Fast WR30 has an advanced silicone based formulation, which effectively repels water away from all types of unpainted masonry surfaces, thus solving your penetrating damp problem. Fast WR30 has superior penetrating ability, high alkaline resistance, UV resistance, prevents dirt penetration, Efflorescence, moss growth and defacing of interior and exterior walls. The only solution to rising damp. Available in 5L & 25L pack sizes