Masonite is a synthetic hardboard used for insulation, panelling and general wall construction. It is made of compressed wood chips held together by lignin, a natural binding agent found in the wood. Masonite is produced by heating the wood chips and pressing them together to form large panels. When they are finished, the panels are smooth on one side and can be rough or smooth on the other. Masonite is a versatile, economical, and environmentally responsible product that allows wood scraps that once went to waste to be transformed into valuable building material. The product is sold under the brand names of Masonite and Abitibi.

The invention of Masonite could be considered a fortunate accident. During the 1920s, William Mason, an inventor from Mississippi, wanted to find a use for the tons of wood chips that were going to waste on sawmill floors. With financial backing from a lumber company in Wausau, Wisconsin, Mason worked on some of his ideas. Using a leaky nineteenth-century steam letter press, Mason's intended goal was to produce insulation board. One day in 1924, he accidently left the steam on while he went to lunch. He returned to find that the overdose of steam had produced a tough sheet of hardboard. Further tests proved that the product was resistant to weathering. The following year, Mason established the Mason Fibre Company, to produce his Masonite hardboard. The company later became the Masonite Corporation, which is now a subsidiary of the International Paper Company.