Girder Roof Structure

All girders are beams but not all beams are girders.

Girder roof structure.

Girders are the main horizontal supports of a structure and support smaller beams. Construction of a rafter roof a simple rafter roof consists of rafters that the rafter foot rest on horizontal wall plates on top of each wall. These are often pre fabricated and sent to a construction site. It can bear the load extra loads imposed on it.

Girder is a type of roof truss or beam that is built stronger than a standard truss to support in construction. Buildings constructed in l or t shapes use girder truss systems where the roof changes direction. A truss is a roof or floor support structure built from a connected series of box or triangle shaped elements to distribute load to a building s walls or foundation. Understanding how a girder is different from a beam is a necessary skill for any builder engineer or constructionworker.

The top ends of the rafters often meet at a ridge beam but may butt directly to another rafter to form a pair of rafters called a couple. Girders often have an i beam cross section composed of two load bearing flanges separated by a stabilizing web but may also have a box shape z shape or other forms. Their is no notching permitted in the center third of any beam. Both headers and girders are beams that are oriented horizontally and transfer load down to walls piers or posts.

See the figure below the girder trusses usually are specially made with heavier chords and plates and can consist of a number of trusses laminated with nails or bolts. Notches on the outer thirds must not exceed 1 6 of the width of the board. It is the main horizontal support of a structure which supports smaller beams.