My laundry room and powder room are connected to the same vent. When the washing machine drains, the sink in the powder room gurgles. I decided to remodel the laundry room and put the pipes in the wall. Lo and behold, there is no vent for the drain – that’s my gurgling problem. My problem is now where do I run a vent? I can’t go straight up, that runs into the middle of an upstairs bedroom. Going inside an outside wall would be a huge pain – I’ve have to knock holes in the plaster walls in the bedroom above. Can I run outside and up the outside wall to the roof? Thanks for a reply!