Have I correctly laid out bathroom venting?

We are planning to remodel a small single bathroom in a one bathroom home. A roof deck/framing above the room greatly restricts where we can run vent pipes. I have no way to run vertical vents from the soil stack, shower, or washer. The length of run from the water closet to sewer connection is less than 11'.

Do I have proper venting with the single 3" dry vent as shown?

Can I use a single 2" dry vent instead of a 3"?

The only other existing plumbing is a single kitchen sink with a separate sewer connection on the other side of the home. I cannot run the bathroom drains in that direction.

Thank you very much--Jim Herold

Pretty much nothing is properly vented there. Need to know distances of horizontal branch and branches. Flat vent behind the toiler is a no no. None of the other fixtures are vented at all.

I've added dimensions to my drawing which should be accurate to +/- 6".

The center of the closet flange will be 15" from the wall. I planned that the closet would drain into a 3" Sanitary Wye. The 3" vent line shown would connect to the dry end of the Wye, would slope uphill to the wall at 1/4"/foot, connect into a 90 degree elbow and travel vertically through the wall and roof.

The lateral from the lavatory would pass through a 1 1/2" X 3" long sweep fitting into the 3" line a point approximately 6" below the Sanitary Wye for the water closet. The 2' vertical dimension shown is the drop from the lavatory P trap into the lateral line below and the 4' lateral dimension is the distance into the 3" line.

The 2 1/2' dimension shown on the 3" drain is the distance between the long sweep fittings where each of the lavatory and washer join the 3" drain.

The vertical dimension shown for the washer is the height of the standpipe plus what it takes to clear the floor joists and join the lateral drain.

I hope the rest of the downstream dimensions are self explanatory.

Thank you very much for any advice. The restriction on vent options because of the overhead deck has been a real challenge for me. I really only have the small wall area behind the water closet to run a vent line. That's why I show a single 3" vent positioned where it is. The obvious question is what do I need to do to make the layout work?

My updated drawing, visible to me in my Preview, did not come through.

I will attempt to include it in this reply. I will start a new thread if the update is incomplete with this second attempt.

Jim Herold

You still have no fixture vents and the vent you do have, besides having a flat section behind the toilet that will eventually plug up, is doing nothing at all. All of the fixture traps must be either wet vented or individually vented depending on their distance from the wet vent. I think that at this point you really should hire a licensed plumber before you get into trouble here. What you have drawn will never pass inspection.

vents

You not only do not have proper venting, you do not have ANY venting, and the dimensions are immaterial. They could be 1" or 50' and their would still not be any venting. That is why most remodelers decide to use plumbers who know what they are doing, rather than cobble something together and then have to tear it all out and start over.

Here is a totally different vent design that will fit within current floor, wall, and roof framing. Vent lines are shown as dashed.

Does this design provide appropriate venting?

If yes, should the vertical vent pipe through the roof be 2" or 3"?

If no, is what change(s) should I make?

Thank you very much--Jim Herold

hard to tell but here's a few venting rules. No part of the vent may run horizontally until it has risen 6" above the flood level rim of the highest fixture served. All vent connections to horizontal branch or mains shall be at a 45 degree from the horizontal center line and shall rise vertically untill 6" above the flood level rim of the highest fixture served. Most places require a roof penetration to be a minimum of 3" with 18" above the roof.

I do not know your exact layout with wall locations but maybe this will help you out.

Thanks to each of you for your responses. You are definitely helping me.

A couple of points of clarification:

At the top of my last drawing, I ask about a 2" or 3" size. I was trying to ask how to size the diameter of the vent pipe, not how far it needs to penetrate above the roof.

Related to this, even in my very first design, which was assessed as having no venting, I intended that the vent coming out behind the water closest would be a full 3" vent traveling vertically through the wall and out the roof. I also intended to slope it at a 45 degree angle from the water closet Wye to make the short run back toward and into the wall behind the water closet. I did not mean it to be a horizontal vent. Hopefully this clarifies my initial drawing.

In reference to the layout just posted by C Numb: His question about the wall location is exactly why I am struggling with this design--the only wall I have available for vertical venting is the wall behind the lavatory and water closet. All other walls and overhead areas are "blocked" because of an overhead deck which I can't penetrate with any plumbing. Following his suggestions would have vent pipes coming through my deck.

That is why my last layout resorted to a 2" vent line that rose from fittings in the shower and washing machine laterals and then ran back to the wall fitting that I depicted as point "A". That vent line would be at a slope of 1/4"/foot and the total length of the run would be about 3 1/2' before going vertical at the fitting in the wall. However, that design clearly violates the principle posted by nhmaster that no vent line could run horizontal until rising vertically to a level 6" above the flood level rim of the highest fixture served.

I really appreciate your help.

Jim Herold

I will need to see a floor plan. Just another thought: you could drop and box out the vented lines along the wall close to the ceiling over towards the lav before going thru to the next floor...

You may have just provided my breakthrough!

Talking from your drawing--I think you are saying to consider dropping and boxing in the horizontal vent line shown in your drawing as 1 1/2" between the shower and washer and then as 2" over to the wall. Is that your suggestion? If yes, I can do that.

Then, staying with your drawing--I understand that I do not need a separate vent from the Water Closet. Correct?

And, a single 2" vent pipe up inside the wall and through the roof, connected as you show, will be sufficient to vent all the fixtures. Have I got that right?

If you confirm that I have all that right, I can make that work.

Thank you very much--Jim Herold

As far as I'm concerned what I have drawn would work fine. The water closet is vented by the lav, but in some states they want every fixture vented, even if it means dry venting. Anyway, glad to help ya out.

But, even in that case, I could run a 2" vent line off the water closet Wye and connect it up in the wall with the vent setup you drew. Then, I would still run the 2" line out through the roof--right?

Jim Herold

yea, but you should not have to do that. If you want take my drawing to the building department to see if it would pass. I know it would fly though any inspection in my state.

vent

WE are working at a disadvantage because we know NOTHING about your room or its construction. If we were there, laying out the venting would be simple. Trying to do it with your description is almost impossible. The "highest point" for the shower and washer would be the top of the washer's standpipe, and the two vents could not tie together until they were 6" above that point, at which point they could also go horizontally.