Trusses arrived Friday!
I took a half day off, and got started about 1:30. I managed to get the first 5 trusses set before reinforcements arrived in the form of two of my friends. With their help, and in spite of a couple thunderstorms that blew through, we managed to be finished by 8:00.
There are a few tricks to setting trusses by yourself. The first thing you need is bracing at the end where the first truss will be set. You need 3 vertical members from the bottom of the wall to the top of the truss at that place. Technically, they should all be braced to the ground; I only braced the middle one.
Next, you need some "helpers" at the end where the trusses are laying on the ground. There needs to be something sticking out from both ends of that wall to support the trusses at the top of the wall. In my case, I had the breezeway beam at the left end, and I fabricated a ramp with 4 strategically located stops. These stops were little wedges of 2x4s at shoulder height, press height, halfway between press height ant the top of the wall, and at the top.
Something new with this batch of trusses (it's been 10 years for me), is that each one was nailed to the next with a little sinker nail. Just enough to keep them from sliding across each other when you break the straps.
I didn't like the horizontal weakness of the bottom chord, so I nailed a 4 foot piece of 2x4 across that splice so that the truss wouldn't break when laying horizontal across the walls. I also nailed a couple blocks sticking up from the ends of each truss, so that they couldn't slide off the walls while I was moving them.
Now, it is time for some physical labor. Drag the truss over to the wall where it starts. Grab the first end about 4 feet from the end, and shove it up the wall. Keep going up until you can catch your helper, and go to the other end. Push that end up also, catching the stops on the helper at that end. At this point, you also need to make sure that the first end doesn't slide downhill off _that_ helper. At this point, you have a truss hanging upside down off the end of a wall.
In my case, the helpers were about 3 feet in from the end of the wall, which had the bottom chord of the truss sticking up enough for me to get a 2x4 under it an pry. It was fairly easy to pry the truss up and over so that it laid flat on top of the wall.
One way to proceed at this point is to have a temporary support wall down the middle, so that you can just slide the trusses to where they will be going. I skipped that step, and carefully slid the truss so that the top slid off the wall and it hung upside down. I then nailed a pre-cut block of 2x4 to the peak to catch the next truss. This is one of those things that we now take for granted, but wasn't possible before nail guns came in to common use.
At this point, it is simple to slide the truss down the wall to the other end of the building. You don't want to go too far at a time, though, or one end might fall off the wall while you are sliding the other end.
After the first truss, I cut blocks to go between the existing truss and the one being erected, to lay on top of the wall and stop the truss where it was supposed to go. I slid the truss up about 8 inches from these blocks, and then started the process of erecting it.
There needs to be a prop cut to the same length as the wall height. Swing the truss up with this prop, and stop when it is flat.
Next, you need a prop long enough to reach from where you can hold it, to the top of the erected truss. In this case (24 foot span, 6-1/2 foot height, 10-1/2 foot wall height), a 16 foot 2x4 was long enough to reach.
With single-handed truss setting, the most critical point is between when you get it up (from the floor), and when you nail it (at the top). If you get this wrong, the truss might fall, it might break into little pieces, and it might bust your head (or other body parts) in the process.
What I ended up doing to manage this aspect, was to use my little utility trailer. I would set the end of the prop on the trailer, slide a block up against it, and nail the block in place. My uneasiness at this process was slightly diminished by the wind blowing in a direction that would have held the trusses up if I hadn't done anything smart.
So, this part of the process looked like: Shove the truss up, nail a block to hold it, throw up the extension ladder, grab the nail gun, run up the ladder, nail the top of the truss. Then, at a bit less frantic pace, go adjust the truss to the string line ( just barely not touching the string; if you touch the string the trusses will gradually push out and you will have a nice convex bow to your facia line) Nail the truss to the wall, take off all the blocking you nailed to it, and remove the nails for reuse, and get ready to repeat.
Each truss need to be nailed to a 2x4 that runs from one end of the building to the other. This can start with a short piece from the start end. When these overlap, they need to have 3 trusses nailed in common, with 2 nails into each 2x4 in each truss. Also, there needs to be a diagonal brace crossing at least the first 4 trusses, nailed into each. I only just barely got these braces in place before the first thunderstorm blew through.
The other detail of truss setting, solo or with a crew, is bracing. There should be a run of 2x4s down each side of the roof with 2 nails into each truss, overlapping with at least 3 trusses nailed in common, in addition to the blocking at the peak. There should also be a diagonal brace for at least the first 4 trusses, with 2 nails into each.
By myself, it would not be finished yet. I had some volunteer labor to do today, and wouldn't have been able to finish until tomorrow. With the help of a couple friends, though, that stage is behind me.
Next up is to place the other beam for the breezeway, and put joists and rafters on that. Before that task, though, I need to use the scaffold I have in place to put the hurricane clips on the trusses in place.
