Blocking Between Roof Rafters

The most direct load path is for the roof sheathing to be edge nailed to blocking between each rafter.

Blocking between roof rafters. Each block is 2x4 or 2x6 depending on the size of the rafters and is secured to the top plate. Some may call these wood members blocking and deem them as optional. In my experience traveling across the country observing wood framed construction it was apparent that east of the rocky mountains structural wood members in line with supporting walls between roof framing cease to be installed. The blocking panels will provide additional connections between the roof trusses and the top plate of the wall.

Blocking or boundary member. That blocking is then nailed to the wall top plate with three 8d nails per rafter space as prescribed in irc table 602 3 1. Inches 387 mm or less blocking between rafters or roof trusses shall be provided above the braced wall panel in accordance with figure r602 10 8 2 1. Rotation loads on rafters occur when the roof sheathing is resisting lateral loads perpendicular to the rafter because these loads are actually trying to move the top edge of the rafter sideways.

Where the distance from the top of the braced wall panel to the top of rafters or roof trusses exceeds 151 4 inches 387 mm the top plates. Rafter blocking is an essential part of the roof framing process in that the blocks provide a stop for ceiling insulation and a continuous surface for the roof sheathing to be edge nailed to. And often in a humid environment. These connections could allow a greater uplift force to be resisted.