Help design laundry drain stack

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Jjherm1

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Hey all,

Redoing my laundry stack, fixing all of the previous owners mistakes.

House was built in 1959 with a cast iron p trap buried under the concrete. It’s eroded, leaked, clogged, and causes the washer to overflow.

Plan is to cut out the old p trap, use a fernco to a long turn 90 to get vertical. From there use a sanitary tee to go back horizontal, using the top of the tee as clean out access. That will go back to a 45 like there is now to get parallel with the wall.

See any major issues or changes for the better in the way the rest of the drain/stack is put together now? Suggestions?

Thanks!
IMG_4467.pngIMG_4466.png
 

zannej

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I'm not a plumber but I've been getting advice from the plumbers on this site and the sister forum http://plumbingforums.com (specifically for advice on washing machine plumbing).
If you don't get any answers here, you might want to try there. Frodo or one of the others might be able to cite code on things.
Just eyeballing it, I'm wondering if the trap arm is a full 4" long. Is that a cleanout on the horizontal run behind the wye?
I've been told that it's not a good idea to use an AAV/cheater valve/studor vent on a washing machine vent because the force of the air being pulled in from a large volume of water going down can rupture the diaphragm in the device, but I think it might be allowed-- you'll just have to check it from time to time to make sure it doesn't need to be replaced. Usually the cleanout is on the vertical vent below where you have the AAV.
 

Jjherm1

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Zannej, thanks for the reply. Maybe I’ll try the other forum if i don’t see much today.

What you’re seeing is a combination of really bad homeowner ideas and some of my temporary fixes. The vent and above grade p trap was me.

The previous owners had a fernco solid from the washer drain to the standpipe. What you’re seeing as a clean out is a back flow preventer. Which they needed, due to the washer now pressurizing the line and back flowing the sink (since the below grade p trap is clogged and runs slow).

The arm is the minimum required, but just.

The AAV was me. I hadn’t heard about any issues with laundry, but that makes sense. They’re not code compliant where i live, but short of a major overhaul, its the best option.

I plan to put my clean out right on the vertical that comes out of the concrete. That’ll go to a long turn 90, then into the old cast iron. That way i have the shortest, simplest access to the cast iron for snaking in the future.

Kinda like this. The sanitary tee replacing the 90 there now. Then the long turn 90 attaches below it to the cast.
IMG_4471.jpg
 

zannej

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Looks like what you've done is an improvement.
 
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AAV needs to be above the top of the stand pipe. I am not sure what code your on but the AAV needs to go up for sure
 

Jeff Handy

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Is that ball valve on the discharge hose because the discharge was coming out too fast, and overloading the standpipe?

Just wondering, since that is a common complaint I see on here and other forums.
 

billshack

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I would make the pipe from the p-trap to the laundry machine connection 30 inches if the drain is not taking all of the discharge from the machine.
 
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