No this isn’t a joke : ) I recently remodeled a bathroom and installed a shower fan that vents to the outside. About a month ago, or a year after completing the bathroom, there is a horrible odor (i.e. rotting flesh) whenever the fan is turned on. There is also a slight smell when it rains heavily. I thought that there must be a dead animal in the attic, but there is no evidence of one. The attic is spotless, odorless and all gable vents are screened to keep the varmints out. I had a clear view of the fan unit inside the attic and everything is in excellent condition including the flexible duct which vents to the outside. About five feet adjacent to the duct is the stack vent which is connected to the septic system waste pipe. I thought this might be the problem, but how could it be if the fan is pulling air out of the house. The stack vent is original construction. I’m totally puzzled and I’d be interested to hear your thoughts. Thanks.
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How long is the flexible duct? Perhaps water has condensed in there and stuff is growing.
Al Mollitor, Sharon, MA
It's about four feet long.
My guess is the fan is creating a slight vacuum in the bathroom and drawing "make up" air in from whereever presents the least resistance. In this case it may be drawing air in from the crawlspace through any penetrations in the sheetrock (elec boxes, plumbing, etc) and the bad smell may be originating under the house.
Usually attics get hot enough this time of year that dead animals dessicate to the point of no odor relatively quickly.
Another possibility is the toe kick area under the vanity???
Good Luck and keep us informed
Karl
That was my thinking. Mice love to nest under sinks in that crawl. They can get past the trim rings on the drains and supply. One died and the fan sucks air past his furry little corpse into the room so that when grampa uses the potty, everyone has new reason to say, "Phew, What died in here?".
Excellence is its own reward!
I seal all my pipe penetrations. Nobody knows it but I do and that is enough!
What do you seal them with?
First of all I drill all my DWV holes fairly close to the pipe OD size. Then I silicone them to reduce banging, creaking, etc.
On the water lines I drill everything 1 3/8" then use insulators which I then silicone around before I put the escutcheon down.
Rodent proof? nope. never claim that. but rodent resistant? you betcha.
I rarely use my sawzall to make holes. Only for big stuff like under a tub for the drain, etc. If in a joist space I then box in that area and foam all the cracks. If in a slab I seal the area off with foam.
God bless you man,
A plumber who does not believe the recip is the only way to make holes.Never be afraid to try something new. Remember, amateurs built the ark, Professionals build the Titanic.
they are for cutting PVC on my jobs
would you kindly ship some of your apprentices to KS?Never be afraid to try something new. Remember, amateurs built the ark, Professionals build the Titanic.
nope. they are my "babies" I am demanding of them but pay them well and treat them like gold.
say... I have been to KC at night. some pretty good joints in some industrial area. had a ball
The vacuum effect makes sense. It seems like it could be a mouse, but I would have expected it to dry up by now. I'll let you know if I ever figure it out for sure. Thanks.
OK....How about this?....One of the drains is not properly vented and the trap get siphoned out. When you turn on the fan, sewer gas is getting sucked into the bathroom.
Al Mollitor, Sharon MA
Well, it smells like a dead animal or sewer/septic gas, that's for sure. During the remodel, none of the plumbing was changed. The supply/drains were capped until the new sink was installed. So I would think this isn't the problem since it only started about a month or so ago.