MDF (Medium-Density Fiberboard)
Affiliate link — we may earn a commissionMDF is an engineered wood panel made from wood fibers bonded with resin under heat and pressure. It comes in 4x8-foot sheets, typically 1/2-inch or 3/4-inch thick. The surface is dead flat and smooth with no grain, knots, or voids. It machines cleanly, takes paint well, and costs less than plywood. The downside: it's heavy (a 3/4-inch 4x8 sheet weighs about 97 lbs), it swells and disintegrates when it gets wet, and the dust is extremely fine. MDF is the standard material for painted cabinet doors, shelving, trim profiles, and speaker enclosures.
Why It Matters
MDF works when you need a flat, paintable surface and the piece won't get wet. Cabinet doors, closet shelves, wainscoting panels, and baseboards. Don't use it in bathrooms, kitchens near the sink, or outdoors. One soaking and the board swells permanently. Also, always wear a dust mask when cutting it. The fine particles are a respiratory hazard.