The environment can do some serious damage to roofing. Rain creates puddles, which seep into the roof and cause leaking and damage. Snow can bring weight loads the roof isn’t ready for, plus the follow-up of standing water. High winds can tear up roofing. Surely a nice, calm, 85-degree day with pleasant sunlight won’t hurt your roof, will it?

The Effect of Sunlight on Your Roof


Just like your skin, your commercial roof is sensitive to sun. Here in the western half of the United States, we get plenty of that throughout the year – for instance, our customers in Phoenix get an average of 3,871 hours of sun per year, or roughly 44% of the year. That’s a lot of sun. Sunlight takes its toll in two distinctly different manners: infrared radiation, and UV radiation.

Infrared radiation is what you feel. The heat from the sun might make it annoying to go outside, but your roof is stuck there. This heat can cause cracks, bumps, and other damage to your roof. It can break down the chemicals used in some seam sealants, allowing for the seams to split open. Expansion and contraction from heat can twist, pull, and tear at fasteners, pulling the systems away at terminations and seams. With dark-colored roofing, the heat is absorbed and held in, meaning that even after the sun has gone down the heat may still be working away at the integrity of the roof.

Ultraviolet radiation is the other part of sunlight, and it’s more insidious. Even when it’s cool enough for jeans and sweatshirts outside, your roof is still being exposed to UV rays. Even on cloudy days, UV rays make their way through – the EPA noted that even during the coolest, cloudiest months the UV index in our region is the highest in the United States. These rays can alter the make-up of your roof, degrading the chemicals that are commonly used in bitumen, single-ply-membrane, and pretty much any other roofing type.

The worst part of all this is, you won’t notice the problems until the sun goes away and the rain clouds move in. When it is sunny, you might notice that your climate control system needs to work harder to keep it cool. But when the rains come, the cracking, blistering, and split seams will allow water to work its way down, leading to leaks and potential interior damage. If you haven’t had rain in a while, this can catch you or your tenants by complete surprise.

The Cool Roof Solution To Damage

Technology has been developed to deal with these roof stressors though. Cool Roofs are one of the top suggestions for energy conservancy, but that’s not their only advantage. Yes, they do help to lower energy usage of buildings as they reflect the infrared radiation instead of absorbing it. This reflection also reduces the amount of heat the roof deals with – the EPA has noted differences of up to 50 degrees between a Cool Roof and a Rock or Capsheet roof in the middle of a sunny afternoon.

The other part of Cool Roof systems is a barrier between the UV rays and the materials that make up the system. This UV-reflective barrier protects the structure of the materials below, absorbing the punishment. It may need to be reapplied from time to time, but re-coating is much more cost- and time-efficient than replacing.

Here at Highland Commercial Roofing, we saw early on the effect of the sun on roofing throughout the southwest and West Coast regions that we serve, so we became early proponents of cool roofing. Our RainShield® Roofing System uses Cool Roof technology to reduced damage from infrared and UV radiation. The first phase of acrylic surfacing used in the system helps to block ultraviolet radiation from the roofing itself, while the second phase is reflective white elastomeric, helping to reflect infrared radiation instead of absorbing it. This is on top of the natural water protective features that the RainShield® system has.

The key to longevity for roofing is addressing the environmental needs. If you haven’t addressed the sun issue and you own a building in the western US, then your roof is likely falling apart and you haven’t noticed it yet. So consider retrofitting your roof with specialized heat-reflective material, or investing in a new Cool Roof system. Our team at Highland Commercial Roofing can help you to decide which is the better option for your building, and get you started on improving the usefulness and lifetime of your roof – reach out and contact your nearest Highland Commercial Roofing office today!