How do I calculate a capacity for lumber sheathing or heavy timber decking diaphragms?

AWC’s Special Design Provisions for Wind and Seismic, Table 4.2D contains shear capacities for lumber sheathing attached straight and diagonally. Table 4.3D contains shear wall capacities for straight and diagonal lumber sheathing as well.

AWC also publishes Plank and Beam Framing for Residential Buildings (WCD-4) (T14). It shows how this floor and roof framing system, traditionally used in heavy timber structures, can be adapted to home building.

The International Building Code contains design capacities for diagonally sheathed lumber diaphragms in section 2306.3 Wood Diaphragms. Visit for ordering information.

Analysis Methods for Horizontal Wood Diaphragms by Jephcott and Dewdney from proceedings of a Workshop on Design of Horizontal Wood Diaphragms (ATC-7-1) conducted by Applied Technology Council on November 19-20, 1980 (25 pages). Visit their website at to order.