Fitting together the timbers for a whole tree, forked timber frame house is a very creative process that involves a good grasp of geometry and physics in the bargain.
This week the three exterior porch pillars were set in place, and it was fascinating to watch. For each of the three bents that form the timber frame for our house, there were four posts that were fitted and attached with relative “ease” while the timbers were all lying on the newly–poured and very level concrete floor of the house. (see my post Up, Up and Away! Raising the timber Frame Bents at Underhill House ) With this arrangement, they could all be blocked and shimmed to precise positions, and they could be moved about on rolling carts. The end result was an incredibly quick timber frame raising last Wednesday, with each of the 12 posts fitting neatly on their assigned pins.
But this process did not include the porch pillars. Each bent required one more post that needed to be placed on its own concrete foundation in order to hold up the outside edge of our 8 foot wide porch that runs along the west wall of the house. We expect to eat many a summer meal and watch a ton of great sunsets from this porch. If it didn’t make the place sound like a retirement home, we might have called our house Sunset Acres because of the year-round front row seat we have for the setting sun.
These last three posts had to be fitted while hanging in the air, hoisted into position with a block and tackle device consisting of two pulleys threaded with rope. It’s a tried-and-true system used to lift heavy loads with considerable mechanical advantage.
Once one of the posts was in rough position, it was strapped to its beam with the come-along winch – this is a mechanical device that consists of a lever and ratchets that can adjust the slack or tension in the strap. The ratchet locks the strap in place, acting like a brake.
It took four of us to hoist the first post into position, but after that the ratchet winch could move it up and down as needed.
The top joints were final-finished from the top of a ladder using the chainsaw blade on an angle grinder. Prairie once wryly described this marriage of angle grinder and chainsaw as the union of two of the most dangerous tools known to man.
Using them from one rung shy of full extension of the 24 foot ladder did not improve the safety profile for this custom shaping. But each one was beautifully finished off by Prairie and Michael, and then a hole was drilled in the bottom of the post and it was set down on a steel pin to anchor the pillar.
When the first pillar was in place, Prairie, Michael and Doug sat down next to it and talked about what worked well, and what didn’t before tackling the next pillar.
This pillar will be by our main entrance and will greet guests as they enter. I have loved processing this timber every step of the way, from peeling to grinding, sanding and staining. It has a sinuous, sculptural, muscular beauty.
The middle porch pillar went up last. When it was hoisted into place, it became apparent that it would fit the contours of the beam it was meeting much better if it were spun 180 degrees, so down it came, only to go back up with a twist. That allowed the crew to take advantage of the natural crotch between two branches to bond with the beam.
Every step of the way, Prairie and Michael were moving calmly and deliberately, and taking every precaution. They ended up fitting each one perfectly.
Prairie said that putting up these pillars was probably the most complicated process yet in building Underhill House. But when it was done, it also gave him the most satisfaction. He said he took the most pleasure from the process of working collaboratively. Everyone who worked on it, Prairie and Michael with help from Bryan, Brad and Doug contributed to the strategy of how to hoist and fit these pillars into place.
I love the way they look and knowing they were placed through the artistry and intelligence of our great crew makes me love them even more. Because they are sitting outside of the house, they are stained a dark, bark-like color to fit in more naturally with the trees around them.
As Mister Natural would say, another job well done.
Categories: Eco architecture, Underhill House
They look a bit like David and Goliath sling shots. Very strong and sturdy.. Looks like Fun.
Yes, they do, don’t they. It’s no coincidence that both sling shots and these timbers are making use of the same inate strength of forked branches.
Della’s grant application for a second round of testing the strength of forked tree timbers has been approved, and the U.S. Forest Product Lab will soon be providing more scientific data on this subject.
I’m amazed at what goes in to building a house like this. It seems like you work around the wood, rather than making the wood work around you, if you know what I mean.
You’ve got that exactly right, Lorijo.
Or maybe we are working with the wood.
The crew and we have spent countless hours through the process of selecting, felling, peeling, shaping, sanding, painting or staining and then fitting the pieces together.
When we turned one of the porch posts 180 degrees, we ended up flipping a branch that would have extended out and probably been a hanger for a wind chime into the porch, and now it will probably be part of the support for a built in table.
It is a very organic way to build.
And everyone on the crew contributes ideas, which is very cool. One of the crew is a musician, and two of them are artists, several are master carpenters, and all these skills and insights keep the pot bubbling.
We are following a specific plan and must always be thinking several steps ahead in terms of insulation, electric wiring, pluming, ventilation and the like. But new ideas keep perculating out of the process every week.