Timing and Roofing

You may ask?

With my 30-year asphalt roofing shingles are coming close to the end of their rated life. The roof doesn’t have any leaks or other obvious problems, so I’m not sure whether to have it reshingled. What does a roofer look for when deciding whether it’s time for new shingles?

A professional answer:

In addition to leaks, there are a few signs that shingles need to be replaced. Blown-off shingles don’t always indicate impending failure, but if they’re blowing off under less-than-extreme weather conditions, it’s often a sign of aging and brittleness. We also look at the shingles’ granule coating, which not only gives the shingles their color but protects against UV damage. Some granule loss is typical of aging shingles, but excessive granule loss leaves bald patches, which cause the shingles to dry out rapidly and split. You also want to watch out for curling and lifting, both indicators that the shingles are drying out.

If your shingles are shot, you have two options: a reroof (new shingles installed over the old) or a full replacement (stripping down the roof to the sheathing and installing new roofing). Reroofing is acceptable as long as there is only one layer of shingles and none of them are lifting or curling. If there are two or more layers, or if the single existing layer is curling, lifting, or otherwise unsound, then a reroof is needed.

Some have found that a reroof reduces the life span of new shingles by 20% to 40%. This dramatically decreased life span is a result of the original roof shingles not being as good a substrate as the underlying sheathing. Compared to underlayment over wood sheathing, the old shingles are an uneven surface. This means that the new shingles don’t sit as flat, making them more susceptible to movement and blow off. Over time, the subtle bends created in the new shingles are the first places to develop cracks. Also, fastening through the old shingles reduces the pullout resistance of the nails. While manufacturers don’t come right out and say that reroofs don’t last as long, they make the point in a roundabout way because their watertight warranties apply only to new installations and full replacements, not reroofs.

Labor is likely to be the same regardless of shingle grade, so I would go for the highest grade of shingle you can afford. The difference in price is likely to be minimal, and the increased thickness and weight of premium shingles make them more resistant to high winds.

Your roof is vital to the longevity of your home, and yet most people have no idea how often they should replace their roof. The lifespan of your roof is dependent upon a few key factors that are under your control.

First, the biggest impact on the lifespan of your roof will be the material you choose. Generally, the cheaper your roof the shorter the lifespan and the more likely it will need maintenance. A more expensive roof will last you longer, and you won’t have to maintain it as often. On average your roof should last you between 20 and 50 years. You’ve already invested so much into your home, so don’t hesitate to invest in a good roof.

One major impact on the longevity of your roofing system is the quality of the install. Even if you pay for the very best materials a bad installation will fail over time. Make sure you are doing your research and choosing a reputable roofing company. Find out how long they have been in business. Look up reviews and testimonials. Ask your neighbors who installed their roofs and if they have had any issues. Check for warranties, reputable companies will have warranties on both the materials and the installation. Last, choose someone local. Local roofing companies will be invested in the community and dedicated to building lasting relationships with their customers.