Roof Truss Chord

Closed open distinction is used in two ways to describe truss roofs.

Roof truss chord.

End trusses close in the end of a building and provide a nailing surface for the upper end wall or rigid sheathing. Box 177 la crescent mn 55947 507 895 8400. For example table 3 5 1 allows identical trusses to vary in span by as much as 1 2 in. The chord size and web configuration are determined by span load and spacing.

Finally there are the gussets that hold the framed truss together. These steel joints are needed to support the overall truss. It is most often used for roof construction. In span and 1 2 in.

Then there is the top chord or rafters that are angled to make the roof pitch. Truss that supports creeper trusses and creates hip roof plane. The parallel chord or flat truss gets its name from having parallel top and bottom chords. Truss that creates roof planes and does not support other trusses truss that creates hip plane by truncating and allowing hip jacks truss top chords to fly over.

Variance from the design dimensions is also allowed. Similar to the raised heel truss this type also creates a vapor barrier creating great insulation characteristics. The more complex the truss framework is the greater quantity of these joints will be required. Any weight imposed on the end truss is directly transferred to the endwall which transfers the weight to the foundation.

Complying with the erection tolerances specified in sbca s bcsi b1 summary sheet is critical to achieving an acceptable roof line. The same thing is true for the bridge of the truss. Dropped chord roof truss. The dropped chord variant is composed of a convention truss with a secondary chord truss suspended below to help reduce uplift.

Bottom chords is at least 3 12 or the bottom chord pitch is no more than half the top chord pitch. All truss designs are optimized to provide the most economical configuration for the specific application. 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. Closed in which the bottom chord is horizontal and at the foot of the truss and open in which the bottom chords are raised to provide more open space also known as raised bottom chord trusses.

Finally the truss calculator will compute the best dimensional method to connect the pieces of the truss with steel joints and a bridge. The bottom chord which is the bottom of the framed truss. Some common trusses are named according to their web configuration such as the king post fan fink or howe truss. See gusset construction below.

There are three parts to the roof truss that you have to know. These trusses are positioned on the top plate of the endwall so the entire bottom chord is supported by the wall. Hip end trusses that are supported by hip truss and creates hip plane. There are two main types of timber roof trusses.