Rooftops & Solar Heat Loads
Insulation coating blocks solar heat loading, significantly reducing heat saturation of roof membrane and heat battery effect. And when heat loading switches off at sunset, there's less accumulated heat load to continue radiating from the mass.
Buildings absorb heat energy from solar radiation. If painted a white color, buildings reflect a high percentage of the visible wavelength. However, that doesn't prevent radiation from penetrating the envelope and heat energy soaking the mass (roofing material, sheathing, framing and insulation). In the case of heat energy soaking fiberglass, rock wool or foam insulation (conductive insulation), that material heats up until reaching a saturation point. After reaching a heat load saturation point, energy is re-radiated into the building. And continues to radiate heat energy after heat loading turns "off" at sunset until reaching a point of equilibrium with interior (together with HVAC support and exterior temperatures. Roof envelope structure and conventional insulation is essentially a heat battery absorbing and storing heat while radiated and releasing until it releasing until exhausted (equilibrium). Having a solar battery is a good thing in cold climates and even works, depending on the volume of mass and type in hot climates. However, during the hot season the typical wood frame roof envelope simply soaks up heat energy and redistributes it.
Insulation coating blocks solar heat loading, significantly reducing heat saturation of roof membrane and heat battery effect. And when heat loading switches off at sunset, there's less accumulated heat load to continue radiating from the mass.
The main point is that ceramic coating functions as a radiant barrier (emissivity + transmittance) while conventional insulation is a heat battery that slows heat transfer down (conduction). Both have strengths and downsides with colder conditions favoring mass and hotter conditions favoring radiant barriers. Combining strengths by using coating over the top of mass-based insulation results in reduced heat loading of mass and allows it to function more effectively.