It depends on how deep the mold has grown.
Ceiling no attic without drywall mold.
Next take a look at your attic.
Purchase an inexpensive rh meter and monitor the humidity levels in the room.
That dark spot on your ceiling may be the result of more than just a ceiling water leak.
How to fix ceiling condensation.
When you have a ceiling water leak there is always the chance that the ceiling may fall due to the weight of the water and the loss of structural integrity in the ceiling material.
How to avoid condensation leaks attic mold insulation mold structural damage to roof framing when roof venting is not possible cathedral roof and knee wall insulation venting air path options in older homes hot roof designs.
Suggestions for un vented or hard to vent building roof cavities.
Applying mastic gum to the duct joints and adding an r6 layer of insulation around your sheet metal ducts goes a long way toward protecting your attic and ceiling.
Under the right conditions mold can begin to grow in as little as 24 hours.
Worries about the hot roof un vented cathedral ceiling designs how to.
If you can use a wide spackling knife and scrape the paint and if no mold shows at the lower layer then you do not need to replace just clean off the mold.
Mold can grow anywhere that there was water damage meaning in your drywall insulation and even in your floorboards and ceiling beams.
Take care of your attic hvac air ducts too.
Condensation on your ceiling can cause water damage and promote the growth of mold or mildew.
Closing in the ceiling too quickly may trap moisture that can foster the growth of mold and mildew.
Excess humidity can also cause mold growth on the ceiling even in a well insulated attic space.
But if after it dries the drywall feels loose or spongy to the touch it should be removed and patched in with a replacement piece of drywall.
However if you find no end to the mold it is likely feeding on the drywall and the drywall needs to be removed completely.
Warm air escaping from a duct into a cold attic can create condensation and encourage mold growth.
The attic floor which is the ceiling of the living space below often already is insulated.
Water soaked drywall often will dry out fine if it gets proper ventilation.
The 3rd potential cause is ghosting which is not actually mold though it can look very similar.