11/06/08
Posts: 534
Loc: Vermont
Quote:
...but it's possible that the curved timber techniques were unique to the French.


I agree Jon. In my understanding of the system and its comparative to other systems, the French modality is unique.

I would also note (and agree) by and large, the French practitioners are respectful (for the most part) of other systems and even interested in them. I also find that these systems are different enough to hold entirely difference approach avenues to the solutions of rendering complex joinery; especially in curved/live edge timbers. As such, I believe that the "style" of French architecture itself had a great effect on the layout system, and perhaps why it has endured intact as long as it has.

It has also been observed that normative cultural effects could well be at play here, in as such, that old guilds didn't not change or adapt systems from..."what they where to anything new"...as to not only protect triad secrets, honor there forbears methods but also to keep systems (and the complexities) as unchanged as possible. Such enigma within layout systems often became cornerstones of "trade craft" for Guilds in both Europe and Asian as well as other cultures that had them.

Quote:
Do you have any good starting references for the Asian layout systems. While I'll probably not get my head around them in time for my little talk, I'm still very interested.


Alas most are either direct observation, related to me orally, or in the original language.
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#34333 - 01/15/18 05:35 PM Re: Traditional layout techniques for hips and valleys [Re: Jon Senior]
Will B Offline

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Registered: 10/02/02
Posts: 197
Loc: Massachusetts
Jon,
Have you seen Chris Hall's blog here: [url=http://thecarpentryway.blogspot.com/][/url] http://thecarpentryway.blogspot.com/
His books are excellent, and the similarities to French and German layout evident, in my opinion. Again, the drawing methods are similar but the joinery and architecture are different.

I suggest that Asian carpentry shows as much curved and crooked timber work as French, if not more.
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