Two bathrooms, one waste stack

[d_san]

I am adding a bathroom directing above an existing bathroom. I am trying to determine the size of my waste pipe. Given that I vent all fixtures properly, is a 3" PVC pipe large enough for two baths?

I have calculated the DFUs for two toilets (3 DFU each), two sinks (2 DFU each), one bath tub (3 DFU) and one shower (2 DFU). This equals 15 DFU.
I have a kitchen sink and diswasher that run into the same waste pipe for another 4 DFU.

A vertical three inch pipe can handle 48 DFU. This is well above the 19 DFU that I need.

Let me know if I'm thinking correctly on this.

Thanks,

[phishfood]

A 3" pipe will be adequate to service that load.

With the code that I work under, a residential bathroom consisting of a toilet, lavatory, and shower/tub is allowed to be calculated at 5 fisture units. But either way, you will be okay with the 3" pipe.

[Reedwalker]

Your fine. 3" is the proper size pipe for your stack.

It may be counter intuitive but in most cases the new upper bath needs to be tied into the stack below the existing bath. Unless you have a relief vent on the existing bath. Which I'm sure you do not.

Sounds like you've done your homework though. Please feel free to ask ad take some before, during and after photos. DIY porn is popular around here!

[Mr_David]

Originally Posted by Reedwalker

DIY porn is popular around here!

The single posters are even more popular