After more than two decades inspecting homes across New Jersey, I have seen just about every roof condition there is. The roof is one of the most important systems in a home, yet most people know the least about it. It sits above everything else, taking on rain, heat, wind, and snow year after year. By the time a leak appears inside, the problem has usually been active for a while.
When I perform a NJ home inspection, I spend a lot of time evaluating the roof because it protects every other part of the structure. A failing roof can lead to water infiltration, wood rot, insulation damage, and mold growth. Asphalt shingles are the most common roofing material in New Jersey, and they show clear signs of age and wear when you know what to look for.
The first things I look for
When I arrive at a home, I start by looking at the overall layout and shape of the roof. I note how the shingles sit, if there are waves, sags, or uneven lines that might show weakness in the deck. I check the slope and drainage paths, making sure water has a proper route off the roof. From the ground or with a drone, I can usually see missing shingles, nail pops, mismatched repairs, or sections where the shingles have aged differently.
If I suspect multiple layers, I check the roof edges for thickness or visible old shingles underneath. An overlay saves money up front but traps heat and moisture and hides any damage in the sheathing. It is common in older NJ homes, and I always document it clearly.
Common problems I find on asphalt roofs
Asphalt shingles wear in predictable ways, but the reasons vary. Below are the problems I see most often and why they matter.
Granule loss and surface wear
The small colored granules on asphalt shingles protect them from sunlight. When these start washing into the gutters or forming bare spots on the roof, it means the shingles are breaking down. Once the asphalt underneath is exposed, the material dries out and cracks, and leaks are not far behind.
Curling, cupping, and blistering shingles
Old age, trapped heat, or poor attic ventilation can make shingles curl or bubble. Curled edges lift in strong wind and allow rain to blow underneath. Blistered shingles can split open and expose the fiberglass mat. These conditions shorten the lifespan of the entire roof and are often a sign that replacement is close.
Exposed or rusted nails
I frequently see nail heads visible on the surface or along ridges. Nails should always be covered by the shingle above. When they are exposed, they rust and form tiny leaks that slowly rot the roof decking. Rust stains, popped nails, or dried sealant around fasteners are all warning signs.
Improper ridge and hip caps
Roofers sometimes bend regular shingles over the ridge instead of using actual ridge caps. Standard shingles are not designed to bend, so they crack and lift over time. That opens a path for water to enter along the ridge, which is one of the most vulnerable points on any roof.
Flashing failures
Flashing is a common weak point. Around chimneys, skylights, and walls, I see old tar patches, loose step flashing, or metal so rusted it flakes apart. Kick-out flashing is often missing where a roof meets a wall, letting water run right behind the siding. These are some of the most common causes of interior leaks.
Multiple layers and overlays
Many older roofs in New Jersey have two layers. A second layer hides old problems, adds weight, and traps heat. When it is time for a new roof, the only proper fix is a full tear-off so the decking and flashing can be inspected.
Improper attic ventilation
Poor ventilation causes more roof failures than most people realize. When the attic cannot breathe, heat and moisture collect under the deck, cooking the shingles from below and causing mold to grow on the sheathing. I often confirm this using my thermal camera, which shows heat pockets in unvented attics.
Moss, lichen, and debris buildup
Shaded areas on the roof, especially on the north side, often grow moss and lichen. These hold moisture against the surface and lift the shingle edges. Gutters full of debris trap water and ice along the lower edge, leading to early deterioration. Keeping the roof and gutters clean goes a long way toward extending roof life.
Cracked or failing vent boots
The rubber collar around plumbing vent pipes dries out and cracks from sun exposure. When that happens, water runs right down the pipe and into the ceilings below. It is one of the smallest but most common leak sources I find.
Roof life expectancy and what affects it
One of the most common questions I get during a home inspection is, “How long should an asphalt roof last?” There is no single answer because so many factors affect lifespan.
A standard three-tab asphalt roof generally lasts around 18 to 20 years in New Jersey’s climate. Architectural or dimensional shingles tend to last 20 to 25 years when properly installed and ventilated. High-end shingles or designer lines can sometimes reach 35 years or more, but only with good attic airflow, proper flashing, and regular maintenance.
What really determines how long a roof lasts is how it was installed, how much ventilation it has, and how well it has been maintained. Even a premium shingle can fail early if the attic traps heat or moisture. On the other hand, a midrange roof that is well ventilated and kept clean can last well past its rated life.
The environment also plays a big role. Salt air near the shore, heavy tree cover, or repeated freeze-thaw cycles can all shorten shingle life. I have seen 15-year-old roofs that are shot, and I have seen 25-year-old roofs still performing fine. The difference is almost always care and ventilation.
Roof age and homeowners insurance
Homeowners insurance companies pay close attention to roof age and condition. Once a roof passes 20 years, many insurers begin asking for proof of maintenance or may reduce coverage for water damage. Some will only pay the depreciated value on an older roof rather than full replacement cost.
If a roof is near the end of its life, it can even make it harder to get a new policy. Insurance companies want to avoid claims for preventable roof leaks. During a NJ home inspection, I document the roof’s condition, visible defects, and estimated age so buyers can plan ahead and avoid surprises later.
What I tell clients about roof condition
When I inspect an asphalt roof, I explain what I see in plain language. If it is still functional, I say that. If it is worn and nearing replacement, I explain why. My goal is to help clients understand the roof’s remaining life, what repairs are practical, and what to expect with maintenance or insurance down the road.
A roof is not just shingles. It is a system that includes flashing, ventilation, and drainage. When those parts stop working together, leaks follow quickly.
Final thoughts from a home inspector in New Jersey
A good asphalt roof can last for decades, but shortcuts during installation or lack of maintenance will shorten that life quickly. Understanding roof condition is one of the most valuable parts of a detailed NJ home inspection.
An older roof may look fine from the ground, but that does not mean it will pass an insurance inspection or last another ten years. When you know what to look for, you can make an informed decision and plan ahead.
If you want to learn more about what NJ home inspectors check during a roof inspection, visit LookSmart Home Inspections for more information.
About the author:
John Martino is one of the most experienced home inspectors in New Jersey, with more than twenty-four years of experience and over six thousand inspections completed. He is a Board Certified Master Inspector and owner of LookSmart Home Inspections. John performs one inspection per day to ensure every client receives a detailed report with photos and clear explanations that make sense.