We are wondering whether we have a problem which needs to be looked at or if this is just normal aging. The situation is that we just recently noticed light stains on the ceiling where it meets the exterior wall for each joust. The stains look like a light mark about the width of the joist for about 12" long. They also appear right at the beak (the ceiling is a vaulted ceiling) again equal in length on both sides of the peak for every joist. The house is 15 years old (built in July of 87) and the ceilings have never been repainted.
Also we have just recently noticed that on the outside walls we can see a number of the nail or screws which are not showing up as nail pops where there is a bump on the wall but rather it looks like a little stain just like on the ceiling. We could not find any similar marks on interior walls. The walls have not been repainted in around 8 years.
Also we have noticed that some of the outlets have a dark film around them. When I removed the cover it looks like it accumulates around the openings in the cover (around the outside, around the light switch opening or receptacle opening). The substance is very fine and black which when you touch it leaves a black mark on you finger which you can't just rub off, it does come off with water.