Wednesday, May 8, 2013

Chapter 13 - Peak Framing

Chapter 13 – Peak Framing
Now it was time for the truly exciting part of building my timber framed structure. This is the peak of the house, the highest point, and the place with the best view, the most wind and the longest trip to the floor! I spent some time at the tops of the queen posts before I started to get used to this elevated location. Evaluating the fit of the lower rafters at the tops of the queen posts was more to have a reason to be there than having any expectation that something might be wrong or need to be fixed or that any problem was even fixable. There were no joists to stand on or leap to and nothing overhead to steady my balance. The building of the peak was where all of the practice and experience would culminate in catastrophe or success.
Ridge Pole ground test
The first thing to decide was where to start. I started the loft level framing over the two outside bays and then connected the center bay timbers between them. I did that so that if the structure was out of plumb or square, I could make some adjustments in the center bay. Since I didn’t need to make any adjustments, this sequence didn’t seem necessary for the peak. Another consideration was that the peak assemblies were just a king post and a peak purlin, two legs and a crosspiece. This assembly would not stand solidly until the two upper rafters were attached to hold it up. The loft assemblies stood solidly without the lower rafters since they were four legged boxes. The biggest consideration though was the size of the assemblies involved. I felt more comfortable with the idea of starting with the smaller 8-foot wide assembly over the center bay rather than the 16-foot assemblies over the outside
50 mile/hour wind survivor
Furthermore, I reasoned that the outside structures would be easier to raise if the inside king posts were already in place and well secured. That way I would only have to worry about the outside king post and its peak purlin instead of two king posts and a peak purlin all at the same time.

Ignoring the height above the ground, and the fact that my raising equipment would need to be set up on top of the loft timbers, the peak assemblies should be easier to raise because the peak purlin is not as high as the loft and first floor cross beams. The peak purlin is attached to the top of the king posts that are only 7 feet tall instead of the 8 or 9-foot height of the loft and first floor cross beams attached to 10-foot tall posts. Though this is simply an artifact of the geometry, this shorter structure seemed a lot friendlier.

Once I had rationalized that raising the peak was going to be no big deal, I cut the parts. Since I wanted the peak to be a focal point, and one would be looking at it from two stories below, I made the braces a bit larger than the other braces. These braces are the same length and shape as the other braces but are an inch larger in the width and thickness. This slightly larger brace size makes the roof structure appear more solid and obvious. The king posts also appear slightly larger than the other posts because the tops where the rafters and peak purlin meet it are 10 inches wide instead of the 8-inch width of the queen posts. This extra width is actually there to accommodate the mortise for the peak purlin in the center of the face of the king post. I made the king posts from 8x10 timbers and ripped the bottom of the posts to form 8x8 posts leaving the 10-inch width at the top to accommodate the three mortises, two for the upper rafter ends on each side of the king post and one for the peak purlin on the face of the king post. Ripping an inch off the sides of an 8x10 timber is no easy task! I wanted the peak purlin to match the size of the other purlins that are 6x8 timbers. In order to create this size for the visible part of the peak purlin and have a pointed top edge, the peak purlins are made from 6x10 timbers. Ripping two 45 degree angles along the top of these timbers to form a straight point along the top edge of the timber is also not an easy task! From a practical point of view, this top pointed edge will never be seen and isn’t even necessary for attaching a roof, but I believe that sometimes the principal is more important than any practical considerations. I think of it as craftsmanship.
The next morning started out a bit windy and the idea of raising the next peak purlin and its post did not seem like a good plan. With every passing hour, the wind speed increased by about ten miles per hour. Before noon, the wind was roaring at about fifty miles per hour and was not likely to stop until dark. Panic set in. I had visions of two king post spear points sticking through the deck into the apartment. Worse, was the fact that the 1/4-inch hemp rope that I had used to support this structure was not only wimpy but the only rope that I had readily available. The only rope left was the 100 feet of block and tackle rope. If that wasn’t enough to strike terror into my heart, I realized that I was going to have to go up there in the gale and improve my guy lines with that block and tackle rope. Though I hated to do it, I also nailed braces to the king post and the beam that it was standing on. I was terrorized by wind gusts for the rest of the day. I’ll never know if the additional rope and braces were necessary or not, but I’ll never forget that windy Colorado day.
About six months later, only a few months after Linda had moved here, there was another windy Colorado day. Linda had just started nursing at the local hospital and was scheduled to work that day. She experienced the same sort of terror that I had not too long before and called the hospital declaring a “wind emergency”! Naturally, the local folk were a bit perplexed. The “Chinook winds” were a completely new experience for both of us; where we came from, they would be called a “Hurricane”!
The next day, my world was back to normal and I got back to work. Obviously, putting up another guy lined ridge purlin was not as good a plan as putting in the upper rafters that would hold up the already standing king posts. Since the upper rafters have the same joinery as the lower rafters and I had done this eight times before, I knew exactly where to move the gin pole to raise these four upper rafters. I remember from my previous career someone complaining that the trouble with engineers is that they are always changing things. Never content with “it works fine and is good enough”, the engineer in me was always changing how I did things, trying to find a better way. For this raising, I used two come-alongs strung end-to-end to reach from the top of the gin pole to the upper rafter lying on the loft level, instead of the block and tackle and a come-along arrangement. The advantage of omitting the block and tackle is that you don’t have to tie off the block and tackle rope to stop the raising process; you just quit cranking the come-along.
Moving the 100-pound, 18-foot long gin pole from bay to bay was difficult. I had to lay it down (gently) on the loft level, move it into the next bay and then stand it up again. I tried many ways of doing this too. It was easiest to untie the two back guy lines and use the front guy line to control the top, leaning it on some convenient frame part. From the bottom I slid it downward until it was ready to fall and then got above it and used the front guy line to lower it the rest of the way down. Standing it back up was the reverse of this process. The trick, of course is to reattach the back two guy lines before using the front one to stand it up. This was another reason to finish the center bay before moving on to the bay #3 raising.

There are no videos of the peak framing and few photos either. I don’t recall if the video camera died, or that I couldn’t find a good place to sit it, or the danger of working at this height made taking pictures at the same time seem kind of dumb, if I just got tired of the documentation thing, or if what was left to do was just a higher version of what was already documented.


On my 47th birthday, I had one more purlin to install to finish the frame. I was disappointed that Linda was not there for this momentous event. My friend, Carl, who had been visiting on a regular basis, was aware of my mood and took it upon himself to make this occasion more noteworthy. With excellent timing, a parade of neighbors and their dogs came down the driveway to help me celebrate, champagne and all! One member of the group even brought his video recorder and later gave me a tape of the event. I was touched by Carl’s thoughtfulness and the support of my neighbors.
Raising the second to last timber
My photograph collection is focused on the raising of the frame because, for me, this was the most interesting and challenging part of the project. One could almost think that the finished timbers were being delivered now and then, and I took pictures of raising them! Actually, for every timber-raising event, there were several weeks of timber cutting that never made it to film. There were 268 dovetails and 140 brace tenons and their 408 associated mortises to be cut - not mention a host of other mortise and tenon joints - all as close to identical as possible and incredibly boring to document. However, this joinery is crucial to the construction of a timber framed building. I’ll discuss the time-consuming and somewhat boring process of timber joinery cutting in the chapter called “Joinery”.

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