In this paper, we present data to support the idea that spherical micron-sized fillers enhance the elastic properties of a coating at a given pigment volume concentration relative to a standard inorganic filler. This is true for rigid glass microspheres and even more so for resilient thermoplastic microspheres. Elastomeric waterproofing coatings are primarily applied to roofing materials to protect and seal them by providing a flexible, water-resistant seal that prevents leaks and mitigates the effects of weathering. In recent years, this class of coatings has also come to be known as elastomeric cool roof coatings [1]-[4], as they ...