(1)
Shingles and shakes shall conform to,
(a)
CSA O118.1, “Western Red Cedar Shakes and Shingles,” or
(b)
CSA O118.2, “Eastern White Cedar Shingles.”
(2)
Western cedar shakes shall be not less than No. 1 or Handsplit grade, and western cedar shingles not less than No. 2 grade, except that No. 3 grade may be used for undercoursing.
(3)
Eastern white cedar shingles shall be at least B (clear) grade, except that C grade may be used for undercoursing.