Condensation & staining

Bedroom closet had an old moisture stain & the fireplace flue had evidence of condensation. What is the cause of the condenstion.

It is a wood fireplace with a metal insert. There was an exterior vent as well and it was blocked with yellow jacket nests.

The exterior chimney for the fireplace is the metal one. Is the rust staining typical or does this indicate a potential problem?



84906 Medina 008 (Small).jpg

84906 Medina 020 (Small).jpg

84906 Medina 021 (Small).jpg

Hi to all,

Dave the cause of the condencation would appear to be the hot vent pipe running through a colder attic space, is the moisture stain directly below the flue?

Alternatively they could just be leaking flashings.



I’d go with the leaking flashing. The water staining is fairly large & there appears to be a distint water line on the metal flue. Doug