Basement Rough-In Questions

[PJ3400]

Hi all...the 2021 basement finish project has begun. I am trying to figure out the basement plumbing. The foundation was poured in 2015 and as part of that the basement bathroom was roughed in. Fortunately I found some pictures of the drain pipes that I took before the slab was poured.

I’ve attached a very rough drawing of the rough in. The plan was for a wet bar sink on the left, and then a bathroom with a shower, toilet and sink on the right. They recessed the shower floor for a curbless shower.

At the far upper right is a drain stack for two bathrooms upstairs. This is a 4 inch pipe. The stack vents straight up out the roof through a 3-4 inch pipe.

The shower, toilet and sink are all within 4-5 feet of the drain stack as the crow flies, but not in terms of actual pipe length, as they drain downstream of the drain stack, towards the main.

I have two primary questions. One, is there any way this is wet vented? It looks like some of the pipes are 3-4 inches, and some 2. If not, should it have been vented as part of the rough in, and how would I vent it now?

Two, there are only 13 inches from the center of the toilet drain to the sink drain. Given the 15 inch clearance requirement on either side of a toilet from the center, how can this be made to work?

We have since learned that our contractor and his subs, including the plumber, were total hacks, so it wouldn’t surprise me if this is all screwed up. But I thought I would ask, can this be made to work?

I’ve attached pics of the pipes underneath and above the slab, as well as my own very rough drawing. I would appreciate any comments.

Thanks!

 

[WorthFlorida]

Unless you want to break concrete, I came up 2 approaches. Not sure of the foot print you want or the room you have to work with.

1) Just elbow the 2" pipe away from the from the toilet drain and run is through the studs.

2) Make two rooms. Toilet and shower behind a wall with a door, put the vanity on the outside of it and wall it off as another room with a entrance door for the bathroom and one for the toilet/shower room.

Click on image to enlarge

 

[Sponsor]

 

[PJ3400]

Unless you want to break concrete, I came up 2 approaches. Not sure of the foot print you want or the room you have to work with.

1) Just elbow the 2" pipe away from the from the toilet drain and run is through the studs.

2) Make two rooms. Toilet and shower behind a wall with a door, put the vanity on the outside of it and wall it off as another room with a entrance door for the bathroom and one for the toilet/shower room.

Click on image to enlarge
View attachment 69703 View attachment 69704

Thank you! Seems simple enough and I am definitely trying to avoid breaking concrete. I was hoping to leave the shower open and enclosing that pipe would require some framing around the shower (a wall enclosing the pipe would run right into the shower pan), but I suppose that’s not a big deal and we just have to play the hand that was dealt.

Any thoughts on the venting question? That’s a part of plumbing I don’t understand too well. It wouldn’t be too much trouble to run dry vents up into the wall above and connect them to the existing vent....it would just require cutting out some drywall. Was hoping to avoid that if possible. I thought maybe the plumber who installed it might have accounted for venting, but I’d probably spend more time trying to figure it out than just running dry vents.

Thanks again for taking the time to respond.

 

[Jeff H Young]

13 inch should work about 11 1/2 " from finish wall. I guess you need to express where you want the layout? where walls and doors . Or is that your question you want to know what the layout of floor plan will be?

 

[WorthFlorida]

I was just about to ask the same question that Jeff asked. If you're going with a prefab shower pan and it cannot be moved, build the wall for it but as you get past the shower, bump the wall in or out an inch or two to get 12."5" from the floor plate to the center of the toilet drain. With drywall 12".
As far as venting, I'm not an expert in that area, but for the bar sink, definitely use an AAV. The sink looks like it goes right to the main stack, the toilet may be OK. The shower looks too far from the event. Since the floor for the shower is not dirt you can add a vent there. Hopefully someone can answer your venting concern. The 4" pipe going up the wall, is that a drain from above or just a vent? If it is a drain then it's a wet vent and may not be permitted.

 

[PJ3400]

I was just about to ask the same question that Jeff asked. If you're going with a prefab shower pan and it cannot be moved, build the wall for it but as you get past the shower, bump the wall in or out an inch or two to get 12."5" from the floor plate to the center of the toilet drain. With drywall 12".
As far as venting, I'm not an expert in that area, but for the bar sink, definitely use an AAV. The sink looks like it goes right to the main stack, the toilet may be OK. The shower looks too far from the event. Since the floor for the shower is not dirt you can add a vent there. Hopefully someone can answer your venting concern. The 4" pipe going up the wall, is that a drain from above or just a vent? If it is a drain then it's a wet vent and may not be permitted.

Thanks guys. I’d thought about just putting that sink pipe inside a sink cabinet if I had enough clearance from the toilet and didn’t have to do any venting. But that would leave only 12.5 inches or so of side clearance for the toilet. Seems like not enough when the code requires 15. Seems better to enclose the pipe in framing though I might have to do a slight bump in or out on the shower as you say. Shouldn’t be a big deal.

The 4 inch pipe along the wall is the soil stack...it cannot be used for wet venting? The vent that goes up through the roof is almost directly above the toilet pipe...seems like it would be pretty easy to run a pipe up from the sink pipe and connect to the existing dry vent in the wall above. With a dry vent on that sink, could the rest of the bathroom wet vent off of that?

The shower pan is recessed into the slab for a curbless shower...I was thinking about an open bathroom with no wall separating the shower from the rest of the room. Bad idea?

Thanks again.