Scientists in Hong Kong have demonstrated a new ultra-white ceramic material that can drastically cool buildings by reflecting sunlight and heat at record highs. The beetle-inspired material gets its ability from its nanostructure, stays tough to the elements and should be relatively easy to scale…
Ultra-white ceramic cools buildings with record-high 99.6% reflectivity::undefined
Probably illegal here because of the high reflective value. Depending on the sun's position, it could dazzle and blind people, e.g. people driving cars or riding bikes. I know that for this reason, shiny metal roofs are not allowed.
There is a difference between mirror like reflection and diffuse reflection.
Mirror reflection is what you get with metal roofs which beam the sun directly to a target resulting in one spot being blinded.
Diffuse reflection will spread it around, resulting in more light all around which is what we can handle as humans.
It's not visibly reflective. Yes, it's white, but it's cool to the touch because the majority of the energy is radiated out into space via non-visible wavelengths. Someone has already posted a great YouTube video from Night Hawk In Light in a comment where he explains how this tech works and makes his own paint!