Ronseal super flexible wood primer undercoat utilises a highly flexible resin to improve the performance of your exterior topcoat finish it moves with the wood to maintain adhesion to help prevent cracking and peeling of the topcoat it adheres superbly and both primes and undercoats in one providing the ultimate base coat for any topcoat it also has an advanced stain locking mechanism that creates a barrier stopping extractives and tannins found in resinous woods from discolouring your paintwo