Whitewash is a thin-consistency paint made of water, chalk, and lime. It easily absorbs into the medium being ‘washed’ instead of adhering to the surface like a traditional paint. Whitewash is often applied to masonry because it is porous and otherwise difficult to clean. Stone, brick, and rough-cut lumber are appropriate surfaces to whitewash as they receive the product well and collect dust, dirt, and debris if left untreated.
The surface being treated must be dampened before applying whitewash, otherwise the water in the mixture will be absorbed too quickly and leave behind a powdery dust. Whitewash also has a very low opacity; therefore, the application typically requires multiple coats to achieve the desired aesthetic.
Historically, whitewash was a low-cost alternative to paint. People often made it themselves by mixing household staples, such as flour and salt, with raw substances found in nature. Whitewash varies in color depending on its mineral composition, but most have a cream-colored base that can easily be tinted yellow, pink, or brown.
Whitewash is also antimicrobial. The interiors of rural dairy barns were often slathered with the mixture to help prevent disease among livestock.