Unique repair solution for underslab water leak

Mechanical Engineer shows new way to repair large section of underslab copper tubing.

[@Jc-do4fy]

no need to bust a hole in the slab if you can simply abandon and re route the line. We just went through this.

[@Sheila6325]

I can't think of anything worse than a broken, or leaking pipe, under a concrete foundation. Looks like I have a lot of research to do before my well is dug and what to do about never having that problem. At least now I know what I have to ask the person that will have to deal with my concern over this issue. I'm sure glad I saw this before we started digging. Actually, what is really weird to me is, I've never heard of this before. I know about building, and I've never heard of anyone dealing with this problem before either!!! Wow! Thank you, Sheila

[@Newlinjim]

install a manifold for PEX route PEX through PVC.

[@BombsAwayMineCraft]

I'm going through this right now. It's such a nightmare.

[@aapp953]

Any thoughts on new plumbing lines getting pin holes that look like drill marks from inside the tubing leaving a red dot at the exit hole ?

[@ec8490za]

The average homeowner will not know where the manifolds in the home are and will need to hire a locator to find where the lines tie in together. And what happens if their is a kink in copper line under ground? The pex will not make it through. You can not burry a shark bite fitting (push fitting) under ground let alone set concrete over it. You can only silver solder copper under a slab. That shark bite will fail. Save yourself the headache and re-route the line.. better yet re-pipe the home through the attic and insulate the lines. The temperature in those will only be warm as the water is stagnant. When you run water, you are pulling the cool water from the city meter which is buried under ground. I understand your point of view and trying to help people save money on repairs but that is not a long term repair. Bite the bullet and get it done right and warrantied by a licensed professional.

[@engineershomeworkshop2692]

Thanks for your thoughts Eddie. Yes the push fittings will eventually fail. . . so did the original rigid copper piping. Manufacture dosn't recommend using push lock fittings the way I did, however, the manufacturers engineers have a different conclusion but the insurance and legal interests dictate what a product is capable of . . . product literature goes through many filters. Yes the average home owner wont know where the lines run. Things need to be sufficiently known before proceeding with anything. As for the rest of it . . . your thoughts represent your perspective well and I thank you for posting. My perspective comes from a different place then yours does.

[@garycallihan4206]

I helped a friend recently here in northern CA; we re-piped, as you describe, and introduced new supply valves and more. All PEX...and clamps. I was the short one and the designated attic monkey, at 69 years of age.

[@senseisecurityschool9337]

Update 4 years later - you CAN use push fittings underground - if you wrap them with silicon tape.

[@whiterock1865]

Awesome solution, finally I was looking for just this solution. Can you give more video on actually cutting through the slab?

[@engineershomeworkshop2692]

Actually, I used a rented jack hammer. Never thought to video that part of the effort. Glad this video gives you another possible option.

[@Cosmic_Soul]

Copper pipes are the most durable material for domestic plumbing, but not in every region on Earth. The leaks are not due to impurities in the copper pipes; it’s the salty air in Florida. The green/blue coating on the copper pipes in this video is the proof. Florida is still not so bad, there are many seaside areas in the world where the salty air destroys electronic gadgets like TV’s and stereos. Also, the composition of the earth and sand under your house matters. When my dad was building his house in Karachi, Pakistan (which is on sea), he made sure that the sand to mix in concrete is coming from inland and not from seaside. Also, he made the contractor wash the gravel stones with sweet water before mixing in with cement.

[@garycallihan4206]

Agree. I just performed a completely changeover to PEX...via the attic and more to address an expanding pooling of hot water, underneath the kitchen, with a slab house, one story fortunately. Two old men, 68+, 2 days a week for 3 hours/day, for 9 weeks. Air pressure tested prior to activating water into the lines. I was the "attic monkey", as I was younger and more agile. This was here in northern CA, 30 miles east of the dirtbag city of San Francisco, with the residence within 1/2 mile of the Delta rivers and tributaries.

[@Cosmic_Soul]

@@garycallihan4206 Small piece of advice, do periodic checking for minor drop by drop leaks with PEX. A friend recently moved into a new house here in Ontario, Canada and they have at least 6 visits by the builder for very tiny leaks in PEX joints.

[@littlecopperstypek7336]

You buried a 🦈bite, oh no 😢🤣

[@562handsomemike]

Another possible cause I have seen is Corrosion Erosion from excessive velocity. Especially from hot water return lines with the wrong size pump (3/4 h.p. Instead of the original 1/2 h.p.)

[@SeanBaker]

Gotta do what you gotta do.

[@reasoningtruth]

How cool! I love out of the box thinking!!! I wonder if the opposite can be done. Put a 3/4 90 scheduled PVC on the outside of the copper. Using water to bore the hole and the copper to guide the PVC. When you get the PVC through to the other side then pull the copper pipe out with a wench of some sort. (Another out of the box brain fart. But you caused it)! LOL

[@garycallihan4206]

I can reveal to you that effort and motivation will prevail beyond brief failures. It is amazing what the mind and motivation can accomplish.

[@kevinh.7566]

That is a GREAT idea - did it bore thru fairly quickly? I've only got about 15 feet to go thru. Any wisdom that you can add?

[@reasoningtruth]

@@kevinh.7566 Remember in my post I said; " I wonder if the opposite can be done." Wondering isn't doing, but in my wondering mind's eye it would seem to me to be quicker and much more accurate being as you have a guide that already has the borehole partially bored out. Just plug the copper pipe, so there won't be lost boring water running through it. You're going to want all the water to be going between the copper pipe and PVC. That's where the boring needs to take place. Any water going through the copper pipe will be lost water and even more so, lost pressure!

[@senseisecurityschool9337]

@@reasoningtruth That's a cool idea. To avoid washing out a lot of extra soil, and to make boring easier, it would be ideal if the old copper pipe was left open to allow the water to flow back out. Maybe connect it to a garden hose to dump the water wherever you want it to go (ie outside or down a drain). The question is how to put water into the PVC while leaving the copper open at the same end. That could involve a reducing slip coupler with an O-ring in it and a T fitting. Maybe a Sharkbite style reducer, with the release ring permanently pushed in on the smaller side so it can slide up the pipe more easily.

[@reasoningtruth]

@@senseisecurityschool9337 , It's going to be a watery mess alright, but you can, like you said, divert the exhaust side with a hose of some sort. But you got my weird idea, alright. Hope the inlet side is outside, or you can get some sandbags or something to corral the water outside somewhere. I guess I need to eat more beans for more brain farting. Sounds like you're a good pick for the inlet person. I would have never thought of that one! Shazam!

[@kevinh.7566]

5/5/2023 - I am up against a similar situation RIGHT NOW. My main 3/4" copper water supply from the water meter is leaking (fast) under the slab - was considering running 1/2 pex thru it to minimize destroying my kitchen floor - but I'm thinking now (after reading the comments) that this may not be a good direction as the flow would be severely diminished. Kinda like the idea of using the old copper as the guide to water jet a path thru to the issue area - only about 15 feet to the destination . . . any advice would be greatly appreciated.

[@engineershomeworkshop2692]

Well, the hardest part of my engineering career was to get others to take the emotional/psychological assumptions out of the decision making process. You say the flow would be severely diminished. It would be restricted. . . eliminate the emotion word "severely". Replace with a percentage if you know how. Depending on your incoming water pressure and water consuming deices, you may be willing to live with the reduced flow. EX: Would it bother you to have a dishwasher take an additional minute to fill up or would it bother you more to do the extra repair work. Regardless, a main line that effects the whole house should get a high priority to the original 3 /4" size. (A water jet works great in some areas, not so well in others. . . beware of slab footings under internal load bearing walls.)

[@jorgecallico9177]

The Pex is measured by the OUTSIDE DIAMETER my friend. Not the inside as are American copper pipes. Thus you're not going down from 3/4 to 1/2 an inch but from 3/4 down to 3/8ths!!! Reducing your flow rate by at least 75%! Unacceptable. As a plumber, I'd get sued for doing what you did. Since my first trade was tile contracting I would have recommended re-piping under the slab with One inch Pex both Hot & Cold. Plastic is cheap and the extra thickness just allows more flow. Your current system will be ruined as soon as one major appliance like a washing machine gets turned on. You won't even see a trickle come out of any other faucet. And if you have a claw tub? OMG, your whole system will quit flowing. Again folks TAKE NOTE!! PEX IS SOLD BY OUTSIDE DIMENSIONS!!! NOT INSIDE. Whenever possible, choose at least the 1 inch Pex for all supply pipe up to the water heaters and most rooms afterward. I know that many guys like the manifold with dedicated lines but this is just wasting tons of plastic pipe which while cheaper than copper still isn't exactly free either. What good does it do to spend less per foot on PEX but use over twice the length you did with the copper? Most prices I've seen comparing the two show Pex at roughly 60% the cost of copper. Of course this isn't quite true either BECAUSE PEX IS SOLD BY OUTSIDE DIAMETER AND COPPER S MEASURED BY THE INSIDE DIAMETER!!! So it does no good to say, ''Pex is only 60% the cost of copper''. Copper WHAT dude? If you want the same or better flow rate from Pex as you did copper? You must UPGRADE THE WIDTH OF THE PEX!!! This can not be overemphasized. 3/4 Copper ='s 1 inch Pex in flow rate!!! One inch Copper ='s 1 & 1/4 in Pex which requires V expensive tools to work with. in short, Pex can help but it is not the bargain that the sales reps claim that it is. Hey, they just SELL the stuff. I've installed the stuff. For YEARS!

[@engineershomeworkshop2692]

Jorge, of course the diameter is substantially reduced. As I had mentioned. . . this line only went to the washing machine and water heater. As a personal choice, the time increase for filling up the washing machine is more than acceptable (required hot water pressure and flow are just fine, certainty a variable depending on each situation) . . . for other situations, as you pointed out, it wouldn't be. Regardless, these are obvious issues. This repair is not intended to comply with any generic building code or professional legalities . . . it's intended for a custom work around for a higher calling. . . the knowledgeable homeowner.

[@tacklebox6239]

@@engineershomeworkshop2692 if it looks like a hack job and sounds like a hack job… it’s a hack job. Just spends the money and repipe the house. Besides that money you’re saving, you can’t take it with you when you die. Fix the old house up so whoever inherits it doesn’t have to worry about it. They’ll just have to repipe it anyways.

[@senseisecurityschool9337]

Copper, pex, and PVC are ALL sized by the outer diameter, which is 0.875" inches for "3/4" pipe. That's why a 3/4" push fitting fits any 3/4 pipe - copper, PVC, PEX, you name it. Because they are all sized by the OD. The PEX does have a thicker wall, so smaller inside diameter - BUT the law limits the flow rate allowed for a faucet aerator ANYWAY. 2.2 GPM is the highest in the US, 1.2 - 1.8 in California. A 3/4" line that can do 6.5 GPM isn't doing you much good if your fixture can only flow 1.2 GPM. It only matters if you're using three fixtures at once off that same 1/2 PEX.

[@tacklebox6239]

Why not just spend the money and fix it the right way by doing a repipe? You said it yourself you’ll need to address it again when you get a another leak. Stop being cheap and giver yourself and if you have any family in the home a permanent solution. You’re just wasting time which is much more valuable than money. Besides none of that work meets the minimum code requirements.

[@plumbingimmortal1709]

LOL typical engineer, has no idea what they’re doing

[@engineershomeworkshop2692]

Typical response from those that only know enough to follow a well worn path.

[@elijah3807]

Don’t do this.