Ask for a quote for trusses at 16 and 24 on center. When it comes time to plan your building, contact your building supply store to get quotes for your truss: slope, span, and spacing. 2 (Framing and Sheathing a BCI Roof)Ĭalculating your truss spacing is an exercise in economics. The trusses of post frame buildings are firmly attached to those deeply embedded vertical columns with rather than traditional roof structures that are connected with light steel connectors.įraming A Roof With I-Joists Pt. Thus resulting in destruction due to the shear point above grade level. Traditional stick-built structures attach to a foundation at ground level and are vulnerable to ripping loose.

The deeply embedded vertical posts when sunk to a level of at least four feet and on concrete piers provide a substantial grounding that holds the structure in place. The design allows the buildings to minimize damage caused by the deadly forces of these storms. Investigators have found that post frame structures fare surprisingly well in the tornado-prone areas of the Central United States. Since the weather is a critical factor, how well do these hold up in the severest of weather conditions? Many post frame or pole barn construction use 8-foot spacing between trusses. Thefollowing assumptions have been used: Post Frame Roofs In Severe Weather Conditions Wind loads increase with the elevation above ground level andthe degree of exposure.

Rafter spacing for metal roof