Help plugging water supply line under slab?

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#1

Plumbing question: mods, feel free to move if I’m in the wrong area.

Short version, I have a small leak in the supply line under the slab for a bathroom sink. Ultimately, I’m going to replumb the house soon with PEX, but in the mean time, I’d like to stop that leak. Any way to do that without digging? The redneck in me wants to pump foam down into it…
“What about the manifold” you ask? Well, this 50’s house was remodeled decades ago, and neither me nor a very expensive plumber could find it. I’ve seen treatments offered by plumbers to “fix” leaks under the slab with various epoxies, but I haven’t found where I could purchase these myself.

Any help would be awesome!

#2

I had a similar leak under the slab, making a warm spot on the floor (hot water line).

I hired a plumber: they pulled back the carpet, jack-hammered the slab, dug out the dirt, fixed the leak, refilled the hole, patched the concrete, and reset the carpet in about 4 hours.

That was easily half the time it would have taken me to do the same.

My advice: hire a plumber.

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#3

Sound advice. We had a plumber open a small exploratory hole in the slab… still couldn’t find it… so they dug under it. It took them a long time to find it under the center of the house under some very expensive hand scraped hardwood floors that are throughout the game room, living room, and hallway. It was worth the digging to not have to redo those floors.

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#4

@Raymond @HankCowdog all too true… but the plumber didn’t recommend digging or tunneling ($5k) for the exact reason that there could be more than one leak and, given the age of the house/plumbing, we’d likely be looking at more leaks in the not too distant future. He, and I agree, suggested replumbing the main line into the house, which is totally doable without the $7k price tag. I’m not scared of the replumb, just hunting for a way to stop that leak while I do the replumb work.

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#5

So. Am I understanding you have a 1950’s house that is NOT pier and beam?

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#6

Yep! I’m around the corner from the Space in Farmers Branch

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#7

You could theoretically turn it off at the main every morning before you leave. Providing no body is home. Have you looked at your home owners insurance or home warranty company for potential repairs if even temporary.

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#8

Last time, I just rented an electric jackhammer. I used a stethoscope to make a best guess on the leak, jacked a small hole, once I identified the exact spot, I jacked a hole big enough to get tools into. Cut/patched/silver soldered, poured in flowable fill, and fixed tiles.

Not hard, but tedious. But plumbers charge real money to fix slab leaks, so I saved about $2500 with one days work. Pretty good pay.

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#9

This is the first call to make.
I had a soil/waste line break under the slab about 16 feet from the front of the house. Homeowners insurance paid for the tunneling, piers, but not the actual pipe repair.

Just curious but is your 1950s home still plumbed with galvanized piping?

#10

Did many homes of that era have a manifold? I interpret that as a “home run” to each outlet and more a modern PEX scenario.

#11

I would’ve spent the $2,500 at the doctor afterward.

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#12

@TBJK exactly that, they might cover the tunneling, but they won’t cover the repair, which was fairly pricy on its own.

@TLAR, I’m betting some of what’s under the house is galvanized. What we’ve found in the house is copper.

@jphelps, I’m trying to get plans from the city (Farmers Branch keeps that kind of thing), but yes, it might not have a manifold. The plumber thought it would have one from other indicators and might just be under the slab

#13

Ah, I was curious because I wonder about my own home in this regard. I need to see if I can obtain plans from my city (Coppell)

#14

Some copper plumbing houses did home run all the under slab lines, and have a manifold of soldered tees and elbows, usually about a foot above the slab, hiding somewhere behind a cabinet or Sheetrock. Personally, I doubt the plans filed with the city are ever detailed enough to find it, but can’t hurt to try. (Aside from the risk of a field/inspection approved deviation, that causes you to open up the indicated place, and not find it.

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#15

anyone know where I could find this tool? Google has been no help.

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#16

Home Depot sells a version of it…

He also didn’t technically solder that right. Solder is supposed to be flowed from the bottom to the top. This is supposed to let the flux exit without voids in the joint.

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#17

here ya go:

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#18

There are some plumbing companies that have borescope type devices that can locate the leak. Some of them also epoxy the lines from inside. Never used them - but its out there.

I suspect I’ll have to endure tunneling at some point on waste line.

#19

Tapper’s stethoscope deployment for leak detecting was great!

waste line - the use of a plumber colonoscopy camera works great - plus the camera has a built in “odometer” to track how far you are feeding it into the line.

I’m not into the Leavenworth hard labor of digging and tunneling in Texas soil (but I wouldn’t let them puncture the post tensioned slab either) so the folks from Du West foundation had 2 guys dig using shovels to dig the access hole and corded Bosch bulldog with a chipping blade in it to help with the tougher denser soil clay & a lot of shoveling to remove 16 feet of tunnel space.

#20

Thanks for all the advice guys!

I’m going to rent a trencher this weekend to lay a new supply line into the house and run new lines to the kitchen and bathroom from this new manifold.

Viega 50243 1/2-Inch PureFlow Zero Lead Poly Alloy PEX Crimp Manabloc With 24 Ports - 15 Cold 9 Hot https://www.amazon.com/dp/B008J3TSH6/ref=cm_sw_r_cp_api_tuyGAbCPBQ7QX

I’m debating putting the manifold in the hall closet with the water heater. Little more work, but it would give me access to shut off water without having to get in the attic or open a wall.

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