Asphalt shingle installation

Asphalt shingles are by far the most dominant roof covering material used in the United States. They account for approximately 75-80% of all roofs on residential houses. There are many other types of roofs, but for this article, I just want to focus on asphalt shingles and their components.

Architectural asphalt shingles

As a home inspector, I have walked on thousands of roofs in my career and seen many failed roofs, both due to age and installation errors. I would say that most failures are due to age and the roof simply being exposed to the elements for 20-30 years. Some other common failures are cracked or split shingles and nails that work their way out of the roof surface and wear through the shingle above them over the years.

A shingle here is completely missing.

Three tab style shingle. Here you can see a lifted shingle, as the shingle nail works its way out of the structure. This will wear through that shingles and lead to a leak.

Cracked shingle. These shingles have failed and aged out. This crack lines up with the butt joint in the shingle below and will leak.

Brand new roof with shingle nails that are not properly driven. This has caused the nail to punch through the shingle surface. This will leak and wind damage will occur very prematurely.

Simply looking at the shingles from the ground is not enough. Ideally, getting on the roof will provide the best vantage point, with drones and cameras being second best. You'd be surprised what you can see with a 10-megapixel photo. Identifying defects on roofs is important because they are expensive to replace and are the first line of defense from the house's worst enemy... water. We have to keep the water out.

Another very important aspect of the roof being in good condition is the insurability of the home. Insurance companies buy or pay for more roofs in this country than anyone, and it's in their best interest to ensure the house they're insuring has a sound roof covering. They could be responsible for replacement of the shingles or any damage that occurs from failure (consult an insurance agent). Normally, they drive by the home and do a cursory visual inspection of the property to make sure there are no blatant issues with the house, the roof being a primary focus.

In conclusion, I could talk about roof defects ad nauseam, but watching for obvious defects and slowly scanning the roof with your eyes is necessary. It's a little like "Where's Waldo" with the consistent but non-repeating pattern. Be mindful of the roof covering and make repairs soon, and budget for replacement of older roofs.