The willow tree dropped a limb through the Paymaster’s Office. Fortunately, there is some extra slate in the barn, so they can patch the roof. It’s ironic that the building that was most neglected is in the best condition. I know the answer is water – it never had plumbing, so it never had water damage. The only indignity it suffered was when Dawn’s brother’s used it for his bachelor pad.
(By the way, it’s called the Paymaster’s Office because that’s where the Paymaster sat. A wall splits the room in two, with a small window where workmen would collect their wages. From the basement you can see where the floor was reinforced, presumably to support a safe above.)