I enjoy watching Sherlock Holmes movies and I enjoy having to do a little detective work during an inspection. This one, however, did not require much deduction. You know there's a problem when you walk into a basement and see this:
No that is not a new kind of Faux finish. It's mold! Wall to wall mold. Here's another look at it:
It did take some effort (mostly physical) to get to the cause. I knew that there had to be moisture for the mold to grow, but it wasn't some elusive source as I had hoped. This was obvious once I stepped onto the soggy shag carpet.
Systematically going around the exterior, I found this drain:
Which collected the roof water and runoff into this broken drainage pipe located in a crawlspace next to the basement:
The water was then deposited into this trench running along the basement wall:
Yes lakes are nice, but it's not a good idea to start one under your house.