Polythene sheet is more properly called polythene film when it is made with a thickness of about one-third millimeter to ten millimeters. These films are normally translucent. They can be made opaque with the use of additives.Polythene sheet used for many kinds of water proofing and can be a permanent weather barrier on exterior walls. It is used in construction and remodeling projects, especially as a vapor barrier in walls. It's commonly used to temporarily seal off rooms and to cover building materials. It is frequently used as a painter's drop cloth. It can be used in curing concrete to retain moisture during the curing period. Some tarpaulins and tents are made from polythene sheet.