JLC contributor Mark Parlee recently inspected a home in Iowa with major roofing issues. He found a range of reasons why the roof had given out, leaving the house leaky and wet.

All of the leaks stemmed from poor attention to detail when the shingles were being installed and flashed, he said.

These problems included the following:

  • There had been a complete failure to install a new step flashing or even to integrate the new shingles with the existing step flashing.
  • Shingles had been laid without an adequate offset between courses.
  • Shingles had been nailed haphazardly. In many cases, no nails were evident at all, and in others, nails were overdriven or crooked.
  • Shingles had not been accurately cut to fit around the roof vents.
  • No drip-edge had been installed along any of the roof edges.
  • No plumbing vent boots had been installed. Instead, these penetrations had been “black jacked”—asphalt roof cement had simply been smeared around the bases of the vent pipes.
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