Fiberboard Density

Density Variations

• Fiberboard comes in three levels of stiffness or density. Particle board is the lowest grade; medium density fiberboard (MDF) is one step up; and the best quality fiberboard made is high density fiberboard. The American Fiberboard Association defines fiberboard as a fibrous-felted, homogeneous panel made from ligno-cellulosic fibers. Fiberboard has an integral bond produced by interfelting the fibers used to make it.

Particle Board

• Particle board is made of softwood flakes mixed together in a solution of resin. This low grade board is not conducive to outside use due to its high susceptibility to moisture damage. With a density of 9.9 to 28 pound/cubic feet, particle board is commonly used as interior underlay or in lamination in the production of low-end furniture.

Medium Density Fiberboard

• Medium density fiberboard or MDF is composed of a combination of softwood and hardwood flakes combined with a resin binder and wax to form panels with a density of 37 to 49 pound/cubic feet. MDF is denser than plywood and more flexible but can break if waterlogged. Environmentally friendly green manufacturing techniques make fiberboard from recycled paper and wood scraps. MDF has been increasingly used by woodworkers looking for a reasonably priced alternative to plywood in shop furniture applications.

High Density Fiberboard

• High density fiberboard is also sometimes called hardboard. This high-end fiberboard contains highly compressed wood fibers and has a density rating of 37.4 to 90.5 pound/cubic feet. Hardboard is used in higher quality furniture, flooring and construction applications where a greater degree of hardness and strength is required.

  Hardboard takes paint and stain well, thereby outperforming plywood in some projects requiring a grain-free appearance.

Cost and Availability

• Not all lumberyards carry the various grades of fiberboard. MDF can be particularly hard to find. A standard sheet of MDF, at 49 to 97 inches, costs about twice as much as particle board. A similarly sized sheet of cabinet grade plywood can cost twice as much as MDF. Hardboard falls somewhere in the middle in price between MDF and plywood. It is no wonder then that fiberboard has become rare due to its builder-friendly characteristics and cost effectiveness.