National Coatings Blog

Choosing a High Quality Cool Roof Coating

Posted by Nicole Gale on Tue, May 21, 2019 @ 09:07 AM

Cool Roof high quality

Highly Reflective Coatings

Installing a cool roof coating system will greatly benefit your building and the people inside it. To begin this selection process, it is crucial to understand two things:

  1. What are cool roof coatings
  2. Understanding the importance and benefits of selecting a high quality coating 

What are Cool Roof Coatings

The Cool Roof Rating Council does an excellent job providing accurate and credible, independent test results of different roof coating manufacturers' products. The three main components they measure are solar reflectance, thermal emittance, and a combination of the two called Solar Reflective Index (SRI). Solar reflectance is the amount of solar energy/UV rays that is reflected away from the roof, back into the atmosphere. The higher the solar reflectance is of a coating, the less heat the building has a chance to absorb. Thermal emittance is the relative ability of a roof to emit (or release) heat that has been absorbed. SRI is a calculation method using reflectance and emittance values to determine the roof's overall capacity to refuse solar heat. Therefore, the higher the SRI value is, the greater ability the coating has to reject solar heat absorption, maintaining a cooler temperature inside the building. 

While it is important to take note of the initial solar reflectance and SRI values, you don't want to be influenced too greatly by these initial values. The more valuable testing results will be the long-term success rates, or the 3 year, aged testing results. The 3 year test results will give you a greater sense of the quality of the roof coating and how it will perform in the future. While inferior coatings will often say "we are the same as..." these 3 year values can show different chemistries and the quality of ingredients in the coating. When installing a cool roof on your building, who wouldn't want to use the coating with the greatest long-term performance history!

Benefits of Choosing a High Performance Roof Coating

Now that you know a top quality roof coating will have high aged reflectance, thermal emittance and SRI values, let's dig in a little deeper to find out how that affects the building owner and those inside the building.  As stated above, the higher the SRI value, the lower the temperature of the roof will be resulting in a "cool roof". The cooler roof temperature limits the heat that is conducted from the outside of the building to the inside.  Therefore, with less heat transferring through the roof into the building, the building is able to remain cooler for longer, making it significantly beneficial for the person responsible for paying the cost of the electric bill. Cool roof coatings can substantially lower air conditioning costs and prolong the mechanical systems operational life expectancy. Employees, customers, and everyone else who enters your building will benefit from the cooler temperature!   

Proven Performance

Harbor Freight Tools installed a National Coatings Cool Roof Coating System to their 260,000 square foot roof and this was what they had to say:   

"After the National Coatings' Cool Roof was installed we definitely noticed a difference in building temperature.  It's not a marginal difference, either. It is now between 15° to 20° degrees cooler inside the warehouse and store." - Jerry Moore, Facilities Director at Harbor Freight Tools

For more information on our Cool Roof Coatings and Systems, download our FREE Full Line Brochure!


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