a method for continuously manufacturing a plastic foam reinforced by at least one fibrous material comprising continuously conveying a carrier along a production line , supplying on top of the carrier a foam - forming mixture and at least one continuously moving fibrous material , the fibrous material being non - expansible and having holes penetrable by the mixture , the mixture being supplied above both the fibrous material and the carrier or below the fibrous material and between the fibrous material and the carrier , passing the carrier , mixture and fibrous material between two spaced opposed constricting members which lie one above the other and form therebetween a metering gap for distributing the mixture over the carrier and fibrous material , and allowing the mixture after passing through the gap to freely expand and penetrate the holes of the fibrous material to form a reinforced plastic foam which has an exceptionally flat surface .