Roof Truss Terminology Pdf

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.

Roof truss terminology pdf.

Cantilever that structural portion of a truss which extends beyond the support. Roof features associated with basic roof framing terms are shown in figure 2 2. Quite common until the 1920 s the function of a roof truss is to support the purlins. The following glossary assumes that longitudinal is the direction in the ground plan which runs parallel to the ridge while transversal is the direction.

More recently a roof truss means a prefabricated structural timber. The full use of this advantage is achievable if the height of the truss is not. All truss designs are optimized to provide the most economical application. Bearing must occur at a truss tjoint location.

The terms pitch and slope are simply two different ways of expressing the same measurement. A truss is a frame that supports loads by efficiently transferring its forces to end supports. Truss terminology technical terms used in the truss industry may not be familiar. The highest point on a truss.

The part of a truss where the top chord and bottom chord intersect figures 3 6. Trusses of the roof are not entirely independent as in a common rafter roof but connected and supported by longitudinal members. It is fixed to ends of battens purlins or verge rafters. 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.

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. Trim along the edge of roofing at a gable end. Terminology timber framing roof structures note. A truss that supports other trusses beams or rafters figures 1 2.

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. In the following section we ll cover some of the more common roof and rafter terms you ll need. Sometimes found in very large buildings where big rooms resulted in few load bearing walls. Roof framing terms are related to the parts of a triangle.

The parallel chord or fl at truss gets its name from having parallel top and bottom chords. Slopes at roof pitch. This difference is more sensitive for long spans and or heavy loads. The same roof has a 4 12 or 1 3 pitch.

Truss terminology bearing width the width dimension of the member providing support for the truss usually 31 2 or 51 2. While stick framing might use larger 2x8 2x10 etc. Framing terms knowing the basic vocabulary is a necessary part of your work as a builder.