Roof Truss Step Bottom Chord

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

Roof truss step bottom chord.

It will attach to the bottom of each end of the rafters with a straight length of wood. 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. This is where you will make a bottom chord. Some spans have a lower rate per foot than others.

Create a bottom chord while you have established the angle of the trusses with your rafter pieces and cut them in the necessary lengths they still need more support to finish the structure. 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. The bottom chord therefore carries combined stress of both tension and bending of the truss. The node gang nail at the cut point looks in distress and has partially pulled out.

To keep the plywood from cupping under the load 2x4 squash blocks were to be inserted between the top and bottom chords. The bottom chord is also called a scissors truss. The bottom chord establishes the lower edge of a truss. The adjoining trusses appear slightly out of plain.

One truss cut only at the third point. 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. A domestic roof engineered truss has had the bottom cord cut to install an attic access hatch door.