How Does Sunshine (UV Rays) Damage Asphalt Shingles?

Blog Cover Showing UV Rays Which Can Damage Asphalt Shingles

UV rays can cause significant damage to asphalt shingles prompting costly repair fees and possible total roof replacements. Therefore, understanding how to identify and prevent UV ray damage is paramount.

You may think the winter months are harsh on your roof, and you’re right. Rain, hail, snow, ice dams, and high winds cause issues with your asphalt roof. But the summer sun can be just as potent, a lesson you can avoid.

Think about it; your roof is your property’s first line of defense against the rain and the sun. As a result, UV rays can devastate your asphalt shingles as they gradually penetrate the roofing system and materials.

It’s essential to keep an eye on your roof and identify warning signs of a compromised roofing system. In the following post, Roofer’s Guild answers the question: how does sunshine damage asphalt shingles?’ 

We also provide insight on how to spot shingle damage and tips on protecting your roof from the harm of premature aging. 

Asphalt Shingles on Roof Up Close

Key Takeaway:

UV rays damage asphalt shingles by breaking down their molecular structure, which can cause granule loss, cracks, and material degradation.

Weather Fluctuations

In the summer months, day-to-night weather condition fluctuations can wreak havoc on your shingles. During the day, it may get scorching, giving way to humid nights. 

Humidity fluctuation is terrible for asphalt shingles. During the day, it dries them out and leaves them very brittle. However, when the night is humid, the stark contrast can cause the decomposition of materials. 

This fluctuation (which is more marked in extremely high temperatures) also causes a thermal expansion and contraction of the roofing materials. Generally, this fluctuation is awful for roofing materials and may cause them to fail sooner than expected.

Excessive Heat

In most climates, the sunniest months present constant and excessive heat. It’s hard to think of any living or synthetic material not damaged by extreme heat. Assuredly, your asphalt shingles are certainly one of them. 

You may not notice excessive heat damage until winter when leaks become apparent. That’s because extreme UV damage can cause the asphalt shingles to become brittle and move upwards at the edges.

These effects may not cause roofing problems when the weather is warm and dry, but when it starts raining and snowing, it can cause leaks. There are a couple of ways you can protect your roof against excessive heat:

  • Proper Ventilation: Properly ventilated roofs can go a long way toward keeping your roof cool. However, it would be best to pump cool air into these upper building portions to help the shingles retain as much moisture as possible in the hot sun.  
  • Roofing Inspections: Of course, doing an inspection or hiring a professional to inspect your roof before the summer months can save you from a world of trouble. 

UV Damage

Layers of materials comprise asphalt shingles. At the top is a layer of granules bound and protected by an oily substance. UV rays react with this substance and the oxygen around it to evaporate, leaving the material exposed and vulnerable. 

In essence, UV rays cause oxidative damage that changes the molecular structure of the shingle. Usually, this means a breakdown of the materials that protect the shingle and the roof. 

This can eventually cause the protective granules to fall off, exposing the underlayers. It can also cause the shingle to overdry and start to crack. Dryness is a severe problem, too, because shingles are continually bombarded with UV rays whether the sun is out or not. 

Apart from using special shingles with high UV resistance, there isn’t much you can do to combat this problem. But, as always, frequent inspections can prevent more significant issues. 

Another option is to use a different roofing material on your residential or commercial property, mainly if you live in a sweltering climate.

Weakened Shingles

Granule loss is one of the most common problems with asphalt shingles. The granules on the shingle’s top layer protect them and make them so resilient. 

However, excessive UV radiation and dry conditions can cause granule loss by drying up the shingle and robbing its protective oils and moisture. 

When this happens, the shingles weaken and become vulnerable — leading to splits and cracks that may expose the underlayers of your roof.

Again, you aren’t likely to notice this kind of damage in the summer unless you regularly inspect your roof. However, it can cause many problems in the winter, including roof leaks, shingle warping, and even roof warping. 

How to Address UV Ray Damage for Asphalt Shingles

Whether you are a contractor or home/business owner, it’s crucial to take action as soon as you see:

  • Warped shingles
  • Curled shingles
  • Cracked shingles
  • Missing shingles
  • Shingles with noticeable granule loss

These problems are symptoms of sun damage and must be addressed as soon as possible. Replace any damaged shingles you see and, if possible, upgrade to a new roofing system that is more resilient in intense heat.