toilet vent running horizontal

[alainmax]

Oh and another question...:

building a bathroom "upstairs". Can the toilet vent run horizontally ( slight incline ) for 15-20 feet BEFORE going vertical and into the roof??

I could then, possibly make a T in the vertical portion of the tub vent and have only one hole in the roof.

on the same floor i will have shower and 2 sinks as well (

in the same room)

thank you in advance for your input

[phishfood]

Under International Plumbing Code, the vent must be at least 6" above the rim of the toilet before it can be installed horizontally. So if you mean that the vent will be run horizontally in the ceiling of the floor that the toilet is used on, the answer is yes. If the vent will run horizontally in the floor below the toilet, then the answer is no.

[alainmax]

thank you phishfood.

it would be on the floor below the toilet so it would be no !

OK, what is the max distance before it goes up vertically then?

I could make it happen by using the wall behind the toilet, so short horizontal ( may be some incline) then vertical behind the wall ( there is room behind the wall). i suppose like any toilets out there !

[Caduceus]

Yes. Stack vents and vent stacks can be installed as you described. There may be some areas that still frown upon the design, but those restrictions were intended for cast iron stacks.

[Caduceus]

Sorry, phish, I was posting at the same time that you were.

[phishfood]

Once again, codes may differ.

But in my area, it cannot run horizontally at all. Horizontal is defined as an angle more than 45 degrees from the vertical. So, the vent can actually run on a 45 degree angle and still be considered vertical.

[Caduceus]

I kind of pictured what alainmax described as being similar to a horizontal branch with a wye to the toilet and continuing to the wall where it goes vertical as a stack vent. So, alain, you have experienced the differences in codes through online forums. It's fun and educational.

[alainmax]

thank you both

i think i will use a 3x2 reducing Y and a 45degree street elbow going in opposite direction of the drain, running next to the closet bend into the wall behind the toilet then straight up.

The drain will run "in front" of the toilet and hooking in to the main 3" drain in the soffit ( room below)

[Another-Plumber]

anything that is above the flood line will work

[alainmax]

In a bathroom, is 6" above the sinks rim considered flood line?