Friday, September 30, 2005
It's all down
It's been a long summer. After nearly 20 working visits to the barn site, and a few trips to Raccoon Creek to prepare for and unload wood from the trucks, it is all down to the ground.
On Tuesday we arrived at the site with a crew of two experienced in taking down barns and an enormous crane that could be raised to about 90 feet and its operator.
The crane was able to lift small and large sections from any part of the barn, all from the same spot. (Remember, the barn was 60 by 54 feet.) It had a "basket" that could lift two men to anywhere on the barn and provided ample space to work without getting in each others' way.
It was interesting to see a few of the crane's safety features. For example, if the hook was raised too high, before jamming in the top pulley, it lifted a weight, which took tension off a switch, which shut off the winch that lifted the hook. Also, if the weight on the hook and the angle of the crane together threatened to tilt the truck, the boom would stop until more cable was played out and it was lifted higher to reduce the angular force, or until some weight was removed.
The process was to lift us to a spot, attach a strong strap to one or more barn parts, remove the pins and nails, loosen the part as best we could, then set the basket down to let us out, attach the strap to the crane's hook, and lift the piece or section off the barn and place it on the ground where we could disassemble it.
Sometimes the lift was a single piece, like one of the stringers attaching two posts together longways at the top of the barn.
Other lifts were two to eight posts and beams that were tightly connected and more easily came down as one unit. There might even be a few knee braces included in the unit.
One mistake we made was not being careful to lay the units down the "right way," meaning with the correct side up to allow us to knock pins out from the top as the sections lay on the ground. We set many of the units down the "wrong way" and lost lots of time later taking them apart.
For each connection, we first tried to pound out the pin and "wiggle" the smaller part's tenon out of the mortise in the larger part. This wiggling wasn't as simple as it sounds. Many of the connections were still very tight after 140 years. We use a long 4X4 to pry and push the beam left and right as someone else inserted a wrecking bar, rock, wedge or board into the crack between the parts. At each change of direction, the crack opened up more and the a larger wedge could be inserted until the beam finally disconnected. It took two people to lift a typical beam, so this wiggling process took some time. Sometimes we were able to pound the pieces apart, but not often.
If knocking out the pin proved impossible, because it was too tight, had bent or broken inside the connection over the years, or the connection was wrong side up, we used a drill to core the pin holding the tenon in the mortise before using the "wiggle method" described above to separate the parts. Often the drill left what can best be described as a wooden straw inside the hole because the drill was just a tiny bit smaller than the pin or because the course of the drill missed part of the pin on the inside. In these cases we had to drill again (and sometimes again) to remove all the pin.
The last resort was to saw off the tenon. We tried to reserve this approach for beams with tenons that had already rotted away and would not be reusable. These beams will be used by attaching them to their posts with strong angular steel plates.
Some of the dismantling on the ground was done on Tuesday and Wednesday by two of us - enough for a truck load of beams. On Friday three of us worked nine hours and another for the last three to take apart every useful post, beam and knee brace. As it was getting too dark to work, the last pieces came apart and we loaded the generator to return it to the rental site.
A very tired crew drove back north in the dark. When we left the site looked like a giant game of pick up sticks.
Our selective logging friend was to return on Saturday to load all the useful parts onto his large truck and a long trailer for transport to Raccoon Creek. On Sunday we will meet the trucks and stack all the wood better to protect it for the winter.
I'll post lots of barn pictures on the web site next week.
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1 comment:
do you know the dimension of the posts?
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