Well, the long-awaited barn raising day finally arrived this past Saturday, and my family in the area arrived to help. Wrestling eight 14-foot rafters was definitely a portion of the barn build that I could not accomplish alone. Of course, like any good barn raising, the family brought food, we grilled out, and we made a day of it.
The first order of business was to explain to my “crew” what we would be doing. The barn’s roof is supported by reciprocal frame rafters, a term coined in the 80s to describe roofs whose support members interlock with each other to create a self-supporting strucutre, like a kind of arch. It takes a few moments to wrap one’s head around how it all works, so I had a small-scale model to demonstrate the concept:
After that, it was on to portaging the rafter timbers to the barn site. As for seemingly everything related to this project, the motto is: “If it’s heavy, it must go uphill.”
Once all the rafters were staged, we assembled the “charlie,” the support tripod which holds the first and subsequent rafters until they support themselves:
After that, we started the show, laying the first rafter over the beam and onto the charlie. The base of the rafter (the eave side) had a pre-drilled hole about 24” up that slipped over the rebar pin from each post.
As each rafter is laid up, they have to be angled correctly to make the central circle to support the other rafters. This requires that each rafter be offset a standard distance from the central point. I chose an 18” offset. My daughter Eleanor was tasked with the “jumper,” an extendable pole that she lined up with the offset mark to give us a target to aim the rafter. She trued the pole to vertical with a level to make sure the end 12 feet above wasn’t out of line than the mark on the beam.
And here’s my 7-year old, helping as well:
Once each rafter is laid up and “aimed,” I marked where it crossed the rafter beneath it. Then I moved the top rafter aside and chiseled out an angled channel for the rafter to lie in. Once that was accomplished, I moved the rafter back into place, re-aligned it, then drove a six-inch nail beside the top rafter, just “downhill” of it into the rafter below to secure it from slipping down. I also lashed the rafter in place, because I’m a “belt-and-suspenders” kind of guy. Then Eleanor “jumped” her pole to the next offset mark, and the next rafter was passed up.
Finally, all eight rafters were in place and (theoretically) ready to support their own weight. All the Internet tutorials said to expect the rafters to creak and settle several inches as they found their place and took up the weight. So, we cleared everyone out of the area, and my brother-in-law, nephew, and I manned the three legs of the charlie and got ready to pull the legs apart and drop the charlie away from the rafters.
We all held our breath, said a little prayer, and pulled the charlie away.
Nothing happened. No creaks, no movement. Nothing. Just eight rafters blithely supporting themselves 11 feet in the air.
The central circle wasn’t as symmetrical as I would have liked —chalk that up to my inexperience with this kind of roof—but I suspect the goats won’t be bothered by asmymmetry. I climbed up to test with my weight, and I didn’t die:
Next up: Attaching the purlins and starting to put the roof on!