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October 31, 2010

Topping Out

topping out

We had been looking forward to “topping out” the frame for a long time, but when the day finally came – October 23rd – we hardly had the time (or energy) to pause for celebration. At 3:30 pm, a small hemlock graced the rafter peak in full sunshine, in thanks to the forest for providing the material for this shelter.

topping out

Before achieving that moment, we’d put in long, exhausting sessions cutting and installing the final frame members that form the building’s rafters. The rafters are made up of twelve sets of three pieces each – a pair that join at the peak and the long section that slopes down to the back of the building. The rafters were cut from 4x6 timber with a pegged half-lap joint at the peak, a stepped section to fit the rafter seat at the top plate, and a two-foot tail to extend the roof past the edge of the building.

We spent a total of 26 hours to cut the rafters in a very efficient process that took full advantage of the many years that Marion and I have worked together. If I had taken to shaping those 36 timbers on my own I’d have been knee deep in snow before they were complete.

topping out

When it was time to install the rafters we had to clear snow from the loft floor. In the photo above, Marion works to clear the ice from the rafter seats in the top plates.

topping out

The rafters spanning the loft were assembled in place. On a larger building, however, these would have been assembled on the ground, then hoisted into position.

topping out

Once the half-lapped joints at the peak had been clamped, drilled, and pegged, I marked the rafters above the seats for the pegs that would hold them in place.

topping out

Holes were drilled ten inches deep, through each rafter and into the top plate.

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Each connection received one oak peg, driven snuggly into the joint.

topping out 

The photo above shows the pegged joints at the peak.

topping out 

With the rafters in place over the loft, the building begins to show its final form.

topping out

Another lap joint forms the intersection of the gable rafter and the 14-foot timber that slopes to the rear of the building. Above, a gable rafter can be seen housed in its seat before the final rafter section is laid in place.

topping out

With the last rafter pegged, our frame is complete. We topped out on a glorious late October afternoon with blue skies and temperatures in the 50’s. When the moment finally arrived, I rushed to find a small hemlock and affix it to the peak before the sun dipped below the ridge.

topping out 

We took several shots of our completed frame. To get the images, I positioned the camera atop a step-ladder, pressed the self-timer button, then raced for the building. After each sprint I wished for an option to set the timer interval at something longer than the 10 seconds I was allowed to get myself in position, gasp, compose, then smile. (Marion’s smile came easily as she enjoyed the many outtakes that were spared from this publication.)   

October 24, 2010

Light At The End Of The Trunnel

pegs

TRUNNEL: (from “treenail”) A wooden peg typically ¾-in. dia. or larger, usually of oak or other tough hardwood, formerly riven and shaved, now usually turned, and used to fasten timber joints, particularly the mortise and tenon joint.


The advent of the inexpensive wire nail in the latter-1800’s, coupled with the desire to reduce building costs by employing relatively unskilled labor, led to the development of stud (“balloon frame”) construction in the decades following the Civil War. “Two by” studded frames have proliferated since the latter-1800’s and the building technique continues to be the dominant framing method used today. (Prior to the development of cheap, soft steel and the advent of the wire nail in the 1880’s, nails had been cut (square nails) - beginning around circa 1790 - or hand wrought - previous to 1800.)

Traditional timber framing relies on mortise and tenon joinery fixed together by wooden pegs. (Although much of today’s so-called post and beam construction uses steel plates and bolts to attach the framing members.) For our equipment shed we used 1-inch diameter oak pegs throughout. Rather than cut our own pegs with a drawknife, we relied on the quality work of Scott Northcutt in Walpole, New Hampshire.

In the photo above, the drilled tenon is visible with pegs inserted in the mortise cheek. The photo opportunity came out of a mistake that required us to drive the top plate up off the posts in order to reverse a brace that had been installed backward. (With many hands on the barn during the raising, I hadn’t noticed that a brace, which had dropped out of its mortises at one point, had been turned around when it was reinserted.)

pegs

During the next work session following the raising, we pulled the top plates tight to the post tops (again using come-alongs and a commander), then drilled and pegged the joints.

pegs

Looking up at the frame members (here, the post, braces, bent girt, and top plate), it’s easy to understand the aesthetic appeal of a timber frame.

pegs

In the photo above, a post, floor joists and post braces are fitted and pegged in their final form.

pegs

We installed a series of housed half-lapped wall girts on the back and sides of the frame near the base of the posts.

pegs

Two more wall girts were installed on the sides, midway between the post bottom and the loft floor.

pegs

It took a full day to install the loft sub-flooring due to the many cuts that had to be made around the posts and braces. We finished in near total darkness, thankful for the LED light on my skillsaw that illuminated the cutting line as I trimmed the ends of the installed flooring to the final dimension.

 

October 21, 2010

Barn Raising - Part 2

raising

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.

raising

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.

raising

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.

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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.

raising

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.

raising

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.

raising

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.

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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.

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The top plates were lifted to the loft for assembly on the long flat surface provided by the frame.

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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.

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Once the blades on the scarf joint were engaged, we drove the pieces home and checked the assembled dimensions.

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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.

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In the photo above, Ed checks the measurement while the come-along draws the frame together.

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Mom and Molly (Ed’s faithful golden retriever) looked on to see how it all would work.

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Evan does some final tweaking with the commander and we’re ready to lift the plate to the top of the posts.

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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 . . .

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With four post tenons and six braces all inserted, we drove the top plate home.

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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.

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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.

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October 15, 2010

Barn Raising - Part 1

Raising

I was unable to contain my anxiety on the morning (September 26) that we prepared to finally raise the bents for the equipment shed. I’d slept poorly the night before. There were too many unknowns leading into this event – all new territory in my building experience.

raising

On the previous afternoon, Marion and I had been playing horseshoes above the barn site. Looking down at the bents lying on the ground, Marion had commented about it being the last day for perhaps hundreds of years that the spot would be without a building. It struck me that we were about to alter the landscape for generations to come. Given that responsibility, I want to make certain that we get it right.

We’d invited Marion’s brother and his wife to help us lift. I’d been hesitant to invite more friends and family because of my reluctance to ask them to drive 80 miles just to help stand 4 timber bents up. More than likely, I was also struggling with my nagging fear of failure. I didn’t want a large audience witnessing some previously hidden fatal flaw in my work. The demons inside hadn’t slept the night before, either.

raising

Prior to Toad and Cat’s noontime arrival I enlisted the help of my buddy John (Deere) to do the initial lift. Machines, however, are not always the best tool for such delicate work. While they may have the muscle, there is no substitute for the subtle touch of human hands. For the final heave ho, the four of us provided the effort.

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One . . . Two . . . Three . . . PUSH!

The heavy bents went up with relatively little strain.

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We had blocked the tops of the foundation piers in a way that allowed the posts to stand above the steel anchor pins. The posts had been drilled to accept the pins. The most challenging part of the procedure was the removal of the blocks and lowering the posts to their final elevation. I found that the steel cage on the tractor’s fork lift fit perfectly between the braces and I was able to lift with the machine while Marion, Toad, and Cat positioned the posts above the pins. Once in place, I braced each bent with 2x4’s and we moved on to the next.

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Three hours later we broke out the food and cold beer to celebrate a successful part one of raising the equipment shed. Finally (and suddenly), the building began to take form.

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We lingered past sunset on that late September day, admiring how precisely everything had come into alignment. I moved from vantage point to vantage point, eying down the posts and beams. All were level and true. The care we’d taken in the work of the previous year had begun showing its reward. I allowed my demons some time off. I slept well that night.