By Bert Sarkinnen, Arrow Timber Framing
My first experience with Timberline Lodge on the southern slopes of Mount Hood in Oregon was an awe-inspiring visit in 2007. My family came for a snowboarding outing \ that winter, and it was five years after I had first fallen in love with the craft of timber framing.
Before hitting the slopes, I spent some time admiring the beauty of the lodge’s architecture. Timberline has the classic Civilian Conservation Corps architectural touches which were a trademark for many projects here in the Northwest. But Timberline Lodge also has unique touches, such as how its footprint and silhouette allow it to nestle into the mountainside. To me, everything about it then seemed picture perfect: the snow on the roof, the fading sunlight, and Mt. Hood in the background.
I ended up coming off the ski hill early that evening for two reasons. First, I wanted to have time to hang out in the lodge and absorb as much of the atmosphere as I could. Second, I was worn out! My boys thought I was crazy, but I declined to use the ski lift. That gave me a good workout and prevented me from attempting escalating stunts that could result in serious injury. I figured my downhill runs would be pretty safe and mellow after hoofing it up the hill.
Entering the lodge itself was a bit odd. A corrugated metal roof creates a tunnel, which keeps the snow off the main entry steps. This is obviously a seasonal stopgap, and I suppose any design, no matter how stunning, leaves room for improvement. But from there on, the feeling is spectacular! Unbelievably huge, arched, entry beams and timbers, massive stone fireplaces, wide plank flooring. Trying to calculate the total man-hours required to complete the project made my head spin. The main attraction in the heart of the lodge is the hexagonal lounge: it is roughly 60 feet across with a huge stone fireplace in the center. Six hexagonal timber posts support a wraparound balcony and continue up to support the roof. These gargantuan posts, each approximately 3 feet across, were shaped and hewn back in the 1930s for the price-gouging sum of $150 apiece!
After touring the entire area, I chose a couch on the balcony and settled in with my chocolate, book, and tea. I tried to read but the atmosphere was simply too attractive and distracting to concentrate. I realized I wanted to construct a project on the same scale someday. Little did I know then that my company, Arrow Timber Framing, would be building a smaller project for the Timberline Lodge in the near future.
- Carving traditional pockets for joinery to eliminate bright metal clips;
- adding beams to provide better support for the hip and common rafters;
- upgrading the solar platform deck;
- incorporating copper caps for the exposed rafter rails;
- fully supporting the tension ring at the corners and improving the plate connection; and
- replacing a pressure-treated fascia board with stained fir to improve the aesthetic and avoid an unsightly color clash with the rest of the structure.
The gazebo is tall and I worried about it being erected crookedly. I didn’t want a Northwest version of the leaning Tower of Pisa! The gazebo derived its lateral strength from four massive metal plates embedded in the concrete foundation. The four hexagonal wood posts were then inserted into collars, which protruded 3′ above the foundation. Those base plates would have to be set with extreme accuracy to ensure that a 14′ post, extended from a 3′ high tube, would remain true.
My worries were alleviated when I hit upon the idea of pre-tensioning the posts. I would intentionally install the posts a little crooked in opposing directions. Then we could simply push the posts outward away from each other! The structure would have a much higher probability of standing true and would be even stronger.
Originally we had planned to stage the whole roof structure on the ground and call in a crane to lift it into place. Two problems became apparent. First, the area of usable space was very small. Second, a crane of that size needs smooth access with no height changes in the approach: it can’t even hop a curb! Instead, I hired a friend who is a talented forklift driver, not only with the physical controls but more importantly with forklift creative logistics and uses. There were other hurdles, but the process went mostly as planned.
In talking with the Forest Service engineers about timber framing, a little secret was revealed. According to calculations, Timberline Lodge does not perform very well in lateral load resistance. Its ability to shoulder snow loads is off the charts, but its ability to resist toppling over is surprisingly low! The engineers shared with me two things that explain why so many older timber frame structures, including the lodge, have stood the test of time even when knee braces in some structures seem inadequate:
1. The sheer weight and mass of the heavy structure. In today’s world of light construction, the mass of a structure is given no value in calculations to quantify resistance to lateral movement.
2. Inherently strong geometric shapes and synergy. Calculating a structure’s strength on a flat plane is easy. Doing so in a three-dimensional plane is a lot tougher; in order to perform such a calculation, one would have to evaluate the entire structure’s synergetic strength. It would also need to take into account how one portion of the structure could not collapse without resistance from adjoining portions.
Another fact attesting to Timberline’s true strength is obvious: Storm after storm has swept over the mountain in the last 70 years and Timberline Lodge is still standing tall.
I am glad the new Timberline signs were built by Arrow Timber Framing, as a tribute to the bygone craftsmen who constructed the Timberline Lodge itself. The lodge is a gorgeous place. If you have not been there, book a night or a ski visit. You will see the craft on a grand scale, absorb its weight, and leave with a lasting impression of a magnificent timber atmosphere.