A solvent free emulsion adhesive designed to provide a permanently tacky film to prevent loose lay carpet tiles from moving. It allows the tile to be lifted and replaced easily without remedial work. Non-flammable and resistant to plasticiser migration. The tackifier has an added rust inhibitor element, which prevents the product from causing oxidation when used on raised access flooring or other metallic subfloors. The tackifier is protected against biodegradation and is suitable for use over underfloor heating installations.