There is provided a liner for a container that provides a gas and moisture barrier. The liner includes a first sealant web of polyethylene that defines a self-supporting layer of the liner. An adhesive layer is applied to an outer surface of the first sealant web, and a metal foil layer is adhered to the adhesive layer. A second sealant layer is attached to the metal foil layer. The second sealant layer may be heat-sealed to the first sealant web so that when the liner is adhered to the inside surface of a container, the liner may be sealed to itself with a lap seal. The first sealant web defines a self-supporting layer because it provides structural support to the liner. Accordingly, the first sealant web advantageously serves as a carrier web for the liner while the liner is being manufactured.