What is a potential result of applying oil-based coatings over alkaline surfaces?

Applying oil-based coatings over alkaline surfaces can lead to saponification. This chemical reaction occurs when the alkaline materials, such as concrete or masonry, interact with the oils in the coating. In the presence of moisture, the alkaline environment can cause the oil to break down, forming soaps and other compounds, leading to a compromised coating.

Saponification is particularly problematic because it diminishes the adhesion and integrity of the coating, resulting in defects like peeling or blistering over time. This reaction emphasizes the importance of preparing surfaces properly prior to application to ensure that oil-based coatings adhere effectively and retain their protective properties. Recognizing the potential for saponification helps inspectors ensure adherence to best practices in coating applications, especially on surfaces with high pH levels.