Roof Sheathing Diaphragm

Minimum roof sheathing thickness excerpt roof sheathing thickness rafter truss spacing 24 in.

Roof sheathing diaphragm.

When the roof sheathing is used as a structural diaphragm as it typically is in high wind and seismic hazard areas the structural integrity of the diaphragm can be compromised by a continuous vent see figure below left. Maintain ridge nailing by adding additional blocking set back from the ridge or by using vent holes see. A diaphragm is a flat structural unit acting like a deep thin beam. For wood structures diaphragms are commonly constructed of wood structural panel wsp sheathing or decking applied to the upper face of regularly spaced floor or roof wood framing members such as joists trusses purlins or sub purlins.

The roof diaphragm its connection to roof framing and roof to wall connections. Maintain ridge nailing by adding additional blocking set back from the ridge or by using vent holes see. Inherent is the assumption that the sheathing nail will have a penetration of not less than 10 diameters 1 3 8 inches for 8d common and 1 1 2 for 10d common into the planking or decking. When the roof sheathing is used as a structural diaphragm as it typically is in high wind and seismic hazard areas the structural integrity of the diaphragm can be compromised by a continuous vent see figure a below left.

A diaphragm structure results when a series of such vertical and horizontal diaphragms are properly tied together to form a structural unit. Roof sheathing consists of 4 x 8 foot apa panels with stiffeners pre framed at 16 or 24 inches on center. Eight roof or floor panels 20 by 60 feet in size and seven dual wall panels approximately 12 by 18 feet in size were tested under laterally applied load. Diaphragms are a roof floor or other system transferring lateral forces applied to a building to the vertical elements such as the shear walls.

Because all adjacent panel edges occur over and are nailed to com mon framing members the roof forms a blocked diaphragm thus providing signifi. Wood structural panel roof sheathing. 140 wind speed mph 150 mph 160 mph minimum sheathing. Abstract this study provides an appraisal of the diaphragm action of such full size wood building components as floors roofs and walls.

The long dimension of the panel typically is oriented parallel to the supports. Wood structural panel diaphragm sheathing to be fastened over solid lumber planking or laminated decking using full tabulated values for new construction.