How can I tell if my bath exhaust fan is vented outside ? ?

Question

I am getting mold on the ceiling even when the fan is run and I am starting to wonder if the fan is vented correctly . I do not see a vent hole on the out side wall just a pipe on the roof that I think is just a plumbing pipe.

The house is 50 plus years old and had a fan when we moved in we had a contractor change it with a new one . And there is another bath right above this bathroom that has a fan too that seems to not work well. Could the air just be moved to the floor/ceiling between the two baths by the fan making the problem with the mold worse ?

Answer 1

Mine is vented to the basement. Have you checked for that? We had a very bad mold problem also. I washed the walls with ammonia (it kills mold and mildew if you use it straight and almost killed me too!) I scraped, primed and painted with mold resistant paint and the problem hasn't returned in the two years since I did.  By the way that pipe is plumbing ventilation.

Answer 2

The fan vent should be flat with flaps that open when the fan is on and close when the fan is off. They are usually located on a outside wall. You should verify that it is not vented into your attic as that can cause some serious moisture issues. You can take the cover off the fan and check to make sure there is not some build up on the fan blades as well.The pipe on the roof is you plumbing as all components of plumbing are NOT UNDERGROUND as plumbing needs to be vented to release methane fumes and plumbing also needs to be vented to operate (one of the key aspects of modern day plumbing).  

Answer 3

My father had a roofer that removed the vent and roofed over it. It wasn't until the drywall in the ceiling all started to mold that we figured out it was blowing between the roof and the ceiling.

The pipe on the roof is likely the plumbing vent. It for the sewer gas and to provide air so water can drain.    

Answer 4

have a freind blow cigerette smoke in it while its on as you are outside watching for smoke,,,, got a smoke friend?

Answer 5

the vent would probably look flat. The pipe you see is the vent for the plumbing, so I guess its NOT vented to the outside

Answer 6

yes that pipe is the fan...plumbing is under ground...just leave the fan on longer till the windows are dry and it feels comfortable in your bathroom then turn the fan off!

Answer 7

you MUST vent the fans to the outside of the house.

if not the moisture is not removed. it sounds like there is no

DUCT work from the fan to the outside.

if there isn't the moisture could be be blowing above the fan and staying in the area above the bathroom.

Or the fan might not be strong enough to push the air and moisture far enough from the fan.