In the recent newsletter, Dr. Cannara recommends Henry aluminum roof Coating.
Please tell him that the white roof coatings have much better infrared reflectance than the aluminum coating. See government findings at eetd.lbl.gov/coolroof/coating.htm. Note that the Henry coatings have a great amount of toxic material.
Loma Prieta Chapter member
Alex Cannara responds: The white coatings are better reflectors, no doubt, but far more expensive and often not as durable. If someone wants to do white, great! As for the chemicals, the solvent in the oil-based paint is allergenic to some folks, but it's not a lasting air pollutant, and it meets California standards.
To compare overall pollution impacts, one has to start with the paint's precursor chemicals and processing, and go all the way through its application and life on your roof. If there's a white paint that creates half the organic air pollution, but lasts half as long or retains its reflectivity for fewer years, then there would be no advantage to it.
Obviously, one has to study the overall problem and different solutions thoroughly before making a decision. One thing we do know is that painting or reroofing for higher reflectivity has long-term benefit that outweighs any short-term pollution burden.