Bathroom ventilation and adjacent plumbing stack vent

I took the attached pictures yesterday and was wondering if anyone had ever a bathroom fan vented through the sidewall of a house like this. From what I’ve read, it looks like is a legitimate method and actually reduces the chance of condensation forming in the vent and rolling down the duct. However, I do have issues with the way it is secured. It looks like a new roof was put on a few years ago and this was re-routed out the side of the house at that time. Adjacent to this vent termination, there is another roof stack vent that has a towel wrapped around it and a metal pan beneath, but it doesn’t appear that this has been an issue since the new roof was put on and new vent stack boots were installed. On the outside they have used a dryer vent cap to terminate to the exterior.

Sidewall terminations are common and perfectly acceptable, however, they should be sealed properly - not like you have pictured.

Exactly Jeff.



The fan duct should be sealed at all joints and have a vapour barriered insulation jacket installed.

By the straw, it looks like some bird had nested near the wall. I have seen where starlings had pecked through the cheap plastic “dryer” type ducting and nested in the attic. Metal duct is the way to go.

Last year, saw one $500,000 home where birds had nested in 2 bathroom fan ducts.

I agree, but I further recommend the pipe be insulated to prevent condensing in the attic.

Nice link Marcel, thanks.