I own a town house and have a small drain (for laundry) located in a
first floor utility room. I am trying to vent my dryer and noticed
(while opening the drywall up to see what I had) the drain has a vent
that goes to the roof (two stories). Its plastic probably about
four-six inches in diameter. Is this for sewer gases or something? Is
that why it goes to the roof? No other drains are hooked up to it,--
unless underneath they all flow into one-- and that is the vent?? I
didnt want to run a seperate vent for the dryer but it looks that way
huh?