Slab Leak Help

Hey all,

So I found out this week that I have a broken sewer line under my slab (on-grade, no crawl space or basement). It is likely responsible for a depression and settlement that has occurred in the center of the kitchen. Has anyone ever had to deal with this before? I have all sorts of questions about how to go about fixing this. The insurance adjustor has already been out to look at it and it seems like they'll help with the repair of the leak and replacing the damaged concrete and flooring but won't do anything about the settlement of the slab or central load bearing walls or kitchen cabinets.

• I'm inclined to tear up the entire downstairs floor and replace the entire length of the sewer line, not just repair the break. I don't want to ever have to do this again, especially after putting in new floors, etc. Does this seem reasonable? Should I replace the water lines at the same time?

• Anything I should know about dealing with the insurance company or contractors? This is the first time I've ever had to file a claim.

• There seem to be a number of ways to attempt to re-level the slab once the repair is completed: poly jacking, helical piers, self-leveling cement, etc. Any experience with any of these? I do need the central load bearing wall to be raised back up as well.

If the collective has any experience here, I'd love some pointers. Thanks!

I don't really know anything about availability or expense, but there is a method of drilling holes in the slab and pressure-pumping concrete grout into the void to raise the slab back to the right level. I'll see if I can find info for you.

When Duke finds that pressure grout system I'm interested; the slab for my front porch has a crack and is about 3" low in one corner. I'd sure hate to have to replace the entire porch slab. PSA, kiddies; that is why you install gutters and when you do you think very carefully about where they discharge. Rainwater runoff is the #1 cause of that type of problem, the water softens the ground under the slab then pop!

As far as repairing the leak itself, there's a method which uses inflatable epoxy coated tubes, no digging required. No affiliation, just one company that popped up in a Google search: http://www.plumbingprofessors.com/sewer-issues/epoxy-pipe-lining-cipp/ A friend has a similar problem and here's the deal: they have to come out and run a camera through the pipe, at that point they can tell you if it's repairable. If so it's something like $300 a foot. There is typically a charge for the camera service, I don't know if it's applied toward the repair.

Oh, and if you do decide to go with digging it up by all means replace every water pipe you can find!

I had that done with my sewer, fortunately, the cause was tree roots just over the property line. City paid for it. A dozen years of never knowing when the basement would erupt in a tsunami of bum boats, solved.

People get all freaked out when I tell them I have to open up a wall or a floor to get at a pipe. Calm down, its not a big deal. Use a hammer drill to drill some holes and a sledge hammer to break off big chunks of concrete. You can use a concrete blade on a circular saw, but that leaves a smooth edge cut. A broken up edge is better for holding the new concrete in place. Don't worry about where it goes under walls, because you can get at it from either side of the wall. Expose as much of the pipe as you want to replace and then call the plumber. When the new pipe is in the ground, make sure the ground under it is supporting it everywhere, and then fill the hole back in with sand and dirt with no big rocks. Compact it every few inches as you fill the hole back in. If its close enough to the new concrete, you can install pipe hangers that stick up out of the dirt and when the concrete is poured, the new pipe will actually hang from the concrete as well as be supported by the ever shifting dirt under it. The busting concrete and filling it back up is the grunt work, so no need to pay a professional to do that. A few years ago, my BIL in Florida had to deal with the same thing. I talked him thru the whole job on the phone. He is a cop, and if he can do it, I'm sure everybody on this forum can do the same.

If I replace the entire length of pipe, that means demo-ing a path all the way across the kitchen, through the living room, and through the laundry room so it's a non-trivial amount of destruction. I'm also concerned about how to level the entire downstairs once the repairs are completed. Does slab-jacking/poly-jacking risk damaging the pipes under there? Do I need to wait for the soil to dry out before getting the floors leveled?

Thanks for the input so far guys. I'm a bit overwhelmed by the scope and potential cost of the project right now.

I watched a driveway being leveled using the method Duke described. It took them maybe an hour to do. They rolled up, drilled holes through the driveway. Fired up the mixer/pressure system and the concrete floated up almost instantly. Then just as quickly they were gone.

Mudjacking is the term you're looking for.

As for the sewer pipe, depending on its condition (if it's crushed, or is still intact but leaking) there's a method of lining the pipe to seal it - a long fiberglass 'sock' is inserted into the pipe, pneumatic tube is inserted inside the sock and inflated to hold it in place, and resin is injected. Once the resin hardens the pneumatic tube is removed and you have a nice, smooth sewer line that doesn't leak. Look up 'sewer pipe lining' or 'trenchless sewer repair'.

I've been on projects lifted by mud pumping that blew my mind. We installed helical piers around the perimeter foundation of a chicken processing plant that was built over a creek that they "thought" was diverted around. After we finished our work Slab Jackers came in and lifted the entire interior slab, with all of the machinery and equipment still inside, around three inches. Quite impressive. We worked on several projects together over the years and I was always impressed with the results. It's just outside of my area of expertise so I can't really say what affect it may have on underground utilities but I have no doubts that it can be lifted.

FWIW the pipe is completely broken in two and the ends don't line up anymore, so the lining repair probably isn't an option. Also, the first break was as far as the plumber could get his camera so at this point I don't know if there are additional breaks further down the line or not :/

I'm wondering if you're not on a sinkhole. Ground starts to give breaking the pipe, pipe leaks, slowly exacerbating the issue due to erosion and causing the rest of the floor to sink and you are where you are now.

I've been under a lot of houses and unless your slab is severely sub standard it's very difficult to get them to move that much internally. Of course I know how damaging water can be, especially if a leaking pipe goes unnoticed for a long time.

Any way just something to think about, I know it's certainly not uncommon closer to the Appalachian mountains. Not sure about over on your side.

Run the damaged waste lines to the outside of the slab, and fresh waters thru the attic?. If insurance is involved I would definitely call a good plumber. Tr8 is on track. This will be messy, and labour intensive.

As far as leveling the structure and the floor again, thats going to depend on the insurance companies most cost effective solution. Inevitably there will be things that are not covered. The plumbing is where you can save the most money because of the grunt work involved. This means some of the money designated for contractors to dig up the slab can go thru you to things that are not covered. I know it seems like a big deal. I know it will make a mess. Once you get the concrete out of the way, its just like digging a trench across your yard, except the dirt you will be removing will have already been disturbed so it will dig much easier than virgin ground. Back fill will be easy because you already have it laying next to the hole. Fixing the concrete may be part of the leveling solution anyway, and if not, at least you don't have to stare at a trench in your yard for the next 3 months as the grass tries to grow back. The bog question is why did this happen. How old is your house? If its new, then you are dealing with improper compacting of the ground under the slab. If its an older house and it just started to happen in the last year, you have something more sinister going on under the slab. I've done a few houses where the whole house was lifted up 10 feet in the air and a new foundation was installed under the house. Most were because of home heating oil tank failures contaminating the soil around and under the foundation.

House is 38 years old. No idea how long the pipe has been broken but we did have a pretty big earthquake a few years ago. The good news is I had an engineer out to look at the settlement problem and he indicated that all the exterior walls that have footings are fine and have not settled at all. All the weight of the 2nd floor is on this central load-bearing wall that apparently doesn't have footings which may be why it's sinking.

TRoglodyte wrote: Run the damaged waste lines to the outside of the slab, and fresh waters thru the attic?. If insurance is involved I would definitely call a good plumber. Tr8 is on track. This will be messy, and labour intensive.

Definitely a possibility. My friend and I researched doing this, the main reason we decided against it was the pipe coming under the slab has a downward slope, obviously it needs this. To run the pipe outside would mean excavating a HUGE hole under the slab in two places (one upstream of the break, then one under a bathroom), then running a deep trench (~6 feet) around the house to preserve the downward slope of the pipe. Renting an excavator and having to properly fill the holes to prevent future slab problems would be VERY expensive. (She's in the city, they have to sign off on big projects like this. Get caught doing it without a permit and inspections can be VERY expensive as well.) I'm not sure what she's planning to do. As it stands, the only real big problem is the washing machine will back up.

By the way, this type problem is why I don't like slab houses. A friend in Charleston had a water pipe break under the slab, the water eroded a big hole under it. They wound up having to jackhammer the bathroom floor up, remove all the fixtures to allow for the repair, then refill the hole. The water leak was so bad the back yard was mushy, didn't help that it had rained a good bit as well. The concrete truck got stuck in the back yard, they had to bring in a bulldozer to get it out, this pretty well destroyed the grass in the yard. The truck was not able to get to the bathroom window so they set up a wagon train of wheelbarrows going through the house. That meant extra people (more $$) and even with laying down a lot of plastic the carpet was damaged, along with some of the sheetrock. No thankee; I buy only crawl space houses!

I would not replace any water lines under the slab. I would move them so they are above the floor level.

Slabs are terrible places for live water lines. There is no need for them to be there.

I am also not sure I would replace all of the sewer line.

It is highly unlikely the pipe failed.

If a joint failed due to poor workmanship, it is also unlikely there are very many weak points. It is not a pressurized system, so even when glued joints are questionable, they generally serve their purpose.

So, the only remaining failure potential is from structural, subterranean movement, and shifting. Sounds like this is what caused the break you are dealing with.

The problem is, replacing the pipes will not prevent future problems. If the house is settling, it will shear a pipe anywhere it darned well pleases, regardless of whether the pipe is new or not.

It's a bit of wasted effort.

I would replace the broken section, then pressure test the lines before tearing up all the sewer lines. It you can't build pressure, send a camera down the lines to find the issue.

If by chance you have a condition where the workmanship was so bad that multiple joints have failed, then it is time to replace the lines.

Curmudgeon wrote: No thankee; I buy only crawl space houses!

That used to be my perspective as well.

But there are a LOT of ways to screw up a crawl space house too. The biggest is thermal efficiency and moisture control (and termites).

It's pretty hard to build a slab house that has water sitting under it. Quite easy to do on a crawlspace. Mold, etc. is a MUCH bigger issue with crawl space houses.

As the quality of the constructors declines, I have changed my position.

I'd rather buy a slab house now (although compaction is the 1 huge question mark).

Unless I am building it and know what I've got.

'Unless I am building it and know what I've got'.

And that's why I don't do slab houses. It's possible to screw up anything, but repairs are MUCH easier on a crawl space.

Curmudgeon wrote: ... but repairs are MUCH easier on a crawl space.

Right.

And errors are MUCH more common, and often unresolved, with long term structural and health repercussions.

I've been under hundreds of houses, and only seen 1 I felt was well executed, once all the trades were considered. Errors are common, and costly.

Concrete is essentially a single trade problem, and errors are pretty rare. They are costly too.

It is possible to verify the quality of the work/ compaction, etc on a slab.

I have no problem with your preference, I am simply sharing that I have come to prefer something else.

There are also regional differences (soils, climate, etc) which make one form of construction better than the other in particular regions.

In the end, I am more interested in a well constructed building suited to last for a century then a poorly constructed one that I can crawl under so I might be able to fix it.