We are about to renovate our bedroom by knocking out a couple walls and expanding it. One thing I'm already aware of is the vent stack for the washing machin on the main level runs through this wall. My question is can the vent stack be run horizontally out the side of a house rather than going through the roof? If not, can the vent stack be re-routed through an outside wall (even in a cold winter climate in Canada... I would assume yes as it runs through the attic already which would get very cold in the winter time).
Thanks for your help.

Hi TDK...

Best bet here will be to run it into the outside wall and then connect back onto the old vent just before it exits the roof.

Otherwise, you could run the vent outside as long as you run it above the roof... can't be within 10 feet of a window, fan,skylight, etc.

I'd run it up the outside wall!

Mark

PS... be sure that the vent pitches back toward the drain so that any rain water that enters the pipe can drain back to the sewer via gravity.