Burst pipe in concrete floor

[Filo]

Right here goes, I`m in the proccess of having my living room floor boards ripped up and replaced with a concrete floor, the kitchen and bathroom floors are already concrete. When the builder had ripped the living room floor out he noticed that the concrete at the door between the living room and kitchen was damp below the surface, on closer inspection the damp seemed to be below the concrete but above the visqueen, he suggested there is possibly a water pipe in the concrete that has a very slight leak as there was no dripping water, just damp. Is there a way of finding out if there is a definate leak? The suspect pipework under the concrete is all after the stop tap, would it be feasable to re route the pipe work above floor level around skirting boards and then boxed in as i don`t fancy digging kitchen floor up as the units have only been in a year, thus making the under concrete pipes redundant. I`m probably looking at about 2, 30ft pipe runs, hot and cold, would that be expensive?

 

[ChrisR]

Testing pipework is routine plumbing work. Basically it's sealed and pressurised. If the pressure drops there's a leak.
Buried pipes have to be protected from anything like concrete which can corrode them, they need room to move with expansion, and tap water pipes , if not all, have to be accessible by means of someting like a cover on a duct.