A geomembrane is a synthetic membrane liner or barrier with very low permeability. It can be used with any geotechnical engineering material to control fluid or gas migration in a wide range of construction and civil engineering applications.
Geomembranes are usually made from relatively thin continuous polymeric sheets. But they can also be made from the impregnation of geotextiles with asphalt, elastomer or polymer sprays, or as multilayered bitumen geocomposites. They are outstanding in resistance to water and aging.