The wedi building board is the UK's most trusted waterproof tile backer and insulation board for wet rooms, shower enclosures and steam rooms. Manufactured from extruded polystyrene (XPS) foam faced with glass-fibre reinforced polymer, it is 100% waterproof to the core — no separate tanking membrane required. wedi tile backer boards are up to 80% lighter than traditional cement board, can be cut on site with a knife or saw, and are CE marked for use in high-humidity environments. As wedi-certified experts, Wetrooms Online carry the full range with Trade Club pricing and UK delivery.