Asking for a friend, because this is way outside my department. Gas company stopped by to inspect a hissing sound, and apparently found evidence of a leak in a pipe that's buried in (or under) the home's concrete slab. Gas was detected escaping to the outside of the house, near the meter. The gas (and the furnace that uses it) has been shut off. I'm afraid my friend will soon see his floors being torn up, but the guys from the gas company suggested some sort of plastic liner that could be inserted into the existing pipe from outside the house. I'm unfamiliar with such a process, and have no idea who would do such work. Can anyone educate me about this or other options?