Dulux Trade Weathershield Preservative Primer + (BP) penetrates into wood to seal and preserve against water damage, decay and blue stain fungi. Provides 8 year weathering durability, when used as part of the full Weathershield exterior paint system. This is Part 1 of Dulux weather resistant and flexible paint system from Dulux Trade. Part 1 is preservative primer, Part 2 is the paint undercoat and Part 3 is the final gloss coat. The 3 part paint system is developed to provide long lasting protection for exterior woodwork. Suitable for both new and previously painted exterior woodwork, it penetrates deep into the wood to guard against rot, sealing the grain to keep out water. Formulation, solvent based and this product should not be thinned. The coverage is heavily dependent on the absorbency of the wood. Up to 25m² per litre may be given as a guide and re-coatable normally within 2 hours, or when fully dry 16-24 hours.