Abstract: A method and apparatus is provided for applying a plaster-like coating material to the decorative exposed surface of a preform workpiece. The apparatus comprises; means for mechanically advancing a workpiece along the apparatus along a straight horizontal axis over a non-continuous surface; means for engaging the bottom portion of a workpiece to constrain lateral and vertical movement as the workpiece passes along the apparatus; and means for applying a desired thickness of plaster-like coating material to a decorative surface of an advancing workpiece. Both the method and apparatus provide on a consistent basis, a smooth coating with a controlled thickness tightly bonded to the entire exposed decorative surface of a workpiece. The method and apparatus provide a simple, efficient, cost effective and reliable means for applying a plaster-like coating to the exposed decorative surface of a workpiece for use on a commercial scale in the construction industry.