Is Roof Eave Blocking Required to Transmit Wind/Seismic Forces?

The use of wood blocking between wood rafters or trusses has been historically accepted by engineers as necessary to act as a wood roof diaphragm boundary edge member, to transfer chord forces to the chord and to transfer wind and seismic shear forces to the shear walls. However, the use of eave blocking has been abandoned by many design engineers who argue it is not specifically code-required and that empirical testing has shown it is not needed. They argue that chord and shear forces can be resolved through the use of other framing members and metal connectors. However, engineering mechanics and metal connector manufacturers' limits dictate that eave blocking cannot be omitted. In low load, low heel height cases, it could be argued that eave blocking may not be needed, but where roof diaphragms transfer wind and seismic forces, design engineers omitting eave blocking do so in denial of basic engineering principles.