Medium-density fibreboard (MDF) is often selected by builders and do-it-yourself homeowners for building bookcases, cabinet boxes, workbench tops and other household items that need a sturdy base. MDF is far less expensive than quality hardwood lumber, but has other limitations, such as weight and a complete intolerance to water. MDF is porous, so you must prime it before painting, both to protect the MDF from liquids and to provide a smooth, even finish for the paint. Priming MDF is something most homeowners can manage without hiring a professional.
Place a drop-cloth in a well-ventilated area. Place wood blocks or paint props on the drop-cloth to hold the MDF above the floor so that none of the edges touch the ground.