Check my drain layout for two bathrooms that are being remodeled

[Pbalmos]

Doing your major remodel in Florida slab on grade can you guys check my drain layout and see if you see any problems? Top bathroom has the toilet at the end of the line and does not require venting in my area. I am concerned that it may suck the water out of the shower trap if the 2
' wet vent is not enough. Also in the lower bathroom is the length of the wet vented shower drain going to be a issue or should i just dry vent it.
Thanks in advance.

 

[wwhitney]

On the lower shower, are you going to use a 3" trap? How many showerheads/total gpm? A 2" trap and fixture drain is much more common, although I believe using 3" is allowed. With a 2" trap and fixture drain, you have up to 2" of fall to your vent (the wye with the lav drain), which allows up to 8' of horizontal run. If the run shown is over 8', a more conventional approach would be to reroute the lav drain to connect within 8' of the shower trap.

I would recommend that everything under the slab be 2" minimum size, although some of the drains would be compliant at 1-1/2" (any drain carrying only a lav ; the tub trap arm; and even the shower trap arms if they are under 6' in length). The vents on the lavs can be 1-1/2" if their respective WC drains are 3". [I can't remember if the IPC requires a vent to be a minimum of 1/2 the minimum required drain size, or half the minimum installed rain size; if the latter, then obviously they need to be 2" if you use 4" WC fixture drains.]

BTW, the upper WC is wet vented by the upper lav, which is also wet venting the shower and tub. The IPC has no limit on how far the WC fixture drain can run before being vented.

Cheers, Wayne

 

[Sponsor]

 

[Pbalmos]

Yes the lower shower i was going to branch off the wye with 4" then drop down to three with a 3" trap this shower will have two shower heads. I figured i would never have to worry about it getting clogged. Total distance from this trap to the wye is approximately 10'. Everything under slab is 2" or larger and both vents are 2".

 

[Pbalmos]

Progress today. Anyone see any problems? I decided to dry vent the shower since the trap arm ended up being 9' long. After i get outside what is the maximum slope for the 4" line to where it connects to the septic tank? I think i have around 28' and 18" of fall which is way over 1/2" per foot. Should i just run 1/4" per foot and then 45 down to the tank? I'll post pictures tomorrow.