DOES SILICONE BREAK DOWN WHEN FACED WITH PONDING WATER?
Another very common objection, another common misconception. Many people believe, generally, for one of two reasons, that silicone can’t withstand ponding water. The reasons for this belief are generally that someone previously worked with acrylics, or that someone assumes a coating can’t become solid. Let’s examine the reasons for this belief, and the truth of the matter, further.
Why People Believe this Myth
Many other roof coatings, acrylic included, cannot withstand the presence of ponding water. Acrylic coatings tend to break down rather quickly when exposed to ponding water. That’s why it’s so important that a roof be able to completely drain itself before installing an acrylic coating. However, silicone is formulated differently from acrylics, and it can withstand ponding water.
Another reason people think silicone can’t withstand ponding water is that they perceive silicone as a liquid. While silicone never becomes a “solid”, it cures and is no longer liquid either. It turns into a rubber-feeling substance. Rubber is highly waterproof and can withstand ponding water, and silicone is no exception. The belief that silicone remains more of a liquid for its entire life makes it understandable that some would think it can’t withstand ponding water.
How Does Silicone Withstand Ponding Water?
Silicone withstands ponding water due to its chemical formulation. Silicone is a moisture-cured product; it pulls moisture out of the air to cure itself. As silicone cures, its chemical structure fills up with H20. Eventually, the structure becomes completely crowded and the silicone can’t hold any more water. This is what makes silicone waterproof and allows it to withstand ponding water. Water can’t harm silicone because it can’t penetrate it. Once silicone is completely cured and has absorbed all the water it can, it is no longer affected by water, ponding or running.
The myth that silicone coatings can’t resist ponding water is simply not true. Silicone coatings perform very well under ponding water. They don’t break down, they don’t chalk off, they don’t lose adhesion, and they don’t lose their reflectivity. Silicone coatings are formulated to “want” water, so they aren’t harmed when faced with ponding water. This ability allows building owners to leave small areas of ponding water while still utilizing a roof coating.