Western Red Cedar 18" R&R Grooved Sidewall Shingles 1/2 square cartons R&R shingles are manufactured from kiln dried Number 1 Grade Blue Label WRC shingles, trimmed for parallel edges with butts sawn at right angles. 8" Maximum Exposure for single course & 14" maximum exposure for double course 100% heartwood, 100% edge grain, 100% clear 1 box covers 50 square feet when installed at a 14" exposure, or 25 square feet at a 7" exposure