Inspecting Asphalt Shingle Roofs
Asphalt shingle roofs are a common and cost-effective roofing choice, valued for their durability, ease of installation, and wide range of design options. They are lightweight, energy-efficient, and suitable for most residential structures. When properly installed and maintained, they typically last between 20 to 30 years.
During a home inspection, we assess asphalt shingle roofs by examining their overall condition, looking for visible signs of wear such as curling, cracking, or missing shingles. We also check for granule loss, which appears as bald spots or excessive granules in gutters—an indicator that the shingles are nearing the end of their service life. Attention is given to roof penetrations (like vents and chimneys) to ensure flashings are properly sealed and that no fasteners are exposed. We inspect valleys, ridges, and edges for correct installation, and note any signs of water intrusion, staining on soffits, or moisture damage inside the attic. A moisture meter may be used in interior spaces beneath suspected leak areas.
We also consider the roof deck material—asphalt shingles must be installed on OSB or plywood, not on older shiplap or spaced plank sheathing, which can lead to premature failure due to movement from thermal expansion. This is especially important when a home originally had wood shakes, which are often installed directly over shiplap and will require proper sheathing if replaced with shingles.
Common issues we find include moss growth under tree cover, improper nailing, and poor attic ventilation—all of which can shorten the roof’s lifespan. Identifying these problems early allows homeowners to plan timely maintenance or repairs, helping to avoid leaks and costly structural damage.
Below are three examples of issues discovered on a recent inspection, where a roof harness strap was left behind, a downspout is improperly discharging onto a roof surface, and water-tight washers missing from a skylight.
