This image is one in a series documenting the installation of the Equipment Barn Roof header plates: The roof truss-headers are the structural elements that secure the roof trusses to the building as well as transfer the weight load of the roof to the posts. The headers are subject to some the of the highest stresses of any element of the structure. As such, after the posts themselves, they are the beefiest lumber elements in the Equipment Barn. Constructed of #2 2x10, there is a header beam on each side of the 5x5 posts along the 56' walls. Therefore each roof truss sits on four of these 2x10's. Installation was achieved using a laser level to insure that all the headers were perfectly level across the building, A nail gun was used to tack the 2x10's to the posts. After initial placement a drill was then used to drill holes thru the headers and posts to allow for 1/2" diameter 10"-long carriage bolts that bear the attachment shear of the roof weight. Once the holes were drilled, relief holes were also drilled on the outside headers at each post to allow the bolt head to be below the outer plane of the header board. This was to get the bolt head out of the way when the wall is eventually covered in sheet metal siding. Each header/post junction received two carriage bolts, except where two header boards met at a post, in which case 4 bolts were placed thru the post. The bolts were outfitted with large flat washers to spread the torque of the nuts and bolt heads across several square inches of the header lumber. Wrenches were used to insure a high torque connection. At the ends of the building, the headers were trimmed off 1/5 inches past the end posts. This creates a shelf that the end roof trusses which will sit on against the outside North and South end wall posts.

Di, Jana and I sat in a guided punt on the Cam. The legend goes that Isaac Newton designed this bridge so that it didn't need any joins/bolts in construction. Some curious Cambridge students took it apart to see how it worked then couldn't put it back together again. And that's why there are joins today. The legend is false, of course. Newton didn't design it, it was William Etheridge. It is true, though, that the bolts don't carry any wait. They're there to resist the shear stress from wind, for example.