Roof Truss Terminology Pdf

Members which are expensive and might require either additional beams or interior load bearing walls trusses can span a longer distance without additional supports while using less expensive members.

Roof truss terminology pdf.

Trim along the edge of roofing at a gable end. Truss terminology technical terms used in the truss industry may not be familiar. The part of a truss where the top chord and bottom chord intersect figures 3 6. Cantilever that structural portion of a truss which extends beyond the support.

The parallel chord or fl at truss gets its name from having parallel top and bottom chords. The following glossary assumes that longitudinal is the direction in the ground plan which runs parallel to the ridge while transversal is the direction. Sometimes found in very large buildings where big rooms resulted in few load bearing walls. Some of the more common are listed below and are illustrated on pages 3 4.

A truss that supports other trusses beams or rafters figures 1 2. It is fixed to ends of battens purlins or verge rafters. Roof features associated with basic roof framing terms are shown in figure 2 2. While stick framing might use larger 2x8 2x10 etc.

All truss designs are optimized to provide the most economical application. The terms pitch and slope are simply two different ways of expressing the same measurement. Roof framing terms are related to the parts of a triangle. In the following section we ll cover some of the more common roof and rafter terms you ll need.

More recently a roof truss means a prefabricated structural timber. Framing terms knowing the basic vocabulary is a necessary part of your work as a builder. Trusses of the roof are not entirely independent as in a common rafter roof but connected and supported by longitudinal members. Terminology timber framing roof structures note.

A truss is a frame that supports loads by efficiently transferring its forces to end supports. Standard roof truss configurations parallel chord 4x2 floor truss with chase 2x4 floor or roof truss can design with a chase as well are determined by span load and spacing. Quite common until the 1920 s the function of a roof truss is to support the purlins. Truss terminology bearing width the width dimension of the member providing support for the truss usually 31 2 or 51 2.

The same roof has a 4 12 or 1 3 pitch. Bearing must occur at a truss tjoint location. A roof s slope is the number of inches it rises for every 12 inches of horizontal run a roof with a 4 in 12 slope rises 4 inches for every 12 inches of horizontal run. This difference is more sensitive for long spans and or heavy loads.

The full use of this advantage is achievable if the height of the truss is not. A sheet metal or pvc profile attached at the end of the overhang of the roof trusses to catch rain water runoff from the roof figure 3 heel. The highest point on a truss.