Thompsons One Coat Damp Seal is a micro-porous, breathable formula that can be applied directly to damp walls and ceilings. It allows trapped moisture to evaporate over time, preventing paint flaking or wallpaper peeling. Suitable for interior walls and ceilings, this solvent-based sealant can be applied with a brush or roller. One coat is enough to cover 5 square meters per liter. Clean up with white spirit.