Not sure if this question is better suited in this forum, or in the "Walls and Ceilings", but I'd appreciate any feedback. First off, to paint a clear picture of the issue, we live in a regular 1,000 sqft rectangle-shaped brick ranch house. Over a year ago, we noticed some gray-ish places appearing on the outer edges of our ceilings, in every room along the front side of our house, and in one of the rooms on the back side of the house. By outer edge, I mean the side of the ceiling closest to the guttering that runs along the front and back of the house -- just to give you a visual. These gray/shadowy looking places have no particular shape, they vary in size, etc, but just sort of look like gray blobs. We just had a new roof put on 3 years ago, so a leak or some sort of moisture issue from the roof was the last thing we suspected, and we were right. The roof is just fine - no issues there. Then we had a couple of different contractors come out and take a look (wasn't sure what other kind of person you call to come and check out this kind of thing???), and they said that in the attic, directly above the places where we had "shadows" on the ceiling, the insulation (it is blown-in) looked as though it had somehow been moved out of the way or displaced. We have no idea how this could have happened. Anyway, they said that's likely the reason why we are seeing this places on our ceiling - due to lack of insulation in those specific areas. So, we pushed the insulation back into place as best we could, and have tried to wash off the areas in the ceilings as best we can. Some of the gray does come off when scrubbed. We are going to prime it and paint it and hope that it doesn't come back. Our main concern is this: While we were in the middle of trying to figure out what in the world was causing these shadow places on our ceiling, we also did a do it yourself mold test kit in the attic. The test came back positive and mold grew in the petri dish. This is of great concern to us, even though we can find NO visible mold and there is not a musty/moldy smell in the attic. We would like some opinions as to whether or not enough condensation could occur, in an issue such as this with insulation, that would enable mold growth. We cannot understand why the mold test came back positive yet we cannot find any in the attic. There's a vent in the attic on each end, plus an attic fan, so it is very well ventilated. Any thoughts/suggestions, etc., are welcome. Thank you.