Timber Frame Questions and Answers
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Q: How does timber framing fit in a green building environment?

A: Use local materials. That to me, is one of the major components of a sensible building system. In New England, where I live, our forests are mature again and we have plenty of good timber that can be sustainably and selectively harvested and processed at local sawmillls. Portable sawmills are also very popular that can go right into the woods. All of this avoids the transportation costs, embodied energy and fuel associated with materials shipped from far away, and it supports the local economy. Even with certified timber I would hesitate to buy it if it came from across the country. So for you folks out in the desert or plains without trees, I suggest you look to one of the earth based building systems using local materials, at least for the walls, if you're trying to be truly green.     

Timber frames also are valued more highly, are usually inside the building envelope, and are thus cared for better than a light-framed house. So they will generally last for centuries, as opposed to less than 100 years for a typical modern house. Thus, for about the same amount of framing wood, you get a house that will last 2-3 times longer.

Q: How are timber frames enclosed?

A: The majority of contractor-built timber framed homes use Structural Insulated Panels (SIPs) that get nailed onto the outside of the frame. (SIPs can be the subject of a lot of debate - they have some advantages from a green standpoint - but we'll save that for later.) These go on very fast, thus saving labor (=money), and make a very energy-efficient envelope. But if you're doing your own labor, there are other alternatives such as light framing and Larsen trusses nailed outside the frame that allow you to use conventional insulation or sprayed-in systems, or you can use strawbale or slip-formed earth systems. One thing that is common to all of these systems is that they are outside the timber frame, thus keeping the frame exposed to the warm interior where it is protected. This is important in a cold climate; burying the frame in the wall could cause condensation and rot if the sealing details are not done well. This is not as big an issue in a dry or warm climate, but you still have the problem of finishing your infilled wall up against the sides of the timbers that you avoid by putting your wall outside the frame.