A.Martin Obando, director of application specifications for the Cedar Shake and Shingle Bureau, responds: A shingle less than 8 inches wide should receive only two nails. However, a shingle 8 inches or wider should receive four nails. The extra two nails should be placed near the center of the shingle, about an inch apart.
Experience has shown that two nails in the center of a wide shingle are less likely to cause the shingle to split than a single nail in the center.
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