Commercial Roofs under the Summer Sun

Commercial Roofs under the Summer Sun

Commercial Roofs under the Summer Sun 2500 1406 PB Roofing PB Roofing


Every year as summer approaches, the cold and harsh weather that preceded it is easily and quickly forgotten. It is only natural for thoughts to wander towards summer vacation, recreation, and the prospect of beautiful weather. Far from the minds of many, property managers and owners included, is what impact even a single season of hot weather can have on a commercial roof. Not surprisingly, as with any other seasonal weather scenario, heat can have a significant adverse effect on a commercial roof. It is valuable to realize these effects and how to counteract the potential damage they cause.

Excessive Heat

High roof surface temperatures accelerate the molecular decay of chemicals used in roofing materials, damaging them, and making a roof vulnerable to damage. “Conventional roofs can reach temperatures of 150°F or more on a sunny summer afternoon.” (Energy Saver).

As a commercial building’s roof endures the full force of intense and sustained summer temperatures, it will also affect the temperature of the building interior.

Overhead Utilities

Commercial HVAC expenses will naturally rise in the summer to keep the building cooler and the tenants comfortable. There temperature difference between the cool air inside a building, and the hotter, moisture-laden air outside of it causes moisture to condensation. Too much moisture can be a breeding ground for many airborne pathogens.

Ultraviolet (UV) Exposure

“All radiation is a form of energy, most of which is invisible to the human eye.” (FDA). When sunlight shines on a commercial roof, it also exposes it to the UV radiation that the sun produces. UV exposure is not only harmful to the human body, but also to an array of synthetic materials.

“During the summer months the sun is in a more direct angle, resulting in a greater amount of UV radiation.” (FDA). The rays evaporate oils and resins that roofing materials are made of. The effects of this radiation include faster ageing, cracking, and eventually deterioration. With prolonged exposure, a roof tends to bleach. This is a called photodegradation, and it happens through chemical reactions. This isn’t critical, but can be unsightly, which is something to consider for retail, residential, or office property management.

Thermal Shock

While there’s no better feeling than experiencing thermal shock for yourself with a refreshing swim on a hot summer day, the opposite is true for a commercial roof. Realizing that no roof is completely damage-resistant, especially with unpredictable weather will help you understand why certain roofing problems happen.

Thermal shock is the frequent expansion and contraction of roofing materials due to temperature fluctuation. Commercial roofs endure daily high temperature peaks that cause their materials to expand. When the sun sets and temperatures drop, the reverse process of contraction occurs. The repetition of this process reduces a commercial roof’s structural integrity and weakens the roof’s ability to perform its intended function.

The trifecta of summer heat, UV rays, and thermal shock lead to burst roof seams and loose screws. Penetrations like skylights and vents are most susceptible to this damage.

Summer Storms

As the heat lowers, it’s often followed by heavy precipitation. Only after a heavy downpour does it become obvious just how much summer damage has occurred. The ideal commercial roof is as waterproof as possible. At the forefront of this protection is the sealant used to bond together the roofing seams.

Rainfall collects in standing ponds on the roof. The weight of this water will eventually cause the roof to sag. If water gets underneath an unattached seam, it will seep into the interior of the building and soften it. Soft spots occur when the roofing structure below the surface is infiltrated by water and weakened. Softened materials leave commercial roofs even more defenseless against further weather damage and threaten the entire property’s structure.

When a roof eventually leaks, it results in structural damage to walls and floors, as well as damage to insulation, and mechanical and electrical systems. Another major concern is roof-water leakage seeping into walls and other areas, creating mold.

Drainage & Debris

Because of their low-slope, flat roofs sometimes do not offer the appropriate drainage for sudden rainfall run-off. Most flat roofs are built with a minor slope to allow for drainage, but the lack of a significant natural slope can produce challenges. “There are roof coating products available if there isn’t enough slant or slope to accomplish this.” (RoofSlope).

Leaves, branches, and other debris carried by the wind and blown about the roof surface, easily clogging the drainage systems. This creates areas of standing water, where weight can suddenly weaken the roof’s surface.

Preventative Maintenance

The positive news is that the damage caused by heat and other factors during summer is a cumulative effect. If a commercial roof is under ten years old, there isn’t much to be concerned about, especially if well-maintained.

Each type of roof system has its own potential for failure. Understanding these potential influences and the overall type of failure provides understanding into developing corrective actions to maintain or extend the life of a commercial roof.

With older roofs, knowing the warning signs, paying attention to any developing issues, and addressing them quickly will protect your investment in the long-term.

PB Roofing’s THREATCheck

Now that you understand the many potential hazards to a commercial roof, you can be assured that protecting your structure is worth the investment. Our THREATCheck is for new customers: one enhanced visual inspection to identify deficiencies and provide recommendations for repairs or replacement. Our Plus Package features the same, with a bi-annual inspection plan. Photo report included.


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