How to install a cleanout into a vent stack in a exterior block wall

[RubyToeBeans]

I want to install a cleanout in a PVC vent stack in my bathroom. The vent stack is located inside an exterior block wall. I'm looking for specific advice as to the type of cleanout to install (90 vs 45) and how high up the vent stack to meet code and common sense. I'm comfortable with cutting through the outer surface of the cinder block and punching out enough to give me room to work/glue-up/connect the new cleanout. Here's the background on this situation.

In 2006 we did a home renovation and expansion. We added a third bedroom and master bath which has two separate vanity sinks on either side of a corner jacuzzi tub, in addition to a toilet and walk-in shower. There are two vent stacks, one for each vanity sink. The plumbing was professionally installed and passed code inspection, however, for some reason, no one required or asked for a cleanout in either of the two vent stacks or anywhere in the bathroom drainage design. Last Saturday we had a whole-house clog situation that required an expensive weekend clog removal procedure by a local company. Of course, the clog was located at the point where the original plumbing contractor spliced a PVC coupling to flow the new addition's drainage into the original 1964 cast iron drain pipe going to the city sewer. It was identified by an inspection camera and found to be soft material and toilet paper. The cast iron pipe in the original slab and the run out to the city sewer has a lot of rust spalling and is grabbing/holding material.

I'm annoyed they didn't put a damn cleanout to service any clogs in the bathroom and I'd like to add one for future issues. Unfortunately, I can't seem to find any YouTube DIY coverage for my specific situation so I'm hoping the Terry Love collective mind can steer me in the right direction. Thanks in advance.

 

[RubyToeBeans]

Wow. I gotta say, I'm seriously underwhelmed at the forum response to my question. I would have expected at least one response by this point. I guess I'm on my own with this one.

 

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[Sylvan]

A CO should be installed at every change of direction greater than 45 Deg and at the base of the stack and no more than 100 feet apart. Personally I install a CO no more than 2 feet off the finished floor as it is easier to snake the line

A 45 deg access is easier to snake than a 90 deg

How did this pass inspection without the proper CO installed?

 

[RubyToeBeans]

Sylvan! Thank you for your reply. My apologies for my late response.

The work was done by a licensed plumbing subcontractor and inspected by our city permitting office. Our town is known for being pretty strict with their inspections so I'm going to assume the work passed code back in '06.

To your comments: There is a CO installed approximately 25 feet from the new construction bathroom plumbing. Our renovation included an expansion of the kitchen which required new construction in that area as well. I've attached a poor quality photo of the plumbing rough-in prior to the slab pour. Picture #1: The blue circle is the CO the plumbers installed in the kitchen expansion area. The yellow circle is where they tied into the original cast iron drain pipe coming from the house, which is also where we had our recent whole-house drain stoppage. Picture #2: I want to add another CO in the drain stack shown in blue circle, which is the most direct line to that cast iron/PVC connection. Hope this clarifies the situation a little better.

The main question I have is whether I should place the CO below or above the tee connection for the sink installed at that location. Seems like it should be below, but I'm not a plumber! Thanks for your patience.

 

[Sylvan]

I would install it below the tee as it will be easier to snake / water jet the line.

Underground piping I would use 2" minimum

 

[RubyToeBeans]

Thank you for the advice. I'll post the gory details when I finally get it done.