DIY Doctor UK DIY Forums

Every time it rains yellow stains appear on the upvc surrounding our double glazed porch. We have just had the porch revamped but the stains still appear and there is no sign where they come from. My first thought was from a rusty nail but none were found. They can be removed with upvc cleaner but has anyone any idea where they come from and how they can be removed permanently thank you

its a fault in the manufacturing process, reclaimed plastic was used instead of new, it cannot be cleaned off. sorry