Estimating Cedar Shingles
Calculate the number of squares you'll need; then figure four bundles per square.
When installing a cedar-shingle roof, use only No. 1 (blue-label) shingles because they’re free of sapwood and knots. Lesser grades are fine for siding but may leak on a roof. Shingles come 16 in., 18 in., and 24 in. long, with recommended exposures of 5 in., 5 1⁄2 in., and 7 1⁄2 in., respectively, on roofs with a 4-in-12 slope or steeper. Ultimately, slope determines exposure and thus the number of bundles per square (100 sq. ft.).
In general, four bundles will cover a square. To calculate the number of squares you’ll need, calculate the square footage of the roof and divide by 100. Because shingles are doubled along eaves and rakes, add an extra bundle for each 60 lin. ft. of eaves or rake. For valleys, add an extra bundle for each 25 lin. ft. For ridges and roof hips, buy preassembled ridge caps, sold in bundles that cover 16 lin. ft. One Canadian supplier, WoodRoof (www.woodroof.com), has an especially informative website about hip and ridge caps, precut “fancy butt” shingles, specialty tools, and more.
You’ll need 2 lb. of 4d or 5d galvanized shingle nails per square of shingles. For shingle caps along ridges and hips, use 6d shingle nails to accommodate the greater thickness of materials. If possible, have your supplier deliver the materials in a lift-bed truck so that you can unload the shingles directly onto the roof.