Water Stains. Everyone has some sooner or later. Usually on the ceiling and this is a common time of the year (February) to notice one. They can be caused from several different problems. A leaky roof or ceiling vent. Condensation problems, plumbing or venting issues, etc.
Once you have identified the cause of the problem and corrected it, it is time to fix that unsightly stain. You want to make sure the stain area is dry and that there is no damage to the drywall or as the case might be, the plaster. If the area is dry and undamaged, you will want to protect the area (floor) or surrounding wall from over-spray. The best sealer to use is BIN.
I like to spray two to three light coats over the stained area, making sure each coat is dry before respraying. If you happen to have left over or know the correct ceiling paint (If it has been painted) you can repaint only that small area. If you don’t know if it has been painted or don’t have any leftover ceiling paint, by sealing it you have greatly reduced its appearance and can wait until you have time to repaint the ceiling or of course you can call in a professional to do it for you.