Leak under cement floor?

[Tigercubrider]

I am trying to diagnose a fault by remote but ....

Someone that I know has a concrete floor with laminate over it
They have a water leak that dried up but it might either be from a leak under the floor or trapped water from a washing machine disaster a year ago?

Common sense says to stop using the machine for safety's sake so that for a while, the only source must be the underfloor pipe (even though the washing machine is presumed fixed)

Is it possible to try to. Find each end of the pipe and use air to pressure test?
I'm talking a few psi . I have used this to test fuel tanks and look for loss of pressure?

How does one decide that a water leak is from a buried pipe?
I don't know if copper or plastic was used or if copper, it was protected

Ta

 

[Newboy]

Do they have water trapped between the laminate and the screed?

 

[Newboy]

If there is water (rather than damp) between the laminate and the screed then first step is to eliminate above surface leaks - appliances, tap tails, waste pipework etc.

Once above surface leaks have been eliminated then start on buried services.

Water main - if a meter is fitted then close internal stopcock and check for meter movement

tank fed h&c supplies - with all outlets closed, check for flow from the (roofspace) cistern

Pressurised heating system - check for pressure drop

Open vented heating system - check for flow from the header tank

Pressure testing the pipework may be possible depending on access to the pipework.

Most above surface leaks will show as water, most embedded service leaks show as damp patches on the screed

 

[Tigercubrider]

They did but it dried out

Thanks

 

[Newboy]

So they have water stains but it's now dry?

 

[Tigercubrider]

From the message that I got , they had actual water, now dried out, under the laminate

 

[Newboy]

How long ago did the machine leak and how long ago since the laminate/screed dried out

 

[Tigercubrider]

I believe so. But they saw the water so it's not like the stain is from ages ago.

Afaik the water was noticed and the laminate was torn up to reveal the water, now dry.
Common sense says to stop use of one possible source, -washing machine, -presumably the fault with that is fixed, and run the sytem to see if more water appears.

But the location of the leak is hard to trace hence the question about pressure testing and looking for a drop that might indicate a leak

 

[Newboy]

Eliminate the possible sources one by one.

 

[Tigercubrider]

Cheers

 

[Robert Hill]

My friend also detected the leakage under slabs. On someones recommendation he contacted the professional plumbing contractors Morris County NJ to find an appropriate solution to this problem. They opened up the slab at the spot of the leak and repair leaking pipe and replaced the entire line that was leaking. They applied in-place pipe coating through the inside of plumbing.