Ceiling with fungi/mold spores

[JIM MURPHY]

Older house, 1963, that had one room that was covered with mold/fungi spores in the ceiling. The closer to an exterior door the more prevalent it was. Cause?
( 1st story room over a crawl space in a two story house)

Jim

[Rick Cantrell]

If it was mold, water is always the cause.

[JIM MURPHY]

No leaks or water stains

[Rick Cantrell]

There either IS moisture, WAS moisture, or it's not mold.

[CHARLIE VAN FLEET]

JIM

pictures always helps on this site--got any

cvf

[John Kogel]

Lack of heat, so a cold surface, and moisture, maybe from the crawlspace, maybe through the door. Or some other source of moisture, like a person breathing gives off moisture. All it takes to prevent it is bit of heat and air circulation.

[JIM MURPHY]

Sorry, I do have pictures

[Garry Blankenship]

There either IS moisture, WAS moisture, or it's not mold.

An Amen for Rick. No moisure, no mold, ( was and is aside ). Hope you have a respirator. Correction; that would not be mold, but "organic biological growth".

[Raymond Wand]

Have it tested to ensure it actually is mould.

[Lon Henderson]

Usually..........when I see that kind of mold-like substance on a ceiling, it is associated with some source of high humidity from inside the room. Maybe a past occupant had several aquariums or a room humidifier cranked to high.

[Ian Page]

GrowLab or other horticultural endeavors?

[bob smit]

Closer to exterior door = closer to exterior wall = ice dam?

[Lon Henderson]

My additional two cents is that if my scenario of high humidity inside is correct. Then it would make sense that there would be more mold near the door. Whenever the door is opened, cold air comes in and cools the ceiling near the door. More condensation occurs on the cooler area and hence, more moisture to promote the mold.