Thompson Stain Blocking Damp Seal is a high performance interior coating designed to mask unsightly damp and water stains preventing show through on subsequent decor. Thompson damp seal will not trap moisture within the wall but allows it to escape in a controlled manner without spoiling new paint or wallpaper. Thompson Damp Seal can be applied to most interior walls or ceilings including plaster cement and stone. It can also be applied to damp surfaces surfaces below ground level or surfaces where efflorescence is present. Thompson Damp Seal will not cure damp all sources of damp should be eliminated prior to treatment. Can be applied to damp surfaces. Protects interior walls and ceilings against penetrative damp. Allows trapped moisture to escape. Permanently masks unsightly damp and water stains. It will cover approximately 7 square metres per litre.