Yellow stuff inside PVC windows.

Hi all, I’ve just noticed that the internal window boards and reveals seem to be stained with yellow splashes. Looking closer, there seems to be some yellow stuff coming out of a small crack and maybe that’s what has been seeping down. What on earth is it? Is it some sort of mould, or maybe water penetration mixing with some sort of hidden rust? There is a concrete lintel above the window. 


Sign In or Register to comment.
Latest MSE News and Guides

British Gas prepay meter users... pay less for gas from 1 April

MSE News

The 'odd Easter flavours' thread 2023

What bizarre food stuffs have you spied?

MSE Forum

Energy Price Guarantee calculator

How much you'll likely pay from April

MSE Tools