Why are these yellow spots on forming on ceiling?

The problem is occurring on the ceiling of a 20 year old house. There are small circular yellow spots ranging from the size of a quarter, to a cup holder size. They have been forming on the ceiling between the first and second floor, as well as between the second floor and the attic at random. Sometimes they form two spots, when they do they're always evenly in line with each other, but they could show up anywhere in any room. Some formed a few years ago, and now some new ones have formed this year.

We think it may have something to do with humidity. It has been a fairly hot and humid summer, and we've had some pretty cold and nasty winters lately. But the circles only seem to form in the summer.

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  • c c
    Lv 7
    1 decade ago
    Favorite Answer

    Could be that the nails used to anchor the ceiling product or the nails in the crossbeams are rusting. The humidity is causing the rust to leach into the ceiling product. Since you say they are in a line, this makes sense.

    The only thing you can do is to prime over them and repaint.

  • 1 decade ago

    These yellow spots are water stain spots. There is water getting in to the upper floor ceiling from the attic. The yellow spots on the 1st floor ceiling could be older stains bleeding through the paint or from the bathroom, or from someone spilling water, etc. I don't think humidity has any thing to do with this. If it did, then everyone would be complaining about yellow spots and humidity. Right? You mentioned that summer brings them on? Rain. Do this. The next time it rains hard, have someone go in to the attic with a flashlight and look for water leaks. The best place to look would be above the yellow spots and on a roof truss as this is where the rain water usually drips from. Once the drip is located it can be backtracked up to the roof sheathing; usually the rain will seep in through the crack between 2 sheets of sheathing. Once located, mark with a crayon/marker. This will get you in the general area on the roof. Water follows the easiest route like this: down a roofing nail, along a crack, over to a truss and drip, drip, drip. Once the leak is found and corrected the yellow spots on the ceilings can be covered with "Kilz". A regular paint will not work. Good Luck!

    Source(s): Handyman 35 yrs
  • 4 years ago

    Yellow Stain On Ceiling

  • 1 decade ago

    The spots are from some degree of moisture. The yellow or brown stains are created when the moisture dries and leaves the minerals behind, thus leaving a stain. It's a sure sign that you have a water leak or condensation is building-up and dripping. If it is a water leak, find it and secure it. Condensation build-up is due to a lack of air flow. A fan or vent could solve a condensation problem.

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  • 4 years ago

    elementary: partitions are less warm than air and steam. Steam condenses on the partitions. i assume it is particularly chilly on your bathe. you like an exhaust fan. Or a bathing room heater, heat up the room till now you're taking a shower and it is going to decelerate the condensation. Exhaust fan isn't of lots use if the bathing room is closed up tight. pass away the hollow interior the door so air gets pulled in from the place of abode, is going interior the direction of the bathing room and gets sucked out by potential of exhaust fan.

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