shingle overlay

Overview

Asphalt shingle roofing is one of the most common roof systems used across Arizona and the U.S. Homeowners choose it because it offers:

  • Attractive appearance
  • Solid weather protection
  • Good value for the investment

However, shingle roofs are only as good as their installation. Many premature failures come from workmanship issues rather than the materials themselves.

Common Installation Problems

These issues can significantly shorten the life of a shingle roof:

  • Nails placed too high
    Shingles may not seal properly and can slide or blow off.
  • Nails that are too short
    Fasteners may not fully penetrate the decking, leading to loose shingles.
  • “Stretched” shingles (improper overlap)
    When shingles aren’t layered correctly, water protection is compromised.
  • Improper attic ventilation
    • Too little ventilation → heat and moisture buildup
    • Too much or poorly balanced ventilation → performance issues
      Both can damage the roof system from below.
  • Overlaying new shingles over old shingles
    While this may reduce upfront cost, it often leads to:
    • Shorter roof lifespan
    • Hidden deck issues
    • Poor nail holding strength
      The savings rarely outweigh the long-term performance loss.
Shingle Roof Overlay

Signs of Poor Installation

All of the above problems can lead to premature roof failure.

The most common visible warning sign is:

  • Windblown or missing shingles
Windblown Shingles

While strong winds can occasionally remove a shingle or two, large sections of missing shingles are usually a clear sign of installation problems.

How to Protect Yourself Before Hiring a Contractor

If you’re researching a new roof or concerned about an existing one, you’re already doing the right thing by asking questions.

Here are important questions to ask your contractor:

  • Have you personally installed asphalt shingle roofs?
  • How long has the crew performing the work been with your company?
  • Will there be direct supervision on the job?
  • Are you properly licensed, and is your license in good standing?

Bottom Line

A properly installed asphalt shingle roof can provide many years of reliable service. Most early failures aren’t product issues — they’re installation issues. Taking time to vet your contractor is one of the most important steps in protecting your investment.

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