The present invention relates to a fibre structure comprising an assemblage of rigidified or rigidifiable fibres characterised in that said assemblage is provided in at least one surface thereof with a matrix layer of a thermoplastic material which is compatible with said fibres and imparts a substantially continuous surface to said assemblage. In a particular aspect of the present invention a layer of thermoplastic material may be located juxtaposed a shaping surface and the assemblage of fibres capable of shrinking on heating, said shrinkable fibres being clamped about said shaping surface to restrain shrinkage thereof in at least two dimensions and thereafter heating the material whereby the shrinkage forces generated by the fibre assemblage is caused to act against the forming surface thereby to force the fibre structure into the thermoplastic material. The structures in accordance with the present invention have been found to be particularly useful in ducting, tubing conduiting or decorative panels for use in vehicles.