Basement bathroom rough in

**pmfleisch** · 02-23-2013, 09:38 AM

Hello,

I'm a DIY'er wanting to start a basement bathroom project. I'm going to hire a plumber for permitting and final ok's, but want to start trenching to get the project going.

The bathroom will have a shower, lav and toilet. I also want to put in a new floor drain on the other side of the bathroom wall to replace the current floor drain that will be removed by my project.

There is a floor drain that I'm going to drain everything into (under grade). There are dry vents above the bathroom that I'm going to vent everything into.

Here's my questions...

1) Does my layout make sense? I think I'm doing it right, but the floor drain tied into the shower is a bit of a guess.

2) If the layout does work, do my sizes look ok?

3) How deep do all these things have to be? Is it just enough to keep a 1/4" per foot angle for drainage or is there a 6" under flood requirement?

4) Any other bits of wisdom would be appreciated.

Again, I'm not planning on doing this start to finish by myself, but I want to get things going. I've got a baby on the way and want to do what I can before I run out of time.

Thanks for your help.
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**jadnashua** · 02-23-2013, 11:26 AM

As drawn, neither the new floor vent nor the shower are vented. Depending on the depth of the existing line you are tapping into, this could be easy or very difficult and may require a pump and basin. If you can maintain 1/4" per foot from the drains, you should be able to do this..the slope does not need to be higher, but can be. It should not be lower than that slope and cannot contain any flat or uphill sections.

**pmfleisch** · 02-23-2013, 11:43 AM

I changed it in the original post. I thought I'd be ok to vent the shower with the lav. I think this should correct the shower and floor drain, right?

**Gary Swart** · 02-23-2013, 11:45 AM

I can understand you desire to get a head start on this job and get as much done yourself as possible before the plumber, BUT (seems like there's always a BUT) You are very likely to create more work for the plumber if you just go ahead on your own. It might be wise to have the plumber show you what you can DIY and what would be best left for him to do. What you have sketched will not work.

**jadnashua** · 02-23-2013, 01:09 PM

I don't know the cost, but Terry mentions he usually hires a concrete cutting company...nice clean, straight cuts, no dust. Probably cheaper than paying the plumber to do it. The real key to how well this may all work is how deep the existing drain line is. And, are you sure that floor drain drains into the sewer and not to a drywell somewhere? A floor drain usually requires a trap primer...if one isn't provided, it eventually dries out and becomes a direct opening to the sewer. If you look down the floor drain, you should see some standing water in the trap. If it isn't trapped, it probably isn't going to the sewer, but to a drywell or who knows where.

**cacher_chick** · 02-23-2013, 02:39 PM

Your idea of plumbing is incorrect, as every fixture must have a trap, and every trap must have a vent. Vents cannot be run under the floor, they must be vertical.

Your plumber is going to do it however he wants to do it, and it will be better than what someone who has no experience will come up with.

**pmfleisch** · 02-23-2013, 02:57 PM

Thanks for writing back. What this is all about is I want to start working...while I've got the energy and time. I'm not as worried about specifics like sanitary tee vs. wye as much as where I would be trenching - which I'm planning on doing myself. Most advice I'm getting says I should get a plumber first, so I'm guessing I'll have to do that. I was hoping to learn enough from forums to A - develop my understanding and B - get started.

As far as the existing drain goes though, I can indeed see water in it and it does go to sewer. The cleanout is a five feet away from the existing floor drain that I want to tie into.

hj · 02-23-2013, 03:04 PM

DO NOTHING until you have hired the plumber and HE tells you WHERE to cut the floor. There is NO WAY we could advise you about how HE would want to install the piping. However, I can guarantee you that it will NOT look anything like what you have drawn.

**pmfleisch** · 02-23-2013, 03:07 PM

removed message

**pmfleisch** · 02-23-2013, 03:10 PM

Ok, I get it. I'll wait to talk to the plumber. I guess I just thought there was a right way to do this and those with wisdom could share that wisdom. I'm thankful that you're not being mean about it, some responses I've seen to people are ridiculous. That said, I was hoping to learn something and all I've learned is that I'm not doing it right. I knew that before I first posted.

**mtcummins** · 02-23-2013, 03:12 PM

As others have stated here, you want to hire a plumber first, then figure some of this stuff out. Get a plumber to come and give you a bid. While he's there, tell him that you'd like to do the digging, and have a can of line spray paint on hand for him. Ask him to mark where he wants cut out, and about how deep he wants it dug out.

There really isn't any way for us to help you beyond that. Doing this part of the work will save you a lot of money, the rest is up to your plumber.

**Gary Swart** · 02-23-2013, 05:19 PM

mtcummins and HJ really state what I was trying to get across in my answer, they just did it better. Get the lines for the trenching marked, hire a concrete cutting company to cut the concrete, dig out the soil necessary, then get out of the way. Having broken out concrete in my basement once, I strongly suggest you hire the concrete cut. They do it dust free as well and nice straight line cuts. You can not believe how much dust breaking concrete with a rotor hammer can raise! Trust me, you don't need that kind of mess to clean up.

**cacher_chick** · 02-23-2013, 05:34 PM

If 6 different plumbers did the same job, it would be very likely they would each do the drain and vent piping differently. This is why we can't tell you where to dig.

**pmfleisch** · 02-23-2013, 05:54 PM

Ok, thanks everyone. I'll take your advice. I guess the biggest thing I learned is how much design is left up to the plumber. I really just assumed that in order to follow code, it would have to be just one way. When it's all done, I hope I'll know more about it and then you can tell me what I was doing wrong. Thanks for taking the time to write. I hope you appreciate that I know enough about what I don't know to take the time to ask and in this case turn it over to the pros.