This Dulux Trade Weathershield Exterior Flexible Undercoat is part 2 of a 3-part weather-resistant and flexible paint system specifically developed to give longer-lasting protection for exterior woodwork. It provides 8 years of weathering durability when used as part of the full Weathershield exterior paint system. Please note when choosing a colour, please choose the colour of the chosen topcoat and we will mix the undercoat to the correct shade to suit. To benefit from the full 8 years of protection, first clean and dry the wood surface using a Fungicidal Wash before rubbing down to remove any weathered, greyed wood. Next start by applying one coat of Weathershield Preservative Primer and allowing it to dry for 16 hours. Follow on by applying two coats of Weathershield Flexible Undercoat. Please note that as this paint is mixed to order it cannot be returned or exchanged.