Monday, August 20, 2007

Heartwood week 1: Intro to Timberframing, or Square rule Rules!

What a great experience.
I have been trying to get my thoughts together about this for a while. I am two weeks back in Holland and the false alarms about the impending arrival of child deux have petered out for the moment (again) so I suppose there is no excuse for putting this off until I come up with the perfect description of every moment.
My first week at Heartwood was a workshop on square rule timberframing. I have posted a little bit about it here, but I promised myself when I had the chance I would make the time to expound.
The Heartwood School was set up in the late 1970s to provide instruction to people who were interested in building their own homes- be it to save money and construct more energy efficient structures (anyone remember waiting in long lines to get gas?) or to invest one's own energy into creating a beautiful hand-built home to live in.
The south side of the schoolhouse showing the porch off the main classroom and the greenhouse.

When interest in timberframing took off in the area in the 1980s, Heartwood began to incorporate more classes in this traditional joinery technique. The first week for me was a workshop building a small cabin from locally milled eastern white pine using the square rule method of cutting joinery. Basically, this means that intersections on timbers of varying size are reduced to a common dimension at the joint allowing one to make structural connections without milling every piece to a standard. Its an ingenious way that traditional builders dealt with material before modern milling. This site has a nice overview of the differences between the two main methods of cutting timberframe joinery.
There is more to it than that of course- and for me that is really part of the great appeal of traditional building; to my mind these methods deserve to be studied and practiced for their value in creating beautiful, living structures and because learning and teaching them requires requires people to invest in and commit to making better, healthier places to live. If you are interested in how people made (and make) these amazing and soulful buildings, you have to appreciate the personal investment in the craft; it is really hand-crafted- the real skill and knowledge can't be bought.
Just moving the timbers around the yard that first day- organizing everything into some logical order for the week- was such a relief after weeks and weeks of reading about the framing process. You don't get splinters from books, but nothing beats seeing the grain of the wood and imagining what you can do with it...
Before we did anything, Will Beemer (our fearless director) gave us a primer on keeping our tools sharp- apart from knowledge about materials, the most critical part of successful cutting.
The first week's workshop was an introductory course; our project was a 12'x18' cabin with a small 9'x8' shed-roofed ell to provide for a small kitchen. The basics of cutting joinery for the frame were deceptively simple but provided everyone a chance to become familiar with all the joints you would need to build almost any sort of timberframe. One of the very cool things was the hand tool training. We eventually broke out this big dog, as well as this productive monster; but for the most part we used only hand tools. Chisel and mallet, handsaw, rabbet plane, spokeshave- it was amazing how quiet and calm a site can be when everyone is working by hand. No compressor noise, no cords everywhere, no dust kicked up by high rpm blades- you could actually hear the wind and the birds! After a while you realize that in many cases you can work just as fast, and safer with sharp hand tools. Plus you get the joy of cutting housing waste with an ax- surely a most underrated tool for most modern carpenters!

The essence of square rule- the diminished haunches and housing of a tie beam (if I remember correctly its position...)

One of the larger members of the frame- a top plate that will land over the posts and couch all the rafters as well. This was a stick that you had to really keep oriented in your head. one of the most important skills is being able to visualize the 'castle in the sky' - being able to orient yourself by looking at one piece and knowing where it fits in the whole frame.

Stick by stick, after four days of laying out and cutting, on Friday the frame grows on site in Connecticut about an hour and a half south of the school...

A critical juncture- the more joinery coming into one spot means less room for error, and more to keep track of when laying out.

No ridge beam in this frame, sheathing will eventually tie the roof to the rafters. Everything in the frame is pinned to together with hardwood pegs. Since it was a relatively small frame we even had time to mortise and tenon the rafter peaks. An interesting note about pegs- they don't function like a nail or other fastener in timberframe joinery- each joint is designed to function on its own, holding members in tension or compression without a fastener- the pegs make raising easier, draw joints together (by a very clever technique of offsetting peg holes to create 'drawboring'), and fix the wood during shrinkage.

Bringing the shed joists together with truck straps; the undersides of the joists are reduced and then tapered to strengthen the members without having to make everything larger to carry the joinery- they also look very cool when exposed. We used an adze and spokeshaves to make these curves.
The raising itself is a crucial process in timberframing- not only for the fact that this may be the first time you fit all the elements together (a real test of your layout and cutting prowess) but also because it has to be a cooperative effort getting everything in place safely by hand. The experience of every frame is unique- the knowledge and skills to do this right have to be learned by doing; there are manuals and treatises of a sort to gain some of the background, but the spirit of the craft is honest involvement in the process.

It was a lot packed into a single week, and more than I can wrack from my melon at the moment, but I hope this is a start to sharing some of my thoughts on what became a very intense seven week trip through timberframing.


Bill Maier said...

Mike - I have been waiting for this.....looking forward to next week's rundown.

glad it was an awesome experience for you.


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