I have just bought a Victorian (~1880) semi that I am going to work on for the next year before moving in. The cellar had a fake wooden panel wall which I removed that exposed an old rotten window. I have removed the rotten window and found that two large flags at the front of the house are covering the window opening. I want to fit a new UPVC window into where the old window was and open it up again: The walls are solid brick with the outside lintel made of stone (no cracks or issues that I can see) and on the inside there is a wooden lintel. There is a very small area of the wooden lintel that seems damp and soft (see the left of the image) but mostly it seems solid: What I want to know is - is it ok to fit a new UPVC window into the gap of the internal bricks or should I look to replace the wooden lintel first? Access isn't easy in this area so I imagine this might be a difficult job? I have alerted building control that I am installing new UPVC windows. I've a mate who is a window fitter who is going to come and fit them for me but I need to size them up and order them then building control will come out to check and sign it off. Any advice would be very much appreciated!