How does muriatic acid clean masonry and affect paint adhesion?
A masonry surface becomes rough, or “etched”, when it reacts to strong acids. When the powder residue of the reaction (calcium carbonate) is rinsed off, you are left with a very clean surface. Masonry tends to be alkaline, which prevents proper adhesion of many coatings and paint products. Acid washing neutralizes this alkalinity, leaving a coating-friendly surface. (Note: Before coating masonry check the coating’s label for acceptable surface alkalinity.
