Sovereign Hey'di K11 video showing the application of a cementitious tanking system to provide a waterproof membrane. K11 can be used on both the negative and positive water pressure sides in buildings below ground, suitable for waterproofing basements, cellars, swimming pools. Can also be used above ground for dampproofing and to prevent rain water penetration, rising damp and for water retaining structures. Sovereign Hey'di K11 has a potable water certificate making it suitable for use in contact with drinking water.