DIYbanter - View Single Post - venting bath fan to outside from attic...

writes:

I'm in Chicago, where we should have better than R 38 up in the attic.
Winters get very cold. Because of this, I don't EVER run the bathroom
fan, but instead open a window in the summer, or keep the bathroom door
open about 6" in the winter, and keep the HVAC fan on, instead.

I'm in Chicago too. When I purchased my current home, my inspector
noted the bathroom vent situation and told me I'll want to fix that
post haste. I ddi. I have R40 insulation in the attic. I do run the
bathroom fan to remove the moisture from teh living space and
eliminate moisture mold needs to grow.

someone I know suggested venting the bath fan into the plumbing stack.
I'm wondering if that would be a code violation or not...
The stack does vent out the roof! :-)

Big heaping steaming code violation. :-)

Tapping into the stack to your exhaust fan is an excellent way to have
your exhaust fan become a nice conduit for sewage gases to get into
your living space without a P trap sealing it off.

Look in the yellow pages for ventilation folks and have someone come
out and install a roof cap and get it fixed correctly...and consider
using your exhaust fan to get that moisture out of your place. With
the liability mold has become, the last thing you want is to give
buyers any reason to freak out about the possibilities more htan some
already do.

Some of the same folks who insulate attics do this sort of work of
installing roof caps.

--
Todd H.
http://www.toddh.net/