Converting from single to double sink.

[Matt Gerecke]

Hi There, I am adding a second sink and have opened up the wall behind the existing vanity to see what is behind before I start tearing everything out. From what I can tell, the sink vents directly up into the attic where it ties into the rest of the plumbing vents. My thought was to install a sanitary tee below the existing tee and running it over to the second sink. My question is, do I need to add additional vent pipe on the new sink or can I drain into this and utilize the existing vent configuration?

 

[John Gayewski]

You can add a second tee. You don't need a vent as long as the pipe isn't longer than 42" (going from memory).

The issue would be height. Make sure your new pipe doesn't penetrate the wall too low for your taste. You also can't change elevation when you do this.