Triple Stacked bathrooms. Am I close to understanding this....

[Paul C]

Two story with basement built in 50's with 4" cast iron main and vent. I want replace everything during the 1st and 2nd floor bathroom remodels and later lower the floor in the root cellar and stub for a bathroom/laundry room.
(Right now the main leaves at only 24" below ground level (and first floor joists) and connects to a clay tile lateral. I just want to make sure I've accounted for the venting if I do end up finishing the basement and replacing the sewer main)


Black = 2"
Green = 3"
Blue = 4"
Red = 3" Branch lines from other parts of the house with their own vent stacks.

The design looks compliant to me based on my learning... or am i missing something or doing something stupid?

Thanks,

Paul

 

[Terry]

You're doing it right.
So nice to see a drawing like that.

You can have four toilets on a 3" vertical.
On the horizontal, you need 4" when the forth one comes in.

 

[Sponsor]

 

[Standardairconditioner]

I understand vent loops are easier, but are your not able to get any graded wet vents in there?

 

[Paul C]

You're doing it right.
So nice to see a drawing like that.

You can have four toilets on a 3" vertical.
On the horizontal, you need 4" when the forth one comes in.

Thanks, I've been studying this for two days and a couple trips to HDepot and Ferguson's to boot. Thought i may have overdone the venting but I guess if everything in the house is flushed or draining at the same time I'll be safe.

 

[Paul C]

I understand vent loops are easier, but are your not able to get any graded wet vents in there?

Just got a handle on dry vents.... wet vents are still confusing me as to when and where to use them... feel free to mark up my drawing with your ideas.

Both first and second floors have 6" wet walls to work in.

 

[Standardairconditioner]

Photos of each actual room will help.

Vent loops can be used when there is insufficient horizontal room for graded wet venting, that can result from an intended renovation not working with an existing structure. There is plenty of wet vent talk here in the forums here.

Your diagram has an excessive amount of vent loops, which not only requires more material, but you are setting yourself up for troubleshooting issues 10-20-30 years down the road. I'd hate to look for the dead squirrel that can be lodged anywhere in your maze.

Less material means less to break down. No one really knows the lifespan on the abs/pvc/glue, we don't know if 50-60 years later if pieces will just fall loose apart from gravity. Commercial construction will still use cast iron, mostly for fire safety reasons, but when well maintained, can last overy 75 years. So if glue can deteriorate and break down, let's keep it to a minimal.

 

[hj]

Your second and third floor showers can connect beneath the toilets. They do not have to connect to the main riser.

 

[Paul C]

I wont have actual photos for a few weeks... hopefully. Until then this Sketchup drawing will have to do. Both bathrooms are 5x8. About the only things I cannot change are the 2x6 floor joists for the second floor. With 3/4" sheathing + underlayment + tile, I barely have enough room for the 1-1/2" trap for the tub and the 4x3 90 for the toilet (3" flange fits inside the 4"). I know on the first drawing I listed a shower on the second floor but it is a tub. Under the first floor is open but those joists are only 2x8.

So, in looking up wet venting, I could wet vent the second floor sink to the stack. The tub I cannot as there is not enough room unless I drop below the joists to make the horizontal run to the stack... but wouldn't that be in essence an "S" trap?
As far as the first floor sink.. I was under the impression that once you use the stack as a drain, it cannot be used as a vent. If that is true, I cannot wet vent the first floor sink to the stack (or anything else on the first floor to the stack).

I'll run it by the building department inspector this Thursday and see what they think about the wet venting possibility in this scenario...

I'll let ya know what changes we come up with if any.

 

[hj]

quote; I could wet vent the second floor sink to the stack.

I think you have a wrong concept of "wet venting". NONE of your fixtures are appropriate for a wet vent, and there would be no reason to revise anything to make one. Wet venting is merely a "fall back" option when things are aligned so that a single vent serves a dual purpose.

 

[Paul C]

Agreed, I was just entertaining the possibility based on some earlier feedback.

Thanks (great forum by the way)

 

[Cacher_Chick]

The plumbing codes used in the U.S. have some major differences compared to that of Canada. Everyone must remember that when reading posts from across the border.