Barn Raising - Part 2
BENT: An assemblage of timbers perpendicular to the ridge, usually the crossframe of a building, assembled on the ground and then reared up into position.
With the four bents of the equipment shed standing as a result of the previous weekend’s effort, we set aside the weekend of October 2nd for installing the floor joists and top plates.
JOIST: Relatively small timber, usually spaced regularly in sets to support a floor or ceiling.
GIRT: Horizontal timber joining wall posts at a level somewhere between sill and plate. A wall girt runs parallel to the ridge, a bent girt perpendicular; either can support the edge of a floor frame.
COMMANDER: A large wooden mallet typically weighing 15 to 30 lbs.
The joinery I chose for the floor joists in the loft required that the joists be installed before locking the frame together with the top plates. In order to put the joists in place, we had to lean each bent slightly, insert the joist tenons into the bent girts, then bring the assembly back together with the use of come-alongs (hand-levered winches) and a commander (which, in our case, consisted of a chunk of wood driven by a maul).
To provide support for the ends of the joists before they were inserted into the bent girt mortises, I installed 2x4’s spanning the posts below the girts.
With one bent leaned and braced, we inserted an end of the joists into the opposite bent girt and rested the other end on the 2x4 support.
Once all the joist tenon ends were aligned and inserted into the corresponding mortises in the bent girts, it was time to draw the assembly together. I wanted to be sure and get some good photos of this joint since the very important subtleties of its diminished haunch become hidden in the completed frame.
By the end of the day Saturday (October 2nd), we had all 15 loft floor joists installed and the bent posts standing true, awaiting the final step that would lock together the frame – installation of the top plates and braces that run perpendicular to the bents.
TOP PLATE: The most important longitudinal timber in a frame. It ties the bents together at their tops and simultaneously stiffens and connects the wall and roof planes while providing a base for the rafters.
John (Deere) is a big help when it comes to transporting timbers – especially the 20-footers that make up the top plates.
Before our work crew arrived at noon on Sunday (October 3rd), I test fitted the braces and made the final adjustments with chisel and plane.
Once the braces were tested and adjusted for fit, I labeled them all and laid them along the floor joists adjacent to the locations where they’d be installed in the frame.
At noon, the barn raising crew began arriving. First, my mom and dad showed up with some home cooking to feed us all. Next, Ed and his friend Kim pulled in with bread and cookies to share.
My nephews, Nathan and Evan, arrived soon after. Their youthful muscles would be key to getting the top plates in place.
The top plates were lifted to the loft for assembly on the long flat surface provided by the frame.
The top plates consist of two timbers connected with a scarf joint to make up the required 30-foot length. Many variations of scarf joints have been used in timber frames over the centuries. I chose to use what is known as a bladed scarf for this project.
Once the blades on the scarf joint were engaged, we drove the pieces home and checked the assembled dimensions.
With the plate driven together and pegged, we did a final check on the distance between posts, using come-alongs to bring them into precise alignment at 10-foot centers.
As I’ve noted before, timber framing does not allow the same tolerance for error as contemporary stud frame construction. All mortises must align perfectly with corresponding tenons in order for the frame to fit together. In the case of our equipment shed top plates, four post tenons and six brace tenons would be simultaneously fitted in a single operation.
In the photo above, Ed checks the measurement while the come-along draws the frame together.
Mom and Molly (Ed’s faithful golden retriever) looked on to see how it all would work.
Evan does some final tweaking with the commander and we’re ready to lift the plate to the top of the posts.
Four of us were positioned along the top plate, ready to lift, while Marion and Kim waited below to insert the braces into their mortises.
One, two, three, and UP . . .
With four post tenons and six braces all inserted, we drove the top plate home.
After three hours we had three top plates and eighteen braces fitted atop the posts, locking the frame together. With great appreciation for the help of family and friends, we gathered for a meal and celebrated a major milestone in the project.
After our guests had departed I found myself transfixed by the simple beauty of the frame. Once again, I stayed in the orchard past sunset, savoring the satisfaction of a moment when hard work pays out its reward.