I’ve started to notice light yellow staining on my newly lime plastered walls where woodfibre has been installed. Followed the installation of the woodfibre boards as per instructions provided and secured them with both board render and mechanical fixings. Could this be tannins from the woodfibre leeching through the plaster? And should so be concerned? I’m not overly concerned about the colour of it, just what the causes might be. I used 40mm steico boards. Anyone have experience of this? The walls have only been completed within the last fortnight. It’s not happened on the walls where I used insulated lime plaster.