Why do you plaster walls?

Before the advent of plaster board (sheetrock), plaster over wood lath was the most commonly used method for creating smooth interior wall surfaces. It normally involved a rough basecoat over the wood lath, and then a smooth, white finish coat to create the final surface.

Since sheetrock has gained popularity, plaster has become less common. However, special sheetrock, called blueboard, as still sometimes used as a base for a finish coat of smooth white plaster. This is a high end treatment that creates a smooth, seamless, hard, and extremely durable wall surface. Applying the plaster in this way is a tricky process that is best left to professional plasterers.