Bathroom plumbing advice

[João Santos]

Hi everyone,

I'm a home owner, currently building a two floors house and having some discussions with the contractor around bathroom drain pipes.

I live in a country where people are used to have a floor siphon and connect all appliances to that siphon, 95% of houses are built like that. Problem is that... waste just accumulates there, with time it gets smelly, it requires maintenance... etc... I really don't want it.

So, I'm trying to convince the contractor to use a different model, where appliances have their own siphons and connect directly to the main (vertical) drain pipe that goes from the top of the building (for ventilation purposes) to the sewer boxes outside. This pipe is placed in a wall that goes through one end of the bathroom, it's the wall where both basins are installed.

I'm attaching an image of what I'm suggesting the contractor to do.. would appreciate if you had some time to comment and let me know if you believe this is safe or will bring me any type of problems.

 

[Terry]

Here each fixture has it's own p-trap.
Each trap gets a vent which breaks the siphon. A trap holds water to block the sewer gas from entering the home. You don't want that water to siphon completely out of the trap.
Below is a standard layout for two bathrooms on two floors.

A wye fitting will siphon the trap too on the vertical. We use a santee fitting on the vertical.

A vertical pipe to a horizontal we use a wye or a combo.

 

[Sponsor]

 

[João Santos]

Hi Terry,

Thank you for your reply.

In my case each feature will have its own p-trap, no questions asked there.

Problem is really how to connect the drain pipes after each p-trap to the main pipe.
I'm basically connecting the features to the vertical main sewer pipe with a double Wye.

This is what we use in Portugal... you connect all features there, and then a single line to the main sewer pipe. But I don't like it, waste just accumulates there... it needs a cover on the floor of the bathroom, but if for some reason it has some leak, smells will get out of there.

 

[João Santos]

So the question here is really, if the double Wye connecting two features at the same level will bring me any kind of problem.

 

[Terry]

Let me think about that. That is a bit different than what I'm used to seeing. Let's see what others think.

 

[João Santos]

And just to add... here we don't have a vent per feature. We have a main pipe that goes all the way to the roof... that pipe serves two purposes...
- it vents all drain pipes that connect to it
- it takes the water drained by those drain pipes to the lower level

 

[Terry]

And just to add... here we don't have a vent per feature. We have a main pipe that goes all the way to the roof... that pipe serves two purposes...
- it vents all drain pipes that connect to it
- it takes the water drained by those drain pipes to the lower level

Seeing that's it's 4" I can see that might work for venting too.

 

[João Santos]

I believe it is 3". But... it's calculated to support all those features connected to floor siphon... there's no other venting going on there, even if I use the "standard" model we use over here.

 

[João Santos]

And here's a good image of our model, which shows those "boxes" on the floor of each level. What I'm basically doing is shortcutting those boxes and connecting directly to the vertical pipe.

 

[Jeff H Young]

And here's a good image of our model, which shows those "boxes" on the floor of each level. What I'm basically doing is shortcutting those boxes and connecting directly to the vertical pipe.

Mr Santos very interesting but our plumbing codes are very different the plumber might not know how we do things here . So if he doesn't have a plumbing plan might not know how to build it American style , however when we build our plumbing correctly it works perfect.
I don't like the central spider box system either. although the main stack for drain and vent I like as long as it works good