I don’t see it as bleak as the others do. If there is a roof on it, the shell construction can stand dry for 25 years without much happening to it. Ok, probably everything first has to be completely cleared of animals and plants before continuing to build – there are special products for that. With the electrical system and heating, I would assume total damage, but I wouldn’t immediately tear down the walls and the roof. I’m curious what the appraiser will say.