Hi Folk! My 80 yo dad owns a ranch home on a congrete slab with plumbing embeded in the slab. 2 months ago his cold water 3/4” copper domestic water pipe sprung a leak. Noticed by wet carpeting. The plumber cut and rolled back the carpet, jackhammered the concrete, found the leak and replaced the section and poured new concrete. DONE...not so fast. A couple days ago another wet spot a couple feet from the initial leak. My thought to him is to run all new domestic lines now overhead. Cut a swath in the drywall ceiling and drill thought ceiling joists all the way down to his master bath. Place nice thick insulation on top of new pex tubing, reconnect to the kitchen, and two baths further down the hallway. I think he will continually be chasing these deteriorated pipes. The copper pipes are in direct contact in the concrete. House was built in the late 50’s. Thoughts?

Too many homes have copper rolled under the slab and eventually they all will be replaced. Uponer PEX seems to be choice of Contractors and Plumbers. It must be installed by a qualified plumber or problems will surface again. Find Plumbers that have success in your area and get a minimum of three bids. GOOD LUCK my friend.

yeah, replacement is needed..

if you do the prep work of cutting the ceiling and making holes for the piping to fit, you can save yourself some money..

when running pipes overhead like this i like to do this...

using a 1 1/2 inch hole saw, place the 1/4 inch center drill bit firmly against the bottom of the joist. drill thru the joist but you will only be making a small smile (part of a circle) in the very bottom of the joist.
so between the smile and the strapping space at the bottom of the joist you will have plenty of room to fit a pipe with insulation on it.
you can now take straight lengths of pex, slide pipe insulation on them and raise them into place.
of course you can lay insulation on top for additional protection.
the new sheetrock may touch the pipe insulation but that insulation will just compress a little holding everything nice and snug.
i've done this dozens of times with great success..
do consult with the plumber about layout of the piping.

Packy you’re always right but I question this advice to notch out the bottom of joists or perhaps roof support trusses... drilling thru center keeps them stronger, and in a ranch house on slab why can’t he just run them thru attic on top of the joists? Yes will need insulation. This way requires less drywall cutting and no weakening of the structure.

i have been told that a 3/4 inch smile on the bottom of the joist really does nothing unless the joist are undersized to begin with.
if i'm wrong hopefully someone will correct me.
anyway.. freezing in the cold weather and sweating in the hot muggy weather is always a concern.
that's why i do them this way.
100% insulated piping with no worry about where they go thru the joists.

Thanks for your reco Packy. Was thinking of doing the same thing as you wrote. I forgot to mention dads house is in northern NJ, hence the insulation concern. Would it be prudent to foam pipe wrap the tubing plus like a nice batt of roxul on top of that? Also I believe Wirsbo only sells plastic 90’s and plastic connectors now (I believe they sold both brass and plastic in the past). I know PEX tubing will expand upon freeze with no issue-do the plastic 90’s and such take the force of a freeze without cracking? It will be 3/4” for the run to the bathrooms. I have always read it is better to drill a smile then cut a square cornered knotch in joists.

the pex joints whether plastic or brass are the weak link in the system when it comes to freezing.
even if the fitting were able to expand, the ring that secures/seals the joint would be compromised.
foam insulation is OK but it is not so great at 90 deg bends.
i would just use 7/8 ID armaflex type slide on insulation.
just be very, very fussy with the pipe insulation and whatever you lay down on top of it..

Dad will continually chase slab leaks, a re-pipe is in order. If it's a one-story ranch house, why not just re-pipe in the attic and lay the new pipes on top of the ceiling joists? Seems like a big mess to get into ceiling repair and cutting every joist.

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Not a plumber by trade but a fierce DIYer

Probably not a problem in NJ, but in the West many homes do NOT have attics or crawl spaces. Concrete floor, living space, ceiling, rafters, roof, one on top of the other.