Roof Sheathing Diaphragm

Roof sheathing consists of 4 x 8 foot apa panels with stiffeners pre framed at 16 or 24 inches on center.

Roof sheathing diaphragm.

Wood structural panel roof sheathing. Abstract this study provides an appraisal of the diaphragm action of such full size wood building components as floors roofs and walls. 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. A diaphragm structure results when a series of such vertical and horizontal diaphragms are properly tied together to form a structural unit.

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 term diaphragm is usually applied to roofs and floors. Minimum roof sheathing thickness excerpt roof sheathing thickness rafter truss spacing 24 in. 140 wind speed mph 150 mph 160 mph minimum sheathing.

The long dimension of the panel typically is oriented parallel to the supports. Maintain ridge nailing by adding additional blocking set back from the ridge or by using vent holes see. Diaphragms are a roof floor or other system transferring lateral forces applied to a building to the vertical elements such as the shear walls. Where they were not capable.

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. Maintain ridge nailing by adding additional blocking set back from the ridge or by using vent holes see. A shear wall however is a vertical cantilevered diaphragm. The roof diaphragm its connection to roof framing and roof to wall connections.

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. Because all adjacent panel edges occur over and are nailed to com mon framing members the roof forms a blocked diaphragm thus providing signifi.