Wet venting question

[ShaunS]

I was advised to post over here from the John Bridge forums. I had a plumber replace and relocate my cast iron shower and toilet drains in my slab foundation. Basically the toilet and shower vent swapped locations +/- 12". When I was posting pictures over on John Bridge, they suggested that perhaps the venting was done incorrectly. So here are a few pictures of the work before the concrete patch and after. I have two concerns in increasing severity, a) is it up to code? and b) is it going to work well or is it going to give me problems.

 

[hj]

Why were the toilet opening and the shower trap put directly underneath where they had to go, instead of using offsets? Especially that offset toilet flange which was a TERRIBLE idea.

 

[Sponsor]

 

[ShaunS]

What do you mean by offsets?

 

[Jadnashua]

Especially when dealing with new construction where there are no obstructions...it's always best to just have the riser run vertical without any offsets, or angled connections. Extra joints, harder to fix a joint, potential leak points, and with a toilet, a potential clog. HJ has been doing plumbing for many decades. Trust him.

 

[ShaunS]

Got it. My main concerns still stand though...is it up to code and will it work well? I need to know if it's worth fighting the plumber to change anything considering the concrete has gone in and cured.

 

[MKS]

Where is the main drain that the toilet and lav/shower drain into? Based on the first picture.
Offsets can be a clog point I believe.

 

[ShaunS]

 

[MKS]

OK so the lav and shower come together run towards the toilet the turn into a y in the toilet line and run to the red arrow?
Have a look at this.

 

[ShaunS]

OK...a little confusing, but it seems that I'm good?

 

[MKS]

I think your situation is similar to the 3/4 sketch.
If this needed to be cleaned with a snake it would be difficult.
A lot of things work if the drains run downhill.
I can not say it would meet code or be good.
If it is similar to the previous installation and it worked you will probably be OK.
Can't hurt to discuss this with the plumber.
I'm sure one of the qualified people here will give you an opinion.

 

[ShaunS]

It is quite different from the previous installation due to the toilet and shower being swapped. Also, there is another bathroom on the opposite side of the wall, so it's some combination of the 3/4 and the back-to-back bathrooms.