Two types of polyethylene resins are commonly used to produce geomembranes. High density polyethylene (HDPE) is a very UV stable and chemically resistant material. It is currently the standard type of material used to line the bottom of landfills. Linear-Low density polyethylene (LLDPE) is generally specified because of better elongation properties than HDPE. In landfill capping situations it is used due to the potential of differential settlement. It is not recommended in exposed applications. HDPE and LLDPE can be produces with either a smooth or textured surface. Both types of materials are supplied in rolls that are 22.5’ wide.