Sorry to see and hear about this, and for what its worth I'm neither an insurance agent or a lawyer. I imagine it may rest with the nature of your agreement with the building owner. If its a friend or family that allowed storage for free, then its on you. However, if money exchange hands for storage, there must be some good faith effort on his part to ensure it is solid against normal regional weather Not a tornado, nor a super heavy snow, so "act of God" may not play a part. If it were me, I'd talk to them first, see where they stand on it. Maybe his homeowners or Business insurance would cover it? Doesn't hurt to ask, hopefully any damage to the 27 is minor. First would be to get it out and inspected, hopefully he can shore it up well enough to get items out to rebuild building. Good luck, hoping for a positive outcome.