Roof Truss Terminology Pdf

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.

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. 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. The terms pitch and slope are simply two different ways of expressing the same measurement. Terminology timber framing roof structures note.

Some of the more common are listed below and are illustrated on pages 3 4. It is fixed to ends of battens purlins or verge rafters. Cantilever that structural portion of a truss which extends beyond the support. A truss is a frame that supports loads by efficiently transferring its forces to end supports.

Framing terms knowing the basic vocabulary is a necessary part of your work as a builder. 1 4 aspects of truss design for roof structure 1 4 1 truss or i beam for the same steel weight it is possible to get better performance in terms of resistance and stiffness with a truss than an i beam. Trim along the edge of roofing at a gable end. More recently a roof truss means a prefabricated structural timber.

The following glossary assumes that longitudinal is the direction in the ground plan which runs parallel to the ridge while transversal is the direction. Trusses of the roof are not entirely independent as in a common rafter roof but connected and supported by longitudinal members. Slopes at roof pitch. 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. The highest point on a truss. The part of a truss where the top chord and bottom chord intersect figures 3 6. Bearing must occur at a truss tjoint location.

This difference is more sensitive for long spans and or heavy loads. While stick framing might use larger 2x8 2x10 etc. Roof features associated with basic roof framing terms are shown in figure 2 2. 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. Quite common until the 1920 s the function of a roof truss is to support the purlins. Truss terminology technical terms used in the truss industry may not be familiar. A truss that supports other trusses beams or rafters figures 1 2.

Sometimes found in very large buildings where big rooms resulted in few load bearing walls. A purpose designed tile that covers the ridge of a pitched roof. The full use of this advantage is achievable if the height of the truss is not.