Laundry drain backing up in bathroom sink. Could it be Tee?

[Jetboy55]

I just added a laundry drain to my main level closet. I chose this because it abuts my wet bathroom wall. So in the picture with the tee, you can see that I found a tee to tap into. The existing horizontal branch goes to my bathroom sink. The other horizontal branch had galvanized pipe in it and was run for an additional bathroom sink (double vanity) that was never installed (it was capped). So I removed the galvanized pipe, and tapped into the tee for my new laundry drain. See pictures. I stuck with 1 1/2 because that was the size of the cast iron tee, and it seemed pointless to use 2 inch drain into a 1 1/2 hub. Plus my washer manual says 1 1/2 is sufficient for my washing machine.
The problem arose when we did the first load of laundry. It was a large load. After the load was done, we discovered that the bathroom sink had filled and flooded over onto the bathroom floor. So I figure its either a clog that is common to both fixtures, or maybe, just maybe the force of the washing machine drain is "shooting" water straight across the tee and into the sink. So I tried the following.....
I held the stopper in the sink down and plugged the sink overflow. Then we did a test run of a large load of laundry. It tried to fill the sink, but holding the sink drain closed stopped it. No other fixtures flooded (toilet, bathtub), and neither did the new laundry drain. This leads me to believe that the tee in the picture is not suitable for this situation. If that is the case, I assume I will have to cut out the tee and convert to PVC with a different type of tee at that location so the water doesn't "shoot" across the tee. If so, I will also switch the laundry drain back to 2 inch.
I need advice on this, is "shooting" water across a straight cast iron tee, especially when the water is fast moving like from a washing machine, even a thing? Do you think that is my problem?
Thanks all for your help. Hopefully my pictures will load ok and the text isn't too small.

 

[Reach4]

or maybe, just maybe the force of the washing machine drain is "shooting" water straight across the tee and into the sink.

I suspect that.

I held the stopper in the sink down and plugged the sink overflow. Then we did a test run of a large load of laundry. It tried to fill the sink, but holding the sink drain closed stopped it. No other fixtures flooded (toilet, bathtub), and neither did the new laundry drain. This leads me to believe that the tee in the picture is not suitable for this situation. If that is the case, I assume I will have to cut out the tee and convert to PVC with a different type of tee at that location so the water doesn't "shoot" across the tee. If so, I will also switch the laundry drain back to 2 inch.
I need advice on this, is "shooting" water across a straight cast iron tee, especially when the water is fast moving like from a washing machine, even a thing? Do you think that is my problem?

I think that your test was good.

I don't see an easy cure for this. What I would feel confident with is to inject the standpipe lower. This would involve changing out some cast iron.

 

[Sponsor]

 

[Jeff H Young]

rework the piping properly . and be sure the existing is clear.
youll have a little challenge getting everything to fit.

 

[Jetboy55]

OK, thanks for your advice. I will be replacing this with PVC this weekend. I do see difficulty changing out the cast iron in the bathroom wall because of space concerns. I would like to use a sanitary tee in place of the cast iron tee, but I am concerned the problem will still be there, as a sanitary tee doesn't direct flow much better than what I have, do you guys agree with that? Using a wye with street 90 to go to either drain (washer or bathroom sink) will require more space than what I have, especially to the sink because I can't move that like I can the washer box. Any suggestions would be appreciated. I guess I could just drop the washer stand pipe into the basement, p-trap it there, and just tie it into some new PVC down there. Space is hard to work in because of existing duct work and a beam, but not impossible. I would like to contain this work to the bathroom wall, but maybe I can't. Anyway, as I decide what to do, I could benefit from a few more questions.....
1. The cast iron vent going thru the roof, will the seal fitting in my roof work with PVC if I replace the cast iron, or will I have to replace the roof seal (it was just installed with the new roof a couple of years ago before I bought the house?
2. When I cut the cast iron, do you recommend I rent a cutting tool or just use a recip saw with diamond blade?
3. If I leave the cast iron vent, how do I support it as I remove portions of it below and put in a no-hub connection. I do have easy attic access to the vent.
Thanks again everyone.

 

[Reach4]

3. If I leave the cast iron vent, how do I support it as I remove portions of it below and put in a no-hub connection. I do have easy attic access to the vent.

You can often use a "riser clamp" .

 

[Jetboy55]

Thanks for the advice about the support clamp. However, now I'm not so sure what is going on.
Even though my original tests supported the idea that the problem was the "tee" and not a clog, the system
has changed its behavior in the last day or so. Now, it floods the washer stand pipe whenever we do a load of
laundry if I force the bathroom sink stopper closed. So now I am back to thinking it is a clog. I ordered a 50ft camera to put down
my vent pipe and see what is going on. Will be here Friday, so I will report back and probably ask for more advice.
Thanks to everyone.

 

[Reach4]

Septic or sewer?

Do you have a cleanout below your pictures?

 

[Jeff H Young]

I think you got a clog . and it is probably right there at the san tee . You got open walls though might as well fix it right. or if you want an easy and cheap fix try blasting a jet nozzle on the end of a hose down vent pipe from roof you should have a hose might need a cheap straight nozzle shoots a fine stream with power . work it up and down in area of the tee just don't flood out the house I'd consider this a temp fix and do repair regardless let us know how it works

 

[Jetboy55]

The camera is here. So this afternoon I will take a look at it. Also, I do have a cleanout in the vertical stack in the basement, in the PVC section, just below where I took the picture, but no other cleanout in the vertical sections that serve the bathroom/tub and vent. Also, I am on the city's sewer system.
I will probably go with the easy fix for now, regardless of what I find. I have several projects to get done before winter, I've had this house for 1 month now. The proper fixing can wait until next summer. I just tackled this laundry drain because I promised my wife I would move the laundry to the main level, she is partially disabled.

 

[Jetboy55]

OK, I got the camera down the vent and found my cast iron is shot. It looks like an ancient cave on another planet, with bulbous "rust growths" everywhere that I assume won't "clean out" with a snake and would be bad for my downstream system anyway. So I have decided to replace it all. Thanks for the advice. I'm going to start a new thread for a couple of questions about sani-tees and S-traps. Thanks again.

 

[Jetboy55]

Here's a pic of my cast iron right above the first 1/4 bend below the bathroom/laundry.

 

[Reach4]

Not that good of a view. Bringing in a professional drain cleaning specialist would be worthwhile. Be cautious of those that advertise a lot; they tend to be into bait and switch.

 

[Jetboy55]

Well, the saga is over for now. After finding out that I cant rent or buy a pipe chain cutter anywhere near me, I decided to just replumb the washer drain down into the main stack, below the lav branch drain. It's done and working well. I will tackle my bad CI pipe next summer perhaps. Thanks for all the help and advice.