Two 1-1/2" vents serving where a 2" vent is required

Users who are viewing this thread


New Member
Reaction score
I'm venting a bathroom group (sink, toilet, bath/shower) and the rough in location ended up placed directly below a truss, which means I can't take the 2" vent directly up and out. I'm working with a 2x4 stud wall and need to bore through several and make a turn to avoid the truss. Is it code-compliant to run two 1-1/2" vents instead of a single 2"? or is a 2-1/2" bore acceptable in a 2x4? These are non-load bearing walls.

Based on DFU counts, a single 1-1/2" vent should suffice, but I understand code requires a 2" vent for toilets regardless of DFU (toilet is roughed in with 4" pipe).

Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks