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4 a temporary floor of loose boards is laid on the joists, so that the
, can move about freely while raising the trusses into place.
J Jans will show exactly how to cut and put the first truss together —
look like Illustration I , page 26. When this first truss is completed,
laid out on the floor, and all the other trusses may then be built
exactly like it, one on top of the other, thus insuring absolute accuracy.
When all the trusses necessary have been finished, the first truss is placed
in position at one end of the barn.
This is usually done by placing the feet of the truss at the places where
they are to rest when in position ; with the top of the truss toward the center
of the barn. Blocks are then spiked to the joists at the proper points, so as
to keep the feet of the truss in place while being raised ; the feet of the truss
resting against these blocks and pivoting on them.
A gin pole (shown in Illustration 3) is erected at the end of the barn
in the center, leaning at an angle of about 45 degrees toward the center of
the barn ; a block and tackle is rigged, the rope passing over the gin pole and
attached to the upper parts of the truss. A horse or team is hitched to the
block and tackle, and the truss quickly raised to position.
A gang of men can do the same work, but the horse or team is cheaper.
A few men with guy ropes are necessary, to steady the truss while being raised.
