Exterior water damage
My first time posting a message on this forum. I have an addition, built four years ago, that appears to have some rot at the lower corner of a window, in the T111 siding and the layer of OSB behind it. I noticed it when a recent hailstorm 'punctured' the piece of partially rotted cedar trim covering the damaged area. I removed the trim and checked for termites--no tunnels or sawdust, but there is some 'feathery-pattern' fungus, climbing the wall. None of the three other pieces of trim (on two windows) seems to be affected. Also, there is nothing on the inside to indicate that the damage has reached that far.
My questions: Is there a product that I can inject to saturate the area, to stop the fungus and rot? Can I then fill in the void with an epoxy product, before installing a new piece of trim, then caulk as usual to seal? Should the T111 have been painted before the trim was installed? And, should I remove all the trim pieces and paint the bare wood before this happens again?
Thank you for any help or suggestions.