Plumbers, Foundation folks?

[txav8r]

We have spent the last two and a half weeks dealing with a plumbing issue under our slab. The slab is post tension cables with deep beam grid on piers. My toilet vent stack "T" into the stack apparently has separated just below the slab. This comes of course just a few months after totally repainting the hiuse and installing new carpet and pad in the master suite.

Our local plumber who we trust, kind of became crusty about it not wanting to keep any kind of schedule as he loves the high dollar emergency service and works 7 days a week, pushing less urgent situations down the list. He has ran a snake down the main line and it is clear, but the master bath branch has the one known issue and he verified that with a camera. We wanted him to check back up that branch just to verify integrity before doing what has to be done to repair. We have contacted a tunneling company to see what that would look like opposed to pulling new carpet, jackhammering the slab, digging and dumping yards or more of dirt in our house to repair.

I stopped the separate contractors yesterday as they didn't seem to give me a timeline. I contacted and scheduled a larger in town plumbing company that can handle all aspects in house.

Any experience, advice,or suggestions?

 

[Julian]

Sorry...no help here.....other than "I hate plumbing problems"

 

[itsdgm]

Sorry to hear that Mel. Please take pics if you can. I'm on a tension slab too and will be following your progress. In our neighborhood there have been a ton of slab leaks, but I haven't heard Of anybody having a situation that required digging into the slab. I'm not at all sure of which pipe you're referencing that has separated but I was always assuming that all of my plumbing that goes into the slab is encased in the foundation and not sitting below. Except for the line out to the sewer of course. But I haven't ever watched one being poured. So, I'm sending good vibes your way. Keep us posted.

 

[1rjclark]

First let me start off with Wow. Did I say Wow. Ok........ With me being in Northern California I would not tunnel under my slab. But that my be doable in your area. If the waste/ vent connection is close to the outter edges of your slab then with a qualified company with proper garuantees I'd consider this route. Otherwise go thru the slab on top. Maybe your larger plumbing shop has the capabilities to scan the concrete in the work area to mark where the PTC are , then the concrete can be chipped out, repair made and tested ect. However why did this plumbing joint fail. This joint should have been tested with 10' of head/ or 5psi during the underground plumbing inspection. glued joints and mechanical joints that are apart of a properly tested system don't come apart so easily. If you go with the chipping concrete way, prepping your area and clean up is what's gonna be essential. So make sure your contractor can leave your home better then when he/she got there.

 

[rkluck]

I know this sucks for you. I have seen the house slabs poured (our house was just recently built) and just did a little research as well. One key item that 1rjclark brought up is why did it fail in the first place. No matter what this needs to known and corrected. I don't know about your area but it seems like the preferred method is to tunnel under thus avoiding the tension cables and concrete issues. You can cut from the top but absolutely must avoid the tension cables which means identifying the location up front. If these cables break it can be dangerous and expensive to repair. If you are hiring a plumber to this I think they would be able to provide the pros and cons of both for your specific situation. Sounds like a lot less intrusion to your home if you tunnel. Let us know what you do and how to turns out.

 

[txav8r]

Most slabs in our area are only 4 inches thick in non bearing areas of the slab. Beams are often under load bearing walls or on a grid pattern. My slab was designed by an engineering company. I don't have any water lines except the two lines to the two areas of the house with distribution above the slab. But those two lines are sleeved, so water breaks should never happen. As far as the sewer break, my house slab combined with the beams, sit on 67 piers to prevent ground movement from allowing the slab to settin in dry times and crack. But it is designed to ride on top of the earth when wet conditions cause the ground to swell. We are on expansive clay soil, so an engineered foundation is preferable. As far as what I can tell from research, nothing you can do will prevent limited movement. And if it lifts, and the sewer lines that run through the beams, will lift them, and the lines outside the beams but under the 4" slab, have the weight of the earth on them and can easily be separated. So this is not a fault of install or anything else. Funny, my plumber originally wanted to k i.e. Who did the install, then when I asked if he was guaranteeing his work, only for 30 days! The reason...the ground moves. I have photos of every pipe under my house and I know How it was installed as I was the GC on the job. Yes, I had the plumbing pressure tested prior to the slab being poured, and was fine 13 years ago. @itsdgm , unless engineering requires an incredibly thick slab, most of your plumbing is installed in the full, before the foundation is poured.

 

[Murf'n'surf]

Have you looked into relining the inside of the pipe?

 

[txav8r]

No @Murf'n'surf , it wasn't offered as an option. But it is in the connection sweep that has separated from the vent stack and it feeds the drain below it.

 

[Murf'n'surf]

I'm not a pro but they line the inside of pipes down here to prevent salt water from entering the sewage lines returning to the treatment plant. Anyway, pipe lining is available but not sure how it would help a structural problem. It's likely your pipe will settle/separate more over time.

Like I said, not sure it's a viable solution but may be worth your time to investigate. Here's a company I've seen working locally.

http://www.insituform.com/Locations

 

[rkluck]

I read about these slabs being built to move as you described. I saw were the plumbing should have a rubber sleeve over everything to avoid abrasions and issues due to the slab movement. Maybe that would be another thing to consider if they are not already sleeved. I liked the idea of the lining as well since it would have the ability to move independently of the outside pipe. Sorry you have to deal with this but very interested in the outcome.

 

[txav8r]

I'll keep you posted. I don't see how tibia possible to sleeve a hard connection like a toilet flange, tub/sink/shower P trap. Those are hard connections. No matter the length, these are 1.5", 2", 3", and 4" fixed drains. As I type, I know they leave a sand bed gap on tubs and showers, but sink and toilet drains don't have that. None of this would be code in Texas when the house construction started 14 years ago or when it was finished. And I'm pretty sure today wouldn't be either. But I am certainly going to check into the idea of a flexible connection. The trouble is, the break or disconnection is below the slab, so you have to be rigid at some point. I have a second opinion coming Friday.