Advice on adding 2nd floor bath

[VikkiP]

We just bought a 1950 bungalow with a semi-finished attic and full basement. It could make a nice master suite with the addition of a shed dormer, and adding a bathroom upstairs would really make it nice. Main stack is 3" CI and serves the existing first floor bath only. None of the existing first floor fixtures are currently vented except at the stack.

Given this drawing (sorry for the hijack and poor markup), would this work for venting and draining? All fixtures are within 4' of the stack, toilet is just far enough away for the closet bend.

 

[hj]

NO, but if you are doing this much work on the upstairs, why are you trying to go "cheap' with the plumbing?

 

[Sponsor]

 

[VikkiP]

Not trying to go "cheap" at all. I have to work within a framework of an existing wet wall that has three fixtures in 7 feet of wall, and the bath above will have the same layout as there is a furnace and ductwork underneath the bathroom limiting my options.

I came here for recommendations, would be interested in yours.

 

[Reach4]

I suggest that you edit your drawing to erase the vent and drain lines that you don't intend to have. Alternatively color in all of the lines that you will keep.

You need a vent line brought to the lower floor that only connects to the upper floor vents 42 inches or more above the upper floor floor. That may be what you had in mind, but I am not sure.

 

[VikkiP]

I am good with my hands but artistically challenged. What I intended to portray is that the existing stack would remain essentially as-is, with fixture vents added to this stack above this floor's flood rim. A parallel stack would be built a couple feet to the right that would drain the second floor fixtures, and would vent this floor's fixtures tying back in 42" above flood rim. The new stack would tie into the old stack in the basement, below the first floor but above the cleanout.

If there is a better way to do it without busting out the basement floor and removing the furnace and A/C to do so, I'm all ears. I want to do the least complex version of "right" that will fit in the space.

 

[Reach4]

What I intended to portray is that the existing stack would remain essentially as-is, with fixture vents added to this stack above this floor's flood rim.

There is a not-colored vent line shown at the left edge of the lower-story toilet tank. That remains? So you intend to have 3 vent pipes and one drain at the altitude of the top of the lower-story toilet tank? Seems unlikely.

And you intend to have 4 vent pipes at the altitude of the top of the upper-story toilet tank? Seems even more unlikely.

 

[VikkiP]

right now, it's a single bath on a single stack with no fixture vents. The closet bend has "taps", one of which is used to drain the bathtub. The sink is teed in about 18" above the closet bend. Again, no vent. I won't touch anything if we don't build the addition, but I need to submit a drawing to the city to get approval for the project itself. I'm obviously not a plumber and won't hire one until we have approval to do the addition in the first place. The full sketch just needs to be able to get a thumbs up from the plumbing inspector, building inspector, and electrical inspector before we can get approval to move ahead. If I can get help understanding what the "right" way could look like, the plumber will submit an actual plan with the permit.

 

[Reach4]

right now, it's a single bath on a single stack with no fixture vents.

The stack is a vent until drainage is added. So if you add a second-story bathroom, that stack will no longer be a vent for the first story.

The closet bend has "taps", one of which is used to drain the bathtub.

It works fine now, but if you take it out, you cannot use that configuration for new work.

The sink is teed in about 18" above the closet bend.

In the stuff you change, cause the toilet to join the other drainage below other stuff. If you can do that, the toilet is probably vented fine. I am not a plumber. I was encouraging you to make your drawings less ambiguous. What you drew looked pretty good, but I was thinking that you either would end up with more vents than you need (which is OK), or the drawing was showing something else.

Also, that now that I know what that orange on the lower toilet represents, not so good for the new.

 

[VikkiP]

Not sure if this is better or worse...

The first floor wet wall is 2x6 construction. I can't change that. Upstairs, since it will be new space, I can make the wet wall as thick as need be to accommodate the venting crossing the old stack.

 

[Reach4]

Much more clear. I doubt anybody will find it not acceptable... presuming you use the right fittings pointed the right way.

You could probably remove the proposed second floor shower vent. Search out the term "bathroom group" for discussions of when you could cut down on vents. But more vents than required should be quite acceptable.

You could probably leave the first floor plumbing the same unless you are moving pipes there too.

 

[VikkiP]

Not moving pipes in the first floor, but the 70 year old galv pipe lav drain is already suspect and has no cleanout, and the previous slumlord patched in radiator hose to drain the tub so as soon as I go to get SOMETHING fixed, getting the rest updated just makes sense and will switch most of the stack to PVC, and avoiding floor demo.

 

[Reach4]

Good thinking. http://www.co.lincoln.or.us/sites/d..._-_helpful_hints_residential_construction.pdf has some good info.

 

[VikkiP]

This is a great site, thanks for the visual reference. "Lavatory wet vent drain on toilet vent. A maximum of a 3 foot 6 inch trap arm" so if my lav drain is only 2 feet from the stack (first floor, drains toilet, tub and lav) and tub drain is also < 3 foot 6 inches from the same stack, then I don't have to add fixture vents? I like that, of course, just don't want to get dinged for the "document review" fee again if I make a mistake.