A Few Ways NOT Fasten Shingles

Posted by in Shingles | June 18, 2019

This is how NOT to fasten common asphalt shingles:

With a nail driven at an angle, thus, reducing the pull through strength and causing a hump that lifts the overlying tab.

Figure 1 Roofing nail driven at an angle such that the head cuts into the mat.

With nails over driven so that they are cutting or puncturing the shingle mat, thus, reducing the pull through strength.

Figure 2 Roofing nail overdriven into shingle mat.

With nails set so high that the top of the underlying shingle is not fully engaged, thus, reducing the number of nails fastening the shingle strip from eight to four.   

Figure 3 Roofing nail set so high that it does not engage the underlying shingle.

With no nail at all.

Figure 4 Roofing nail misses top edge of underlying shingle strip.

Roofing nail set in the sealant, thus, reducing the surface area of the sealant and providing a potential hump to prevent contact of the overlying shingle and the sealant.

Figure 5 Roofing nail driven through sealant for tab.

But rather follow the manufacturer’s recommendations.  Shingle manufacturers generally recommend:

  1. Using galvanized (zinc coated) nails with an 11 or 12 gauge shank and a head of at least 3/8″ diameter and a length adequate to penetrate ¾ inches into or through the roof deck.
  2. Using four nails per shingle strip.
  3. Placing nails approximately 6-1/8″ above the bottom edge and 1″ in from each side and ½” above each slot or 13” in from each side.
  4. Driving nails straight (not at an angle) so that nail head does not cut into the mat.
  5. Driving nails until the heads are tight to the top surface of the shingle and not countersunk so that they puncture the mat.