Hey, at least you didn't discover that your garage remodel was actually over a blocked pipe that was sabotaged
by the previous contractor because the former owner treated them like shit. In that case, the pipe was blocked with cement,
peed into 
then plugged with more cement. And positioned under the house area so foundation would have to be ripped up in order to clear the blockage.
That still doesn't top the abandoned, still partly full, and
hidden after being reported as removed, heating oil tank that turned one home-buyer's front yard into a Superfund site.
^-.-^