When we first moved into our house, one of the bedroom walls (adjacent to an attic)started to "leach" in the winter as the temperature drops.
The "leach" visually looks like long drips running from the top of the wall to the bottom. At the bottom of the drip sometimes an "oily" like substance can be felt. This has been ongoing every winter for the past 12 years. The wallboard itself is structurally sound as is the paint surface.
The rest of the walls in the room are fine. And the wall that is leaching is colder than the others.
Any thoughts on what this may be? Thanks