Signs Your Roof Was Installed Incorrectly — What New Jersey Homeowners Should Look For

Even brand-new roofs can fail if they were installed poorly. In New Jersey’s climate—strong winds, heavy rain, snow, and temperature swings—mistakes become obvious fast. Knowing the warning signs can save you thousands in repairs and prevent long-term structural damage.
Here are the most common signs your roof was not installed correctly.

1. Shingles That Don’t Lay Flat

Shingles should sit cleanly and tightly against the roof.
Signs of a bad installation include:

Curling edges
Lifting shingles
Misaligned rows
Visible gaps
This often happens from improper nailing, uneven decking, or rushed installation.

2. Exposed or Incorrect Nailing

Nails should be hidden under the shingle above.
Improper nailing includes:

Nails placed too high (“high nailing”)
Nails driven too deep
Angled nails
Nails visible on the shingle surface
Poor nailing dramatically lowers wind resistance and can void shingle warranties.

3. Missing or Improper Flashing

Flashing protects high-risk water entry points like:

Chimneys
Skylights
Wall transitions
Pipe penetrations
If flashing is reused, bent, missing, or sealed only with caulk, leaks are guaranteed.

4. Stains, Leaks, or Moisture in the Attic

Signs of improper installation often show indoors first:

Dark stains on rafters
Wet insulation
Moldy smell
Light visible through the roof deck
A correctly installed roof should create a completely sealed barrier.

5. Poor Ventilation Setup

Many installers overlook ventilation, but it's critical in NJ.
Poor ventilation causes:

Ice dams in winter
Shorter roof lifespan
Higher AC bills
Mold growth
Your roof needs a balanced system of intake and exhaust vents.

6. Sagging or Uneven Rooflines

Uneven decking, rushed tear-off, or leaving damaged plywood can cause:

Dips
Waves
Soft spots
A new roof should look smooth and even across all sections.

7. Shingles Installed Over Old Roofing

A roof-over (second layer) is cheap—but extremely risky.
Problems include:

Trapped moisture
Hidden leaks
Added weight
Shortened lifespan
Sweet Home Construction always recommends a full tear-off for safety and durability.

Why This Matters

A bad installation shortens roof life by years, increases the risk of leaks, and can cause structural damage that costs thousands. Good shingles don’t matter if they’re installed incorrectly.

How Sweet Home Construction Ensures Proper Installation

Full tear-off (no shortcuts)
Correct nail patterns and placement
New flashing at all penetration points
Balanced ridge and soffit ventilation
Synthetic underlayment + ice & water on eaves
Clean, even shingle alignment
Photo documentation of every phase
We build roofs that last—and we do not cut corners.

Final Thoughts

If you see any of these warning signs, don’t wait until the next storm exposes the problem. Catching installation issues early can prevent major damage.