So 5 years back I bought my house in Montreal and the inspection showed that one of the two 2nd floor bathrooms was just venting into the attic. So after trying for a long time to get a roofer to fix it (no one was interested or would even show up) I did it myself. I installed a 4” vent (similar to https://www.homedepot.ca/product/gaf-master-flow-4-inch-galvanized-goose-neck-vent-black/1001090038). Yay. Fast forward to March and the vent is causing crazy ice dams. What can I do to prevent this happened this year?
It actually got worse than this. This is the area directly below the vent
Edit: I should mention I have another bathroom that vents into a more cylindrical vent a few feet away and it doesn’t seem to cause any issues. I just can’t seem to find any of these vents.