How do I Fix This?

[ericlee20]

Hello. I'm new to posting here but have been using this site for information since I started my home build a year ago. So I have a question with my shower drain setup under slab. I have attached the pic of what I think will work but not sure if this an s trap or not. I want peace of mind and to get others opinions before I glue it and cover it up for years. It goes from this to a 90 below then into the 4" main.

 

[Reach4]

It is an S-trap.

 

[Sponsor]

 

[John Gayewski]

Yes it's an S trap, the trap needs properly vented.

 

[Jeff H Young]

might be able to change the 90 to a santee extend up with vent or aav. your code probebly allows an 1 1/2 line going to a bath tub

 

[ericlee20]

The 2" vent in actually attached to the 4" main running under that double stud wall about 2ft away from it in the wall. See attached picture. I think im limited on what I can do here. Cant put a vent here since its in my shower floor pan area. Any other ideas on correcting this? Maybe extending it to a center drain?

 

[ericlee20]

Anyone have any opinions on fixing it?

 

[John Gayewski]

Replace the 90 with a tee. Then offset the vertical section onto the framing for a vent.

 

[Reach4]

Or use an AAV to do the venting. An AAV must stay accessible, and be at least 4 inches above the output of the trap.

 

[ericlee20]

So the vent in the wall right next to this wont vent this shower?

 

[John Gayewski]

The vent opening (inside of the pipe) needs to be above the trap. Hence why it's an S trap. S Traps siphon, to break the siphon you need a vent between the trap and the drop.

 

[ericlee20]

Could this be resolved by making the trap arm longer? The original plumber has kind of made this a problem to replace and do it correctly because they for whatever reason decided to glue a 90 right next to the 2" exit of the 4" wye under slab. So cutting it off to put my trap down below might be impossible for me at least. So next option is to cut into the 2x4 base and put in another vent?

 

[WorthFlorida]

The trap arm must be a minimum of twice the diameter of the pipe. You may need to do more digging. I would rotate the trap about 90 degrees counter clock wise. That will place the trap to the left of the drain and allow to have 4" needed to not have an S trap at least from the picture. Do some measurements before cutting out pipe.

Venting may work but it appears there would be a lot of concrete to chop out.

 

[ericlee20]

So I got myself a tee. How about this with the 2 90s pictured to get the vent inside the wall and under the shower pan? I can also turn the trap a bit to give myself more trap arm room.

 

[Reach4]

That looks like it will work, if you can vent the top of the sanitary tee with a vertical (within 45 degrees of plumb) pipe. The vent needs to stay vertical until it is above 6 inches higher than the flood level. The flood level would be the rim of the shower base where water could pour over and onto the non-shower floor in case of backup.

If you have a problem with that, you will need to dig out concrete to closer to the sill plate.

If using a purchased shower base, this may be helpful.

 

[ericlee20]

That looks like it will work, if you can vent the top of the sanitary tee with a vertical (within 45 degrees of plumb) pipe. The vent needs to stay vertical until it is above 6 inches higher than the flood level. The flood level would be the rim of the shower base where water could pour over and onto the non-shower floor in case of backup.

If you have a problem with that, you will need to dig out concrete to closer to the sill plate.

If using a purchased shower base, this may be helpful.

So what if I used 45s instead of 90s to get my vent over to that 2x4 plate then run up the inside wall?

 

[Reach4]

Yes. A 45 into the top of the santee, and another 45 to continue upward is considered vertical.

 

[ericlee20]

That looks like it will work, if you can vent the top of the sanitary tee with a vertical (within 45 degrees of plumb) pipe. The vent needs to stay vertical until it is above 6 inches higher than the flood level. The flood level would be the rim of the shower base where water could pour over and onto the non-shower floor in case of backup.

If you have a problem with that, you will need to dig out concrete to closer to the sill plate.

If using a purchased shower base, this may be helpful.

So what if I used 45s instead of 90s to get my vent over to that 2x4 plate then run up the inside wall?

Yes. A 45 into the top of the santee, and another 45 to continue upward is considered vertical.

Sweet we're getting there. I'm planning build custom tile bed for this shower so drain placement it's a big concern. Only want it to drain properly lol. Thank you for the help on this. Now I can get to chipping concrete.

 

[ericlee20]

Alright got her mocked in place minus the length I need to get up wall. The vent is low enough to be under the shower pan once built. What do you think?

 

[John Gayewski]

Looks correct to me.