a method of forming a composite door is disclosed . the method comprises : mixing together a thermoplastic polymer with an organic fibrous material in a ratio such that the organic fibrous material constitutes 40 to 60 percent by weight of the mixture ; extruding the mixture under heat and pressure to create a thin sheet form ; cutting the sheet to a predetermined size ; removing material from at least one surface of the sheet to create a homogeneous appearance devoid of obvious fibrous particles ; thermoforming the sheet to impart to the at least one surface an exterior three dimensional door surface to create a thin door facing ; and assembling two of the thermoformed thin door facings , a peripheral frame and a core material into a door .