New home with rough in

[fragment]

I bought a new home two years ago. The builder was going to finish the basement, and the house was already framed and roughed in with the concrete poured. Given that he was planning on finishing the basement, but I asked him not to; I assume the rough in is correct for the basement bathroom.

Here's my question, I want to finish the basement, including the bathroom, but I'm not 100% sure about a couple of things. I'll hire a plumber if I have to, but I prefer to DIY whenever I can (I like the chance to learn something new).



I plan on putting a shower in at the back, then the toilet, then a sink. Not shown is a 2" vent line coming from the ceiling, roughly above the sink location.

I plan on connecting the sink and the shower to the vent line and call it good. I'll need to put a trap under the sink of course, and there is a P trap under the gravel where the shower is to be.

Other then not being certain of what's under the concrete (going on faith that the builder did it correctly), does anyone see any show stoppers?

Steve

[mtcummins]

Just a note before I forget, you should keep that sink line capped, you're letting sewer gasses into your home.

We can't tell from the picture where the main stack is, which has to be functioning as the toilet vent in this setup. If its too far away from the toilet, or if the sink/lav drains tie into it wrong underground, you could have issues. There's not really any way to know that though.

Make sure there's no trap under the concrete on that sink drain. It would be stupid, but you'll find things like that sometimes. dump a bunch of water in there, then look down it with a flashlight. if you see water, there's either a trap, or a clogged pipe down there. If no water, you should be good to go, and install your standard lav P-trap off the riser to the vent, and tie the shower vent over to the lav vent at least 42" above the floor.

[fragment]

Just a note before I forget, you should keep that sink line capped, you're letting sewer gasses into your home.

We can't tell from the picture where the main stack is, which has to be functioning as the toilet vent in this setup. If its too far away from the toilet, or if the sink/lav drains tie into it wrong underground, you could have issues. There's not really any way to know that though.

Make sure there's no trap under the concrete on that sink drain. It would be stupid, but you'll find things like that sometimes. dump a bunch of water in there, then look down it with a flashlight. if you see water, there's either a trap, or a clogged pipe down there. If no water, you should be good to go, and install your standard lav P-trap off the riser to the vent, and tie the shower vent over to the lav vent at least 42" above the floor.

Thanks for the feedback. When I pour water down the sink, it all goes away so no under floor trap there. The main stack is just behind the wall to the right. I'd say five feet away. The shower drain pipe points toward the toilet drain. Seems like I should be good to go.

[mikeplummer]

this is a standard set up....the toilet and the shower are wet vented via lav drain.

[fragment]

this is a standard set up....the toilet and the shower are wet vented via lav drain.

Does that mean I don't need a dry vent to the shower drain? Sorry, just trying to be explicit.

[mtcummins]

Regardless of whether you need to or not, just do it. You can run into a situation where the toilet flushing can suck out the trap of the tub and let sewer gases in. It shouldn't be that difficult to get a vent on there, so why not?

[mikeplummer]

it depends if it was piped properly below the concrete...without knowing it would be safest to back vent the tub if you can