New bath lavatory venting

[TylerP]

Hello,
I am adding a toilet, shower, and lavatory to my unfinished attic space. The current vent stack for the main level fixtures runs out the roof right above the main level bath (maybe 6 inches above the attic floor). Since that is too low and not worth the trouble of tying into, I am going to run a new 3" waste line to the basement and tie in to the main line that goes to the city sewer.

The main reason I'm asking for advice is because the the lavatory I'd like to install is on the other side of the attic from the new 3" waste line and I don't know best how to vent it. The attic has a 12:12 pitch ceiling and the two side walls have a door and a window that would block the vent lines. I guess what I am asking is: can I take a vent up from behind the vanity, along the 12:12 ceiling, across the flat section of ceiling and then back down the oposite 12:12 ceiling and tie it into the new 2" vent for the new toilet and shower? Can the vent go up and then back down before going out the roof? Check out the rough sketch below.

Thanks for the help!

 

[Dj2]

"can I take a vent up from behind the vanity, along the 12:12 ceiling, across the flat section of ceiling and then back down the oposite 12:12 ceiling and tie it into the new 2" vent for the new toilet and shower?"

Vents in the attic can only go up or flat in certain circumstances, like bypassing an obstruction like a window. The main reason is the possbility of condensation in the vent.
Check your local code about venting and distances for flat vents.
Best to find a way to vent the sink thru the roof with its own vent.

 

[Sponsor]

 

[Cacher_Chick]

With your layout, it makes good sense to install the vent for the sink straight up through the roof.

 

[TylerP]

Yeah, I thought about venting it on its own straight up and out, but don't want a vent to be see from the street. and less holes I cut in the roof the better. Oh well! Thanks for the insight.

 

[Michael Young]

Hello,
I am adding a toilet, shower, and lavatory to my unfinished attic space. The current vent stack for the main level fixtures runs out the roof right above the main level bath (maybe 6 inches above the attic floor). Since that is too low and not worth the trouble of tying into, I am going to run a new 3" waste line to the basement and tie in to the main line that goes to the city sewer.

The main reason I'm asking for advice is because the the lavatory I'd like to install is on the other side of the attic from the new 3" waste line and I don't know best how to vent it. The attic has a 12:12 pitch ceiling and the two side walls have a door and a window that would block the vent lines. I guess what I am asking is: can I take a vent up from behind the vanity, along the 12:12 ceiling, across the flat section of ceiling and then back down the oposite 12:12 ceiling and tie it into the new 2" vent for the new toilet and shower? Can the vent go up and then back down before going out the roof? Check out the rough sketch below.

Thanks for the help!View attachment 44624

Just studor vent it right under the sink inside the cabinet and be done with it. Don't over-complicate your life (http://www.homeservicestriad.com/)