An Amityville Moment Is Happening Upstairs With Mysterious Gooey Stuff.....

[Mosaic]

....dripping out of the bathroom vent. Can this be puree of pipistrelle?

[murraymints]

is it smelly ?

[Tilly2]

I do hope not.

[Mosaic]

Not smelly - dark rusty brown in colour.
Fan refused to turn first thing - then started up all of a sudden.
Then the dripping.
The cat avoids it.....I'm going to have to get up there with a torch.

[Mosaic]

Been up, poked around, mopped it up.....no legs or body parts visible.....poltergeist then. Just a tiny one.

[buildersmate]

If the fan feeds into a length of ducting that takes the stale air somewhere to vent, it is very possible that the warm and moist air from the bathroom is being condensed in the ducting, the water (complete with brown non-bat gunk from previous extraction) is dripping back down the ducting into the fan and out.
It's the cold temperatures doing it - solve by insulating the outside of the ducting with fibreglass, if you can access it.
(Clearly this possible explanation doesn't apply if you are extracting straight out the window)

[Mosaic]

Thanks Builder - it vents out through the roof space to the outside, so at some point I will crawl up there with insulation.
What you say explains the absence of dead critter, but I can't fathom why it's never occurred before - we've had far colder winters in times past and it's been there for 25 years.
Probably an odd wind direction combined with DIL taking long steamy baths....

[buildersmate]

Mrs Mosaic afforded herself the luxury of an exceptionally long shower this morning?

[Mosaic]

Builders....there is no Mrs Mosaic......there is a Mister.......I'm a gurlie......with me own goggles.