If there is plumbing problem that happens inside the wall structure mold will grow from the inside and slowly spread to the outer part if not removed.
Brown mold spots on ceiling.
To test for mold touch the spots with a cotton swab that has been dipped in household bleach.
The outer surface is not the only place brown mold can grow.
Mold is often dark but it can come in other colors.
Some species of brown mold may even grow into thicker mushroom like blobs.
Mold damage aside from water damage mold growth on your ceiling is also a likely cause of the brown spots.
How to safely clean mold off of a ceiling.
Typically your only recourse is to repaint.
Cleaning soot from ghosting is extremely hard.
When a portion of the ceiling stays damp for an extended period of time a yellowish brown mold stain can form overhead.
In this case it was due to areas of missing insulation in the attic.
Once mold shows up on your ceiling it isn t long before a small patch evolves into a thriving colony.
If left unchecked brown mold can grow thicker taking on a fuzzy or even hairy appearance.
It may not have been mold.
In early stages brown mold may look like spots or discolouration.
I suggest you call an exterminator.
We had a wasp problem a while back and the exterminator asked if there were any brown spots on the walls or ceiling explaining that this is a sign of infestation.
Walls are also common habitat for brown mold to grow especially in damp or dark spaces such as ceiling room and basement.
Mold may not seem very threatening but the danger.
Brownish spots on the ceiling can be fluids gross i know from the bugs.
There are 3 most common types of ceiling stains and they are 1.
The spots also may be mold.
The soot attaches to cold spots on the ceiling.
Ceiling stains can draw eyes away from even the most beautiful living room dining or kitchen.
The second cause of ceiling discoloration may be related to moisture but is not directly caused by it.
Left untreated the mold stain may grow and become darker over time.
Depending on the colour of the surface it is growing on it may appear brown or nearly black.
Your best option for a base coat to cover water stains on the ceiling is an oil based mold resistant stain blocking primer in a shade closely matching that of the existing ceiling.