We've a two-year seepage issue in our ceiling that we think is related to our 100 year-old chimney. My original assumption was that creosote was leaking through the brickwork due to extreme heating and cooling (the furnace and the hot water heater vent through the chimney) here in WI, causing the ceiling and the plasterwork around the chimney on the second floor to bubble and seep with brown ooze. It happens when it's humid, it happens when the temp changes dramatically. We then paid to remove the chimney down to the floor of the attic, remove the ducting that was in the chimney, and replace it w/PVC. Alas, it's still happening. We've plenty of ventilation in the attic, but we're still getting brown seepage.
Any ideas about what to do next? We've checked our attic vents--all are unblocked by insulation, so it doesn't look like a condensation build-up is the main issue...