Re-plumbing a 170 year old house...

[nfc911]

We recently bought a home in Charles Town, WV. I'm working on redoing the plumbing currently as the supply lines are all galvanized, closed shut and/or leaking. While the plaster walls/ceilings are open I want to replace the galvanized drain lines and possibly cast iron drain lines. I've sketched out the layout of pipes that I can see (and guessed at the ones that I can't see yet).



There is one full bath on the 3rd floor that drains via a stack straight to the basement where it picks up the two half baths from the 1st floor and basement before tying into the "main" stack. There are two full baths on the 2nd floor, a kitchen and laundry that tie into the "main" stack. The black lines denote Cast Iron pipe (4" for the most part) and the grey lines denote galvanized (mostly 2", some 1 1/4" maybe others).

My main question: is the existing layout ok? Is venting ok? Is there anything that was done over the past 100 years ago that I should be looking for and replacing if found?

Thanks for any and all insight.

West Virginia uses the IPC Plumbing Code

[Terry]

The drawing is missing much of the venting.
You can use the vent of a lav to wet vent a tub or shower, assuming the pipe sizing is 2" or larger.
If you're not wet venting, then you would need to vent the lavs, showers, tubs, kitchen sinks, laundry trays before they enter the main stack or branch. Venting is what prevents a trap from siphoning.

The first rule of plumbing, is that for every pipe going down, there is one going up through the roof.

2nd rule is that the pipe through the roof (the vent) is plumbed between the trap (p-trap) and the common line.

[hj]

Forget about how it WAS done and concentrate on how it HAS TO BE done, because that is all that matters. Your drawing is missing a lot of vent piping, but we do not know if it is because it is not there or you just cannot see it.

[nfc911]

Terry,
Your drawing is what I understand to be 'normal' non-wet venting, is that right? What would be the difference for it to be a wet vent?

[nfc911]

hj, I plan to make it is as 'right' as the inspector requires. I'm working under the assumption that what is in the drawing is pretty much what is there. I've got 3 vent pipes in the attic with nothing tying into them horizontally. The exterior walls in the house are brick so aren't hiding any pipes but there is a chance that the interior paritions that were added when indoor plumbing was added could be. I just haven't gotten up the guts to start cutting into the 170+ year old plaster ceilings below the bathrooms or the 100+ year old floors in the bathrooms to find any pieces I may be missing.

[Terry]

Wet venting is for the "same" bathroom group, on the "same" floor.
Here you see lav over toilet and tub over toilet.
You can also have lav over tub or shower.

Kitchen sinks, laundry trays and washing machines don't get wet vented.

[DavidTu]

I understand the wet vent is to code; but also that code specifies the minimum functional requirement, not necessarily the BEST. It seems wet venting would be inferior to normal venting... is it? Ignoring cost and materials, would normal venting always be a superior functional solution? Or is this not so?

Thanks.

[nfc911]

So... I really don't have anything even close to proper venting. The only thing in my original drawing that is vented is the tub and toilet on the right of the 2nd floor and the lav on the 3rd floor? Everything else is lacking any kind of proper venting?

[Terry]

3rd floor bath
With IPC, it looks like the lav is wet venting the tub and the toilet.

There is no requirement to vent the toilet with IPC, they consider the refill on the tank to be enough to replenish the bowl, they expect to the bowl to siphon and then get refilled.

[DIYPlumber90]

The drawing is missing much of the venting.
You can use the vent of a lav to wet vent a tub or shower, assuming the pipe sizing is 2" or larger.
If you're not wet venting, then you would need to vent the lavs, showers, tubs, kitchen sinks, laundry trays before they enter the main stack or branch. Venting is what prevents a trap from siphoning.

The first rule of plumbing, is that for every pipe going down, there is one going up through the roof.

2nd rule is that the pipe through the roof (the vent) is plumbed between the trap (p-trap) and the common line.

Thanks for the visual aid there Terry. Great job by the way.