Selected Answers

From Zenith Czora of Durotech Industries, Inc. on January 9, 2018:
When there is likely to be exposure to water pondi ...read more When there is likely to be exposure to water ponding, a waterproofing elastomeric membrane is most suitable. There are different types of waterproofing membranes, but the best ones for this type of application are those which are based on polyurethane, polyurea or hybrid polyurethane/polyurea polymers. They are high-solids or 100% solids and offer superior weathering properties and excellent water-resistance.

From timothy barrett of Barrett Company on December 28, 2017:
Although not a coating, the only real solution is ...read more Although not a coating, the only real solution is reflective concrete pavers set on pedestals. I have never seen any coating stand up to ponding water in the long term.

From ROY CANNON of Pecora Corporation on January 9, 2017:
As with most questions of this type, there can be ...read more As with most questions of this type, there can be more than one correct answer. But in keeping with the spirit of the question, my opinion is that a solvent-cut, 100% silicone polymer-based coating is best suited for flat roofs that may experience ponding water. The primary reason is that, properly formulated, this coating material resists hydrolysis, which can be accelerated by exposure to heat and UV in the presence of water, precisely the conditions referenced in your question. Acrylic emulsioncoatings, as well as solvent-cut polyurethanes, although durable, will be generally more susceptible to the effects of heat, UV, and H2O exposure for extended periods of time. Investigation into testing techniques and methods utilized by specific manufacturers for any roof coating should precede selection of a durable reflective roof coating.