(a) All lumber used to support loads or withstand forces shall be sound and free from rot, decay, shakes, and other defects which affect its durability or impair its strength for the purpose for which it is intended.
(b) All lumber four (4) inches or less in nominal thickness used to support loads or withstand forces in permanent structures shall have been air dried or kiln dried to a moisture content approximately equal to that to which it will eventually come in service.
(c) All lumber used in trussed, or in glued laminated members of laminations two (2) inches or more in nominal thickness, or for other major structural members where deemed necessary for structural safety by the Commissioner shall be stress grade lumber.
(d) Where “heartwood of a durable species” is specified by OBBC and this Building Code, it shall be interpreted to mean the heartwood of tidewater red cypress, cedar, or redwood or other approved decay resistant wood.