This is a new one for me.
We found an adorable ranch home for a buyer of mine. (No... that's not the new part!) During the inspection, we also found a great deal of mold in the attic. Every surface in the attic was covered with a grey beard. Now usually with homes like that we find a bathroom venting into the attic, raising the humidity up there, and causing all that mold. Nope... the bathroom was vented through the roof.
We guessed (the inspector and I), that perhaps at one time the bathroom vented into the attic... as the roof appeared to be about 8 years old... maybe at that time they corrected it. No real way to tell, I guess it'll remain a mystery, but we contracted for a mold remediation company... and my buyer went forward.
They have since moved in, and heard an interesting story from one of the neighbours. A few years ago the owner had the house rented to a lovely young couple with 2 children. At some time during their lease, they had about 16 people living in this 3bedroom house for about 3 years. The owner was an out-of-state owner, so they didn't know. Of course the neighbours did. The matriarch of the family spent all of her time in the kitchen always having a pot, or two, of something boiling on the stove to feed the 16 people.
In addition to that, they owned a Guinea Hen (yeah, I had to look it up, too... see the picture) who roamed the neighbourhood. (and no, the neighbourhood is not zoned for fowl).
So... our forensic real estate is now figuring... with 16 people in the house... that's got to mean at least 10 hot showers per day... constant pots of boiling something-or-other steaming on the stove all day... and a Guinea Fowl, the place had the humidity of the Amazon rain forest, much of that humidity making its way into the overwarmed attic.