Cool Colors in Metal Roof Paints and Coatings

SOLAR REFLECTIVE, COOL COLOR COATED METAL ROOFS USING IR PIGMENT TECHNOLOGY

When it comes to metal roof coatings that were factory baked-on and ultra-durable, the trademarked “Kynar” comes to mind.  This technology was and still is made in the fluoro-polymer, solvent-based material and became a dominant, highly durable coating for factory metal panel suppliers. These coatings were developed starting in the 1970’s with stndard orgainc pigments for their color ranges. An option also became availble in the same base material to have colors made with inorganic, mixed metal, infrared (IR) pigment technology developped in Germany which were substanitally more solar reflective in similar colors. Today a larger range of colors is now available from various makers.

FIELD APPLIED INFRARED COATING TYPES

In terms of field applied, metal roof and metal panel IR coatings, these are now available in water-based, acrylics and thermoplastics with ultra-bonding, cross-linking chemistry and acrylic elastomerics  Bottom line is that the same solar reflective IR pigment technology is used and high levels of reflectivity are available, color-for-color as in the factory applied paints. These field-applied coatings clean up with water, are very low toxic and have a higher overall thickness once they are fully dried. However, in order to bond to failing, older Kynar coated metal roofs, some manufacturers are now making specialized “hot” primers, that meet the VOC requirements and adhere very well to the older coated metal.  The acrylic colored IR coatings can be applied over this bonding primer and stick very well.  It is common with some manufacturers to also to have a clear sealer put on over the finished colored reflective coating in order to protect the color coat further, just like the similar purpose clear sealers commonly used on automotive finishes.  This clear coat or “glaze coat” further adds to the dirt shedding quality of the steep-slope, metal roofs.

When full water-proofing is also required for the metal roof, a class of flexible, waterproofing coatings called “elastomerics” is required to seal the metal roof as a whole system. Seams and perforations must be addressed before the alstomeruc is applied with appropriate sealers and resnforcement. This elastoermic coating category is also made for other roof types which are flat or low-slope as well as exterior walls where high solar reflectivity and waterproofing are required.  Key is that a precious few manufacturers make the IR reflective elastomeric coatings, which can also hold colors that reflect the sun’s heat as do the thermoplastics. When used upon walls, any elastomeric product must be able to pass water vapor out through itself so therefore it must be “breathable”. all of this class are not create equal so make sure it both breathes and reflects.

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