Timber framing: how and why

We were so busy during the fall that we didn't have time to post pictures and explanations of the finer details of the Sunnywood design. As we are now stalled in our building process until spring, we will try to remedy that.
The timber framing process we used was modeled after that described by Rob Roy in Timber Framing for the Rest of Us. Roy contends that while timber framing lends itself to the thick walls necessary for many natural/alternative building methods, most books talk about the craft and art of old-fashioned mortise-and-tenon timber framing. However with inexpensive mechanical fasteners such as brackets, plates, and bolts, "regular" (read, "inexperienced") people can build strong timber frame structures.
Cordwood structures don't require a timber frame. But cordwood is a slow, labor-intensive building method. We finally decided that infilling a timber frame with cordwood, as opposed to building a load-bearing cordwood walls, would allow us to get the roof up on top of the timber frame and lay cordwood under its protection as we had time.
Here are photos of some of the very basic hardware we used to build our "everyperson-style" timber frame. Below, our son Isaac uses a plate to join two beams over a post.





Another thing that Rob Roy advised for a low-pitch (1:12) roof like ours, and which we highly recommend, is to shim the rafters over the beams, rather than cut birds mouths into the rafters. The shims are easy, require less precision, and accomplish the same goal, which is to transfer the vertical load straight down onto the beam. Gravity and friction will hold them in place.
Shims under rafters:

House Raising!

On Saturday, August 30, a wonderful and eclectic group of family, friends, coworkers, and acquaintances came together to help us raise the timber frame and rafters. What an amazing collection of knowledge, skill, sweat, and generosity!!! Here we have set rebar pins in the grade beam and drilled corresponding holes in the precut posts, and laid them out to be raised.
And as you can see, the house-raising crew took our plans and timbers---and raised the framework for a house!

The Rubble-Trench Foundation

Rubble-trench foundations were used extensively by architect Frank Lloyd Wright in the first half of the 20th century. They have fallen out of favor as concrete has become the norm and many code inspectors are unfamiliar with them. After finally deciding that a concrete slab was unacceptable to us in terms of meeting our project goals (because of extremely high embodied energy, high cost---and hard on feet and legs!), we decided that a rubble trench was time-tested and would provide a fairly simple, low-cost, environmentally friendly alternative. We also decided, after much deliberation, to use wooden grade beams (rot-resistant hemlock) on top of the trench, rather than concrete grade beams. We are betting the long-term soundness of these wooden grade beams on the steps we have taken to ensure that very little water ever touches the beams, that any moisture that comes in contact with them immediately drains away, and that, if for some strange reason water finds its way into the trench, it will not freeze before it drains away. A number of people have tried to persuade us to place a moisture barrier under the hemlock grade beams, but we feel that such a barrier would only serve to trap any moisture that found its way to the beams rather than allowing it to drain away. The following features of the foundation and house should keep the grade beams dry and sound:
> appropriately constructed trench dug all the way to ledge, with raised berm of washed stone and good bottom-of-the-trench drainage
> ground sloped away from the outside of the trench/house
> blueboard insulation angled over outside of trench and backfilled with washed stone
> a 2.5' roof overhang to keep water off the walls and grade beam
> a berm and a swale on the upslope side of the house to direct water away from house
(Excavating and filling the trench, and the graywater septic, is the only part of the construction for which we hired a professional contractor.)