I have stack that served only the kitchen sink, dishwasher and one other bar sink. It was exposed in the basement below all of the fixtures. I removed the portion that terminated into a 3" cast iron hub protruding from the cement floor. The portion removed had a branch for a washing machine that has been relocated. The bar sink wasn't vented properly. There is another branch from a planned bathroom addition that needed to be added in.

As soon as I removed all the branches from the ~7ft of stack I noticed movement at the base. I secured the stack and removed the lead caulking. I removed the stack very carefully, because the hub at the floor was moving and I didn't want to cause any damage to the buried joint. It looks like a 90 deg elbow that continues to a floor drain nearby and finally the main.

I have only had the house for over a year. The basement apparently had water penetration issues before because a wall covering/gutter system was installed around the perimeter of the floor. The hub is very close to the wall (abutting) and I can see some hollow behind the buried fitting by looking into the narrow gutter.

Can I test the integrity of the joint and simply back-fill the gap to stop the movement it if it passes? If I need to cut open the floor and fix the joint, what is the best practice for tying in the new PVC stack before burying it again?



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if you do a test on that pipe, how are you going to tell if it is leaking if it is buried in cement?
since you have access to it in the future, i would just cement it so it is solid and not worry about it. if it turns out to be leaking in the future, cut the PVC, bust the cement and replace a section of pipe.
to join PVC to an open soil pipe hub, you will need the appropriate size rubber 'donut', some grease and some muscle.
the donut looks like this..

Thanks for your reply packy. I like your idea of just secure and move-on since I am sort of schedule driven right now.

For testing, I was thinking I could send a test ball plug down far enough that its past the joint (1-2 ft?). I have a donut that I am using for the new stack. I could put up to 7.5 ft of PVC in and fill it with water. Then just wait to see if it holds. Assuming it holds I cut the PCV in place and start fitting up.

Assuming I pull this all out in the end, and to clarify, I can use a donut under my slab?

Thanks

depends on code

but

it IS better than a known leak

just clean the hub really clean (hand sand with a strip of emory) to ensure good 'grab' by the donut

the secret to successful 'cheats' is the care used in fabrication

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

"I removed the stack very carefully, because the hub at the floor was moving and I didn't want to cause any damage"

The fact that it was moving would concern me. Something is broken or disconnected.

I hear you Paul,

I installed the donut and 5 feet of 3" pvc. I couldn't get to a test ball plug, but I had a clog buster that attaches to a hose and inflates into the pipe wall. I was able to get the "plug" 9 feet in, so 4 feet past the hub. I poured water into the pseudo stack but it didn't hold an inch. I deflated and pulled back considering that I may have past the elbow and into a leg of a wye. I tried several times and it never held water. Down to a about 1.5 feet from the hub. I know the clog buster isn't the ideal tool, but I couldn't pull it out once inflated and the rate the water drained tells me it wasn't seeping by the plug.

I'm pulling up the floor around it tomorrow. The way the hub moves makes me believe the disconnect is near. I can tell the direction of the turn, but I'm not sure how far to cut. Any input on the radius of a 3" cast iron 90* elbow?

Also, my city follows IPC with little exception other than permitting annotations. I was reading IPC, but it isn't clear to me what connections between cast iron and PVC are allowed to be buried. Any input on best practice vs whats allowed?

Thanks

I'm a homeowner, like yourself. I've done a lot of different jobs, over the years, but I leave the questions regarding code, to the pros.

personally, regardless of any code provision, I would prefer a PROPERLY installed donut over a shielded no-hub coupling

NEVER NEVER NEVER bury a 'fernco'

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

i'd prefer a 4 band shielded no-hub coupling over a donut.
either way is fine..
don't forget to put a cleanout tee 18" above the floor.

OK, well I'll find out where the break is and that will determine if its a donut or a no-hub connection.

I already had planned the clean-out, but is the 18" clearance from objects or from the floor? The code wasn't clear to me on this either.

I plan to use a long sweep for the vertical-horizontal transition. Do I back-fill to support it or should it be find once its set in the concrete?

the 18" clearance from walls is a code requirement to allow access. 18 above the floor is a convenient height for the operator of a snake who may want to snake upwards as well as downwards.

Well I'm glad I opened it up because the elbow was cracked and completely detached:

[www.dropbox.com]

I cleared out the rubble and the remaining hub and pipe appear fine, congested, but fine.

[www.dropbox.com]
[www.dropbox.com]

I chipped away the shards of pipe sticking out, but there is a ring inside the hub caulked in still. I was able to clear out the previous hub caulking with a 5/16" drill bit, but I don't have that clearance here. I have both a donut and 4 band hub on hand. I also have an unused diamond cast iron sawzall blade that I would prefer to return. Is there a good way to clean the caulk out from this standpoint? Propane torch? Prying or breaking out the remaining pipe?

Can you get at it with a right-angle drill?

a torch will melt it out.
kinda smokey at the end when the oakum starts to burn so open a window and have a fan standing by.

Well it was a bear, but I got it cleaned out and the donut in. The short clearance made it incredibly hard to pack in. The pvc work was quick and easy after that, but I had to wait a day to do it. I was seriously beat up and tired once the donut was set. I packed gravel under the elbow to support it and have been using all the attached fixtures to check for leaks. Everything is dry and so I'm going to pour the concrete today.

Thanks for the help everybody.



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