Timber Framing

Often when we receive specifications from outside designers, the timbers are called out as western wood (Douglas Fir typically) and the most select cuts available in timber sizes. MOST times in traditional Timber Framing, this is unneccessary. We are able to use lesser grades, containing knots. Yes, those clear grades are very nice, but they come from forest stands 3000 miles away, and often from Old Growth timber. More and more, as the lumber industry moves toward growing "fiber" rather than timber, we see a trend where it is very likely that we will never see timber of this size grown ever again. Is your project worth the elimination of Old Growth timber stands? If so, we can still get it today, albeit at a premium. Traditional Timber Framing excels at using lesser quality timber and, we feel, offers a more attractive Timber Frame for that.

Timber Framing can be created using timbers that are grown relatively local to us. The second and third growth forests that surround us can provide, sustainably, timbers for generations to come. Why ship timber 3000 miles? We personally believe that the Oak grown close by here is stronger, more attractive and overall better suited to Timber Framing than any other available timber. That said, these timber are not "clear" or "select" grades. They will have knots and other grain characteristics that make them so beautiful. We look at this as a good thing!

Now, onto moisture content. As we begin discussing moisture content we will be swinging back into the grade issue from time to time. Unfortunately, trying to regulate un-natural drying processes we need to keep an eye on the grade of the timber.

First let us stress that Timberworks does traditional Timber Framing. The joinery used, the methods and techniques have evolved by and for the use of unseasoned timbers. Yes, shrinkage and checking will occur. Part of the craftsmanship of fashioning the joinery is understanding these forces and effects, and working within those constraints. Timber Framing is meant for un-seasoned timbers.

Wouldn't it be great to fashion your timbers from dry materials to limit shrinkage and checking? Well, yes and no. The advantage of dry timbers might include stability, but checking will still be present. Timbers containing the center of the log (boxed heart) will check no matter how the drying occurs. Your seasoned timbers will still have checks. Stability alone is good, but how to get there?

The first option for dry timbers to consider is the salvage market. Hey! Let's just get some old timbers and use them! Sounds great...only thing is, unless these timbers are either still standing in a frame, or stored under roof so air can circulate around them, they are not likely to be stable. You will still have movement as the timbers acclimate to the new environment within your home. Add in the factors of dirt, insect damage, staining, dark or white-wash filled checks, old hardware and mis-matched sizes and finishes and they might not be so attractive anyway. The final blow might be cost. Salvage timbers can be very expensive, both to obtain and shape. While certainly a very "green" option, salvage timber is not for everyone unless you have access to some free timber or Timber Frame.

OK, let's move to the next item on the list...air drying. When do you want the frame? If we look at a fresh sawn timber, the rule-of-thumb states that it will dry at about 1" per year before it reaches equilibrium. This means that a timber with a small dimension of 6" will require 3 years of air drying. That is covered, "stickered" so that air can circulate. We need to ask again, you want your frame when? Air drying is simply just not feasible in most cases.

Finally comes forced drying. Conventional kiln drying processes just do not work with timbers. They only create "case-hardened" timbers as the outside cells collapse trapping large amounts of moisture deep in the timber. This makes them even more unstable than un-seasoned timbers and they really want to do crazy things when they are cut into! Not a good option. The only way to force-dry timbers is with Radio Frequency Kiln Drying (RFKD). Basically, a microwave in a vacuum. This process forces the moisture out from the inside of the timber. RFKD works best with softwoods, although hardwoods have been done. This limits the availability a little. Next, we need prime cuts to put into the vacuum chamber. Lesser grades dry unevenly and can fail. So we need Old Growth, and more "clear" grades. More costs and environmental consequences. Once the timbers come out of the chamber, we need to re-size them because they are no longer to size or square. Well, fire up the bandsaw and cut them to final size. More costs, more waste. Did we mention the costs just for the RFKD process too? All this adds up to a hefty sum, not being very "green" and can produce timbers that are hard to work. Is it worth it? That needs to be a personal decision for you, but, no really, we have been working with un-seasoned timbers for thirty years!