FAQ: Cool Roof Coatings

Can cool roof coatings be thinned, and if so, with what type of thinner?

While you can use water to clean brushes, rollers, and other items used in application, do not thin these products unless label instructions expressly direct you to do so. Our cool roof coatings are ready to use; thinning them can lead to a number of unintended results, including: reduced service life; inconsistent appearance; creating a film that contains gaps or voids; contribute to blistering and peeling; poor hiding and coverage; increased chance of mold growth; and more. Thinning with mineral spirits or other flow enhancing chemicals can ruin a water based cool roof coating, and may violate government Volatile Organic Compound (VOC) regulations.

What effect does ponding water have on cool roof coatings?

Water based coatings do not perform well on roofs that pond water (i.e., areas of a roof that have slow-draining puddles on them). Dirt can accumulate in depressions and inhibit the reflectance of the coating. If a water based coating is under water for a prolonged period of time, the water may work its way under the coating causing it to peel, or erode the coating and create gaps in the film where water can intrude. Positive drainage is needed to flush away surface dirt and retain the reflective properties of the coating. Keep drains clean and re-grade the roof if needed so that ponding does not occur.

Which type of roofing can I use this on? Asphalt shingles? Tar paper? Plywood?

Each product label indicates the surfaces it should be used on, for which applications, and how to use it. If in doubt, check with the manufacturer of the roofing material to ensure that any coating used does not void any warranty on the roof.

Will a roof coating stop the leaks and waterproof the roof?

Complete waterproofing is a system approach, that includes the construction of the roof, the roofing materials and how they are assembled and installed, and coating systems. Over time, with settling and wear on roofing materials, even the best roofs can develop leaks and ponding areas. For best results, ensure there is positive drainage and drains are clean and clear, and repair all leaks and cracks with a roofing cement and reinforcing fabric prior to using a cool roof coating.

Will Cool Roof coatings significantly increase my winter heating costs?

Cool roofs deflect some desired heat gain during the winter. In general, though, cool roofs result in net energy savings, especially in areas where electricity prices are high. Using Cool Roofs to Reduce Heat Islands. (2016, August 12). Retrieved from


Can I coat a rubber roof with a cool roof coating?

Some rubber roofs can be coated with popular acrylic latex elastomeric coatings, some not. Proper surface preparation is a key to proper adhesion, including removing all chalking, dust and dirt and killing and removing mildew by pressure washing. New formulas designed for rubber roofs may be available; if possible, check with the rubber roofing material manufacturer for suggestions. Finally, be sure to test any coating, especially in "trouble areas" such as shady areas, perennially wet areas, or areas where previous coatings have failed or eroded more quickly.


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The information on this site is provided as a free service. It is based on common conditions and may not apply to your specific situation. Please contact a Black Jack representative with specific questions or comments.