Hi
I noticed the rotten looking wooden window ledge upstairs. This had been a problem area before due to a damaged roof but this rotten area is new. When lifted up I found it filled in with expanding foam and bits of rubble with all the wooden ledge rotten. There were no ‘spores’ or anything but the brown / black strands seen. Is the window poorly fit as it sits on a lintel in essence? Is this dry rot? Wet rot? Do I need to be concerned? How would be best to fill in the gap properly?