Abstract: The invention provides a material for use in waterproofing or containment of liquids, gases or solids, the material comprising a layer which comprises an impermeable or a semi permeable barrier and is adapted to facilitate drainage, wherein the material comprises a geomembrane or waterproofing barrier material comprising a plurality of voids which facilitates drainage, said plurality of voids being provided by means of a layer which comprises a cuspated layer, said cuspated layer comprising a plurality of cusps, wherein said cusps are adapted so as to facilitate the joining of the edges or cuspated parts of said material to the cuspated parts of said material at any angle, said cusps having a shape and being located in a position on said material so as to facilitate said joining. The invention also provides a method for the formation of a barrier material from a plurality of samples of material according to the first aspect of the invention.