If water is dripping or the spot feels wet, set a bucket or towel under it and move furniture and rugs out of the way. Standing water on drywall can bring a whole section of ceiling down.
If the drywall is bulging and holding water, poke a small hole in the low point with a screwdriver and let it drain into the bucket. Draining it on purpose beats a surprise collapse.
Go up and look for wet insulation, water tracks on the rafters, or daylight coming through the deck. Note where the wet wood is. That tells the roofer where to start.
Take a picture now and again in a few hours. If it's spreading, that's useful for your roofer and for an insurance claim later.
Most ceiling stains in St. Louis homes come from a roof leak, not a plumbing pipe. Water finds a gap around flashing, a cracked shingle, or a nail that backed out, then travels down the rafters and soaks the drywall wherever gravity takes it. That's why the stain can sit six feet from the actual hole.
Our older neighborhoods make this common. Century homes in Soulard, Lafayette Square, and Tower Grove often have flat or low-slope sections and aging flashing that our freeze-thaw winters work loose. A roofer checks the flashing around chimneys and vents, the valleys where two roof planes meet, and the shingles uphill from the stain. In the attic they look for the entry point where the wood is dark and wet.
Treat it as urgent if the stain is growing while you watch, if the drywall sags, or if it shows up right after a hard rain or hail. St. Louis storms can peel or crack shingles in minutes, and a small opening lets a lot of water in fast. Waiting a week turns a shingle repair into a soaked ceiling, ruined insulation, and mold in the framing.
We come out the same day across the metro, from Kirkwood and Webster Groves to Florissant and Ferguson. If the roof is still leaking, we can tarp it over to stop the water, then find the real source once it's safe and dry to work up top.
Describe what you're seeing to a real St. Louis roofer: call (314) 555-0149 or send the form. Free, no obligation.