I am doing something similar, but I don't have the ability to draw it out like you did. Today we had a plumber out to help us out with the next step. He said that the toilet needs to be the first in line from the main drain connection. You've mentioned something similar, does the toilet need to be downstream of the sink/shower. Seems like that is the same question asked a different way.
I'm stuck here with the responses, and not sure how to move forward based on the way everything is already installed in the floor, but now have contradicting responses.

The next thing I was planning was laying in the concrete, but since hearing this today, I'm having second thoughts...

 

I moved your post to its own thread so you can get some more visibility.

(Original post: Check My Work! - Basement Plumbing Mock-Up)

 

To respond directly to your post, what is your question? The layout looks good for me. What did the plumber suggest you change? The shower should drain "upwards" into the toilet pipe?

I don't see any issue with your current layout. Everything is vented - assuming you'll have a vent up from the vanity.

 

Thanks for moving it, I was considering the same. He said it needs to have check valve at the inlet of the this "tree" of items. The first item connecting to the main line should be the toilet due to possibly pressurizing the sink and shower drains.
I do plan to vent the sink, and also I will put a vent in the shower drain too, up into the wall of the enclosure just to be sure.

 

You've got me there. I've never heard of a check valve being used anywhere in a drainage system other than just before the main drain leaves the house (backwater valve).

Doesn't mean it isn't needed or required, but I've never heard of one. Maybe it's a local requirement?


Where does the vertical stack go? Are there items draining into that? Maybe that's the issue - that you're basically setting up a wet vent.

 

After talking with this guy the other day, I got a few other opinions on the check valve and everyone agrees with what you said, should be on the entrance to the house to stop any backflow if the outside sewer fills up.

The vertical stack is for the crapper above, which is also a vented and goes through the roof of the house I believe. That stack actually is the original piping and runs down to the floor and then along the length of the house to the main outlet to the street. We tapped into that main drain for this bathroom.

Overall I don't really see any issue, but then again I am no plumber and have never done anything like this. I just use logic thinking and common sense, but that doesn't mean it is right. Everything goes downhill sloped toward the main drain line, and is also wye'd in to keep the deuces moving outside.

 

Where I work, a backwater valve is required for plumbing that's below the nearest sewer lid in the street. That is, you don't need one in most cases, but when you put a bathroom in the basement you might need one, depending. If the sewer if overwhelmed (which can happen) you'll flood fixture below the lid.

And, fwiw, backwater valves are a pain. They clog with toilet paper and aren't much fun to clean.

 

Ok, so the guy showed and and did a portion of the piping he said he had to change, and then covered with concrete somewhat of how we wanted it done.

Obviously its not complete and he didn't show up today to finish it, but I did watch how they mixed the concrete and poured it in to fill the flooring where it was broke out.

Now I need to fill in the area with roughly another 1.5" or so regular concrete mix like they used to fill the hole. After that I would use the self leveling concrete that they were talking about.

I guess what I am after is, what is a good kind of self leveling concrete for using in a basement floor? They were talking about how awesome this stuff called "Floorstone" is, but when I search it out, I don't find too much. I did find the company and will call them to see what they say/recommend. Curious what else anyone here may use.

 

I guess it is now covered in concrete so all code problems have now gone away. Excellent!

In the most recently adopted version of the UPC code they want the toilet to be the lowest fixture attached to a group of wet vented fixtures. In your photos the toilet was the furthest upstream fixture. The idea being that the poo is less likely to leave residue on the other fixture branches or that a big slug of water can create a vacuum that can pull the water out of the adjacent fixture traps, making things stinky. Also in your example the pipe upstream of the toilet wasn't a dedicated vent, it was the waste pipe from the upstairs fixtures. If you get big slugs of water traveling down from above it may also create a vacuum that can draw the water out of the basement fixture traps. Horizontal wet venting also prohibits clothes washers in that group. You appear to have a laundry dumping into the mix down there by the shower. That is a no no. I would worry about suds relief. With no individual vents to 'absorb' the atmospheric change you may get foamy suds coming out of your shower drain on wash day. I don't see an easy corrective fix besides individually venting the toilet, shower and sink, which I would have done by connecting them underground, then have the piping crawl up the outside walls of the bathroom then tie back together in the ceiling somewhere.
I agree with the previous posts about the basement backwater valve. They want to protect the houses with fixtures below the street manhole lids in the event of a city sewer main back up. I have seen homes and businesses with several feet of effluent in their basement from this happening. They want to separate the below grade and above grade piping so only the low fixtures go through the back water gate. Less frequent use means the gate is less likely to foul up with junk. We tie the upstairs and basement drains together just downstream of the backwater valve. The backwater valve also must be in an accessible location.

 

Just get some concrete mix and follow the instructions. Backfill with mostly dirt, then 2-3" of concrete.

Floor leveling cement can be used depending on the flooring you have planned. It comes in bags and is mixed similarly to cement. Again, just follow the instructions and pour it. It will be more liquid-ey and will self-level. You can then use a float to smooth it where it meets the rest of the floor.