Abstract: In order in a floor drainage trough installation substantially to prevent gaps between the upper edge portions of the side walls of the floor drainage trough and the body of concrete in which the trough is set, such gaps resulting from shrinkage of the concrete as the body of concrete is cured, strips of woven glass fiber material are provided in the upper edge portions of the side walls of the trough during the molding thereof, with closely spaced loops of the glass fiber material of which the strips are formed being coated with the plastics material of which the trough is formed during the molding of the trough and outwardly projecting under the influence of the inherent resiliency thereof by removing the trough from the mold prior to the plastics material becoming fully set.