Years of water damage In rental unit structure, newly discovered

[Taylor Eilers]

Good Afternoon,

Upon replacing a window in one of my rental units, that previously was leaking, severe water damage was noted in the structure was uncovered. It looks like it has been ongoing for a long time (10+ years). Not sure that it goes throughout the unit, but our best guess is that it might. I bought the unit earlier this year and the inspector didn't catch it, I am almost certain that the previous owner knew about it. There is no active roof or window leak currently. I am wondering who has had experience with this and if insurance will generally cover it, and what they will cover? I wanted to get opinions before I notified them. I live in San Diego, so major fixes and rennos are not cheap here. 

Taylor