Roof Truss Step Bottom Chord

The bottom chord is the bottom horizontal or inclined member of a truss.

Roof truss step bottom chord.

This is where you will make a bottom chord. The span in short is the length of the bottom of the truss. One truss cut only at the third point. To keep the plywood from cupping under the load 2x4 squash blocks were to be inserted between the top and bottom chords.

For example if a truss has a span of 26 then the bottom chord can be built with two boards 16 and 10 which allows for no scrap and waste and is the most efficient for price savings. It will attach to the bottom of each end of the rafters with a straight length of wood. The bottom chord therefore carries combined stress of both tension and bending of the truss. Flat the most economical flat truss for a roof is provided when the depth of the truss in inches is approximately equal to 7 of the span in inches.

Some spans have a lower rate per foot than others. The adjoining trusses appear slightly out of plain. The bottom chord establishes the lower edge of a truss. Most economical when the difference in slope between the top and bottom chords is at least 3 12 or the bottom chord pitch is no more than half the top chord pitch.

It has been cut adjacent to a node point. A domestic roof engineered truss has had the bottom cord cut to install an attic access hatch door. To reinforce the ends of the trusses 3 4 inch plywood gussets were to be attached to both sides of each truss with 10d nails 3 inches on center on all chords.