Erecting a Pole Building

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Sound short and simple? Absolutely.

Second-Story joists

If you are planning a building with a second floor, the floor joists are the next step. The joists are 2 X 8's or 2 X 10's sitting on the top plate, running from one side of the building to the other. If the building is too wide to run a solid joist, there should be a supporting plate running down the middle or wherever the joist joints will be (Fig. 14).

The joists should be on 16" centers. Toenail them into the top plate with 16d common nails. (You may want to cut angles on the ends of your joists so they won't stick up above the rafters and have to be cut later.)

When the joists are in place, you can put on your decking, using at least I/2" CDX plywood panels. To start the plywood, strike a line 1 ' in from the edge of the rafters. This allows room for the rafters to rest on the top plate. Nail the decking, staggering the joints as you go (Fig. 15).

Rafters and Trusses

Rafter and truss are the terms most commonly given to the structural framework of the roof. A rafter is one of the parallel beams that support a roof, and a truss is an assembled rigid framework. We will discuss trusses and their setting, and then the laying out, building, and setting of your own rafters.

Factory trusses have gained much popularity in the past few years, for a number of reasons. Strength is one selling point; they are engineer-designed, constructed with heavy metal gussets, andbecause they are mass-produced-they are uniform. From the self builder's point of view, simplicity would have to be the shining attribute of trusses. It is much easier to swing a truss into place and secure it than to figure, cut, and erect rafters. Trusses can be bought from many local lumber mills in a variety of styles.

The first truss set is known as the dead truss; it sits along the outside wall against a pole (Fig. 16). It is important that the dead truss be level, as the rest of the trusses will be set using it as a guide. When using purlins on your roof, you may space your truss 4' on center unless you have a very low roof pitch or expect heavy snow loads. For other applications use a 2' center. Mark on the top plate the location of the truss, 4' from the outside of one to the inside of another (Fig. 17). Place one end of the truss on the top plate, then walk the other end up, leaving the truss hanging inverted between the walls. To right the truss, push it up with a 2 X 4 wedged in the peak. When the bottom of the truss is in place and nailed to the top plate, measure from the dead truss near the peak the same outside-inside measurement used at the plates. Anchor the truss in place, using temporary bracing running from the dead truss (Fig. 18). Repeat this procedure until all your trusses are set. Keep in mind that as you get to the end of the building, you will run out of space to swing the last couple of rafters up into place, so plan ahead by raising the last few all at once and setting them later. Be sure, too, that the overhang of the truss remains the same all the way down the building; it may be necessary to push or pull the walls just a little.

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