Virginia Jenkins
Below are the code provisions in the Virginia USBC related to your questions:
From the Virginia IRC (Residential Code)
SECTION R602
WOOD WALL FRAMING
R602.1 Identification. Load-bearing dimension lumber for
studs, plates and headers shall be identified by a grade mark
of a lumber grading or inspection agency that has been
approved by an accreditation body that complies with DOC
PS 20. In lieu of a grade mark, a certification of inspection
issued by a lumber grading or inspection agency meeting the
requirements of this section shall be accepted.
SECTION R502
WOOD FLOOR FRAMING
R502.1 Identification. Load-bearing dimension lumber for
joists, beams and girders shall be identified by a grade mark
of a lumber grading or inspection agency that has been
approved by an accreditation body that complies with DOC
PS 20. In lieu of a grade mark, a certificate of inspection
issued by a lumber grading or inspection agency meeting the
requirements of this section shall be accepted.
SECTION R802
WOOD ROOF FRAMING
R802.1 Identification. Load-bearing dimension lumber for
rafters, trusses and ceiling joists shall be identified by a grade
mark of a lumber grading or inspection agency that has been
approved by an accreditation body that complies with DOC
PS 20. In lieu of a grade mark, a certificate of inspection
issued by a lumber grading or inspection agency meeting the
requirements of this section shall be accepted.
From the Virginia Construction Code
SECTION 2303
MINIMUM STANDARDS AND QUALITY
2303.1.1 Sawn lumber. Sawn lumber used for load-supporting
purposes, including end-jointed or edge-glued
lumber, machine stress-rated or machine-evaluated lumber,
shall be identified by the grade mark of a lumber grading
or inspection agency that has been approved by an
accreditation body that complies with DOC PS 20 or
equivalent. Grading practices and identification shall comply
with rules published by an agency approved in accordance
with the procedures of DOC PS 20 or equivalent
procedures.
2303.1.1.1 Certificate of inspection. In lieu of a grade
mark on the material, a certificate of inspection as to
species and grade issued by a lumber grading or inspection
agency meeting the requirements of this section is
permitted to be accepted for precut, remanufactured or
rough-sawn lumber and for sizes larger than 3 inches
(76 mm) nominal thickness.
Hope this helps.