broke off galvanized pipe under slab..need help

hey all,

have a few questions about a repair i just did. i broke off a cold water line to my master shower. it broke under the slab.

so i jack hammered up part of the slab, re-threaded the pipe, and now have a cap on it. i have a few questions:

1. i want to use a dielectric union under the slab. can it be buried?

2. there was a vapor barrier between the soil and slab. i busted thru to get to the pipe. can i just put some 6mil plastic down there, would that work?

thanks!

Why would you put a union under the slab? You never want to see that again.

Since it is cold water and not in the house, you could get a Schedule 80 PVC threaded coupling or female adapter and start your new run.

If PVC is a code problem under the slab, then find Schedule 80 CPVC. You can get threaded couplings, elbows, female adapters, and pipe at Grainger, and probably at plumbing supply houses.

I would change to CPVC under the slab and run it all the way to the shower.

motlot77 said:

hey all,

have a few questions about a repair i just did. i broke off a cold water line to my master shower. it broke under the slab.

so i jack hammered up part of the slab, re-threaded the pipe, and now have a cap on it. i have a few questions:

1. i want to use a dielectric union under the slab. can it be buried?

2. there was a vapor barrier between the soil and slab. i busted thru to get to the pipe. can i just put some 6mil plastic down there, would that work?

thanks!

Click to expand...

Is this galvanized pipe?

why did you want to break off that pipe??

It is great that you were able to even thread that
pipe after you broke it off.....

whichever you do it will work ok....it dont matter

I suggest a female iron pipe to 1/2 copper sweat adapter with plenty of tefflon tape and pipe dope..

I would suggest that you only patch the hole
just good enough for visibility ...no more....

give that new fitting plenty of breatheing room
all the way down into the gravel
perhaps wrap it with an old rag or something...


or some day you might have to do it again..

pipe

ANY galvanized pipe under the floor is a potential problem, so the ideal would be to repipe the entire house, but in this case, put a coupling on the pipe and extend new galvanized to a point above the floor, wrap the pipe with protective tape, and then install the dielectric union. Do not put a union, of any kind, beneath the floor.

thanks for all the replies!

when i busted up the cement to gain access to the pipe, i broke thru a vapor barrier. can i put some 6mil plastic sheeting down there for the barrier? or do i need something special?

also, what type of cement do i want to use to fill in the hole?

thanks!

Plastic sheet (6 mil) is fine.

You fill the hole with concrete; not cement. Cement is the powdery stuff that is mixed with aggregate (sand and gravel) and water to make concrete.

Don't get mortar; that is the stuff between bricks and blocks in a wall.

For your small amount you will want a bag of "Quickcrete" or "Sackcrete" at one of the big box stores. Get the better quality kind that is marked for 2" thick appllications; not the stuff that is marked for posts and foundations. It will probably be marked 5000 psi. If you can't find those details get the better one of what is available.

An 80 pound bag will usually provide about 0.6 cubic feet, which is a hole about 12 x 24 x 3.5 inches.

Don't mix it too wet. All of the materials should be clearly wet but not at all runny. You should be able to pick it up on a shovel and it should not level out when you throw it in the hole. Too much water makes it weak, but after it sets a bit you should keep it moist for a week.

When you finish it, water and fine material will float to the top and you will be able to get a smooth finish.